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APR1400-E-E-NR-14001-NP, Rev.3, Onsite AC Power System Analysis
	ML18067A856
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Site:	05200046
Issue date:	03/08/2018
From:	; Korea Hydro & Nuclear Power Co, Ltd
To:	; Office of New Reactors
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ML18067A851	List: ML18067A852; ML18067A854; ML18067A856;
References
	KAW-18-0033, MKD/NW-18-0033L APR1400-E-E-NR-14001-NP, Rev.3
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Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP Non-Proprietary Onsite AC Power System Analysis Revision 3 Non-Proprietary January 2018 Copyright 2018 Korea Electric Power Corporation &

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP ii Non-Proprietary REVISION HISTORY Revision Date Page(s)

Description 0

December 2014 All First Issue 1

January 2016 10, 13~19, 21, 22, 24~36 Auxiliary loads are updated and acceptance criteria for bus voltage variation are revised.

2 March 2017 10, 13, 25, 27 Technical report supplement of response to RAI 413-8529, Question 08.03.01-22 is reflected.

32 LC02N, 03N transformer taps are changed. (Regulatory Audit) 15, 19~24 LC and MCC loadings are corrected as actual power consumption. (Regulatory Audit) 27, 29, 30, 32, 34 The latest load information is considered. (Regulatory Audit) 15, 16, 36 Bus transfer sequence and initiation scenarios are revised.

(Regulatory Audit) 25, 26, 29, 31, 33 Typographical errors are corrected. (Regulatory Audit) 8, 9 The double incoming circuit breakers in response to RAI 16-7915, Question 08.01-1 are reflected.

11~13 Figures are simplified for better understanding.

3 January 2018 8, 9 Several feeders from MCCs to regulating transformers (or battery charger) and a connection between LCs are corrected.

15, 19~24, 27, 29, 30, 32~35 Loading values, analysis results, and etc. are updated according to the up-to-date loads information.

31, 37 Description of analysis result is modified to meet the acceptance criteria for voltage limit of the equipment terminal.

30, 32, 33 Motor starting cases are diversified for more conservative analysis result values.

36 Bus transfer result (1-822-E-SW02M) is corrected.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 Non-Proprietary This document was prepared for the design certification application to the U.S. Nuclear Regulatory Commission and contains technological information that constitutes intellectual property of Korea Hydro & Nuclear Power Co., Ltd..

Copying, using, or distributing the information in this document in whole or in part is permitted only to the U.S.

Nuclear Regulatory Commission and its contractors for the purpose of reviewing design certification application materials. Other uses are strictly prohibited without the written permission of Korea Electric Power Corporation and Korea Hydro & Nuclear Power Co., Ltd.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP iv Non-Proprietary ABSTRACT This technical report addresses the adequacy of onsite ac power system in the Advanced Power Reactor 1400 (APR1400) by evaluating whether the electrical equipment operates properly in various plant operating modes and power source conditions. Steady-state load flow, short-circuit current, motor starting, harmonic, and bus transfer analysis are included in this report.

The plant power source conditions are categorized as main generator connected to normal preferred power supply system, unit auxiliary transformers connected to preferred power supply system through the main transformer when the generator circuit breaker is open, and standby auxiliary transformers connected to the alternate power supply system and alternate alternating current gas turbine generator.

Operating modes are normal, startup, unit trip coincident with a loss-of-coolant accident, hot standby, and station blackout condition. In Section 5, assumptions and input data are provided for analyzing onsite ac power system and the acceptance criteria to verify that the electrical equipment operates as designed are described in Section 6. All of the results of the onsite ac power system analysis meet the acceptance criteria.

This document supports Chapter 8 of the APR1400 Design Control Document, Tier 2.1)

1) APR1400-K-X-FS-14002, APR1400 Design Control Document, Tier 2, Rev. 1, KEPCO and KHNP, [March 2017].

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP v Non-Proprietary TABLE OF CONTENTS TABLE OF CONTENTS............................................................................................. v LIST OF TABLES................................................................................................... vii LIST OF FIGURES.................................................................................................viii ACRONYMS AND ABBREVIATIONS....................................................................... ix 1

INTRODUCTION.......................................................................................... 1 2

SCOPE......................................................................................................... 2 3

APPLICABLE CODES, STANDARDS, AND REGULATORY GUIDES.............. 3 3.1 U.S. Regulations....................................................................................................................3 3.2 U.S. Nuclear Regulatory Commission Guidance..................................................................3 3.3 U.S. Industry Guidance.........................................................................................................3 4

POWER SYSTEM DESCRIPTION.................................................................. 5 4.1 Offsite Power System............................................................................................................5 4.2 Onsite Power System............................................................................................................5 4.2.1 Non-Class 1E Onsite AC Power System...............................................................................6 4.2.2 Class 1E Onsite AC Power System.......................................................................................7 4.3 Source Condition and Operating Mode.............................................................................. 10 5

ASSUMPTIONS AND INPUT DATA............................................................ 14 5.1 Assumptions....................................................................................................................... 14 5.1.1 Switchyard System............................................................................................................. 14 5.1.2 Grid System Voltage Variation Range................................................................................ 14 5.1.3 Grid Short-Circuit Capability............................................................................................... 14 5.1.4 Generator Characteristic Data............................................................................................ 14 5.1.5 Power Transformer Data.................................................................................................... 15 5.1.6 Load Data........................................................................................................................... 15 5.1.7 Harmonic Equipment Data................................................................................................. 15 5.1.8 Bus Transfer Equipment Data............................................................................................ 15 5.1.9 Cable Data.......................................................................................................................... 16 5.2 Input Data........................................................................................................................... 16 5.2.1 Grid System Data............................................................................................................... 16 5.2.2 Generator........................................................................................................................... 16 5.2.3 Ratings of Power Transformer............................................................................................ 17 5.2.4 Ratings of Load Center Transformer.................................................................................. 17 5.2.5 Switchgear Rating.............................................................................................................. 17

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP vi Non-Proprietary 5.2.6 Bus Ratings........................................................................................................................ 18 5.2.7 Loads Connected to Bus.................................................................................................... 19 6

ANALYSIS.................................................................................................. 25 6.1 Steady-State Load Flow Analysis....................................................................................... 25 6.1.1 Acceptance Criteria............................................................................................................ 25 6.1.2 Analysis Result................................................................................................................... 26 6.2 Short-Circuit Current Analysis............................................................................................ 28 6.2.1 Acceptance Criteria............................................................................................................ 28 6.2.2 Analysis Result................................................................................................................... 29 6.3 Motor Starting Analysis....................................................................................................... 30 6.3.1 Acceptance Criteria............................................................................................................ 30 6.3.2 Analysis Result................................................................................................................... 31 6.4 Harmonic Analysis.............................................................................................................. 33 6.4.1 Acceptance Criteria............................................................................................................ 33 6.4.2 Analysis Results................................................................................................................. 34 6.5 Bus Transfer Analysis......................................................................................................... 35 6.5.1 Acceptance Criteria............................................................................................................ 35 6.5.2 Analysis Results................................................................................................................. 35 7

CONCLUSIONS.......................................................................................... 37 8

REFERENCES............................................................................................ 38

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP vii Non-Proprietary LIST OF TABLES Table 5-1 Generator Characteristic Data................................................................................. 14 Table 5-2 Grid System Data.................................................................................................... 16 Table 5-3 Generator Input Data............................................................................................... 16 Table 5-4 Ratings of Power Transformer................................................................................. 17 Table 5-5 Ratings of Load Center Transformer....................................................................... 17 Table 5-6 Bus Ratings............................................................................................................. 18 Table 5-7 13.8 kV Bus 1-821-E-SW01M Loads....................................................................... 19 Table 5-8 13.8 kV Bus 1-821-E-SW02M Loads....................................................................... 19 Table 5-9 4.16 kV PNS Bus 1-822-E-SW01M Loads.............................................................. 20 Table 5-10 4.16 kV Bus 1-822-E-SW02M Loads....................................................................... 20 Table 5-11 4.16 kV Bus 1-823-E-SW01A Loads....................................................................... 21 Table 5-12 4.16 kV Bus 1-823-E-SW01C Loads....................................................................... 21 Table 5-13 13.8 kV Bus 1-821-E-SW01N Loads....................................................................... 22 Table 5-14 13.8 kV Bus 1-821-E-SW02N Loads....................................................................... 22 Table 5-15 4.16 kV PNS Bus 1-822-E-SW01N Loads............................................................... 23 Table 5-16 4.16 kV Bus 1-822-E-SW02N Loads....................................................................... 23 Table 5-17 4.16 kV AAC Bus 1-822-E-SW03N Loads............................................................... 23 Table 5-18 4.16 kV Bus 1-823-E-SW01B Loads....................................................................... 24 Table 5-19 4.16 kV Bus 1-823-E-SW01D Loads....................................................................... 24 Table 6-1 Acceptance Criteria for Bus Voltage Variation at the Steady-state......................... 25 Table 6-2 Minimum operating Voltage Summary of Non-Class 1E Buses (Unit: %)............... 27 Table 6-3 Minimum operating Voltage Summary of Class 1E Buses (Unit: %)....................... 27 Table 6-4 Maximum operating Voltage Summary of Non-Class 1E Buses (Unit: %).............. 28 Table 6-5 Maximum operating Voltage Summary of Class 1E Buses (Unit: %)...................... 28 Table 6-6 Acceptance Criteria for Bus Short-circuit Current................................................... 29 Table 6-7 Short-Circuit Current Summary of Non-Class 1E Buses at All Operating Conditions (Unit: kA).................................................................................................................. 29 Table 6-8 Short-Circuit Current Summary of Class 1E Buses at All Operating Conditions (Unit: kA).................................................................................................................. 30

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP viii Non-Proprietary Table 6-9 Acceptance Criteria for Bus Voltage Variation during the Starting of Large Motors 31 Table 6-10 Motor Starting Summary of Non-Class 1E Buses (Unit: %).................................... 32 Table 6-11 Motor Starting Summary of Class 1E Buses (Unit: %)............................................ 32 Table 6-12 Acceptance Criteria for Harmonic Analysis............................................................. 33 Table 6-13 Maximum Total Harmonic Distortion in Non-Class 1E Buses (Unit: %)................... 34 Table 6-14 Maximum Total Harmonic Distortion in Class 1E Buses (Unit: %).......................... 34 Table 6-15 Transient Analysis Summary of Bus Transfer.......................................................... 36 LIST OF FIGURES Figure 4-1 Onsite Power System...............................................................................................8 Figure 4-2 Source 1 - MG connected to 765 kV Offsite Power System..................................... 11 Figure 4-3 Source 2 - UATs connected to 765 kV Offsite Power System through the MT when the GCB opens (Back-feeding)................................................................................. 11 Figure 4-4 Source 3 - SATs connected to 154 kV Offsite Power System................................. 12 Figure 4-5 Source 4 - AAC GTG............................................................................................... 12 Figure 4-6 Source 5 - EDGs...................................................................................................... 13

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP ix Non-Proprietary ACRONYMS AND ABBREVIATIONS AAC alternate alternating current ASME American Society of Mechanical Engineers bhp brake horsepower BTP Branch Technical Position CCW component cooling water CFR Code of Federal Regulations DCD design control document EDG emergency diesel generator ESF engineered safety features ETAP electrical transient analyzer program GCB generator circuit breaker GDC general design criteria GTG gas turbine generator IEEE Institute of Electrical and Electronics Engineers IPB isolated phase bus KEPCO Korea Electric Power Corporation KHNP Korea Hydro & Nuclear Power Co., Ltd LC load center LOCA loss-of-coolant accident LOOP loss of offsite power LV low voltage MCC motor control center MG main generator MT main transformer MV medium voltage NEMA National Electrical Manufacturers Association NFPA National Fire Protection Association NQA Nuclear Quality Assurance NSSS nuclear steam supply system PNS permanent non-safety PPS preferred power supply pu per unit RCP reactor coolant pump RG Regulatory Guide

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP x Non-Proprietary RPS reactor protection system SAT standby auxiliary transformer SBO station blackout SKN 3&4 Shin-Kori Nuclear Power Plant Units 3 and 4 TGB turbine generator building THD total harmonic distortion TS trade secret UAT unit auxiliary transformer

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 1 Non-Proprietary

1.

INTRODUCTION The purpose of this report is to provide the results of the analysis as referenced by the APR1400 Design Control Document (DCD) Tier 2, Subsection 8.3.1 (Reference 1), and to evaluate the design adequacy of the onsite ac power system in the APR1400. The analysis includes steady-state load flow, short-circuit current, motor starting, harmonics, and bus transfer. It is performed using the electrical transient analyzer program (ETAP), version 12.0.0N, which is qualified for nuclear power plants in conformance with 10 CFR 50, Appendix B (Reference 2), 10 CFR 50.21 (Reference 3), and American Society of Mechanical Engineers (ASME) NQA-1 (Reference 4).

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 2 Non-Proprietary

2.

SCOPE This report includes the following electrical power system calculations and distribution system studies:

Steady-state load flow analysis Short-circuit analysis Motor starting analysis Harmonic analysis Bus transfer analysis

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 3 Non-Proprietary

3.

APPLICABLE CODES, STANDARDS, AND REGULATORY GUIDES The electric power system is designed to meet the following requirements of General Design Criteria (GDCs), Regulatory Guides (RGs), Branch Technical Positions (BTPs), and industry standards.

3.1.

U.S. Regulations General Design Criterion 17, Electric Power Systems, 10 CFR 50, Appendix A.

General Design Criterion 18, Inspection and Testing of Electric Power Systems, 10 CFR 50, Appendix A.

10 CFR 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants.

10 CFR 21, Reporting of Defects and Noncompliance.

3.2.

U.S. Nuclear Regulatory Commission Guidance NRC RG 1.75, Criteria for Independence of Electrical Safety Systems, Rev. 3, U.S. Nuclear Regulatory Commission, February 2005.

NRC RG 1.93, Availability of Electric Power Sources, Rev. 1, U.S. Nuclear Regulatory Commission, March 2012.

NRC RG 1.155, Station Blackout, Rev. 0, U.S. Nuclear Regulatory Commission, August 1988.

BTP 8-6, Adequacy of Station Electric Distribution System Voltages, Rev. 3, U.S. Nuclear Regulatory Commission, March 2007.

3.3.

U.S. Industry Guidance IEEE Std 141-1993, IEEE Recommended Practice for Electric Power Distribution for Industrial Plants, Institute of Electrical and Electronics Engineers, 1993.

IEEE Std 384-1992, IEEE Standard Criteria for Independence of Class 1E Equipment and Circuits, Institute of Electrical and Electronics Engineers, 1992.

IEEE Std 387-1995, IEEE Standard Criteria for Diesel-Generator Units Applied as Standby Power Supplies for Nuclear Power Generating Stations, Institute of Electrical and Electronics Engineers, 1995.

IEEE Std 399-1997, IEEE Recommended Practice for Industrial and Commercial Power System Analysis, Institute of Electrical and Electronics Engineers, 1997.

IEEE Std 519-1992, IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems, Institute of Electrical and Electronics Engineers, 1992.

IEEE Std 765-2006, IEEE Standard for Preferred Power Supply (PPS) for Nuclear Power Generating Stations (NPGS), Institute of Electrical and Electronics Engineers, 2006.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 4 Non-Proprietary IEEE Std C37.010-1999, IEEE Application Guide for AC High Voltage Circuit Breakers Rated on a Symmetrical Current Basis, Institute of Electrical and Electronics Engineers, 1999.

NEMA MG-1, Motors and Generators, National Electrical Manufacturers Association, 2009.

ANSI C50.41, American National Standard for Polyphase Induction Motors for Power Generating Stations, American National Standards Institute, 2000.

NEMA WC 51, Ampacities for Cables Installed in Cable Trays, National Electrical Manufacturers Association, 2009.

NFPA 70, National Electrical Code, National Fire Protection Association, 2008.

ASME NQA-1, Quality Assurance Requirements for Nuclear Facility Applications, The American Society of Mechanical Engineers, 2008.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 5 Non-Proprietary

4.

POWER SYSTEM DESCRIPTION 4.1.

Offsite Power System The offsite power system is the preferred source of power for the reactor protection system (RPS) and engineered safety features (ESF) during normal, abnormal, and accident conditions. It includes two physically independent circuits from the transmission network. The switchyard is connected to the transmission lines to transmit the electricity produced by the APR1400 to the grid and to provide offsite power to auxiliary and service loads of the APR1400.

Electric power from the transmission network to the onsite electrical distribution system is supplied by two physically independent circuits.

The offsite power system encompasses the grid, overhead or underground transmission lines, transmission line towers, switchyard components and control systems, switchyard battery systems, the main generator (MG), generator circuit breaker (GCB), main transformer (MT), unit auxiliary transformers (UATs), standby auxiliary transformers (SATs), isolated phase buses (IPBs), and electrical components associated with them. The boundaries between the offsite power system and the onsite power system are the incoming circuit breakers of the switchgears and the circuit breakers, which are included in the onsite power system.

One separate circuit is connected to the switchyard via the MT. The MG is connected to the low-voltage (LV) winding of the MT and the high-voltage winding of the UATs through the GCB. The UATs are connected to the IPB between the GCB and the MT. Under normal operating conditions, the MG supplies power through the GCB to the MT and two UATs.

The other separate circuit is connected to the switchyard via two SATs, to provide an immediately available independent source of offsite power to the onsite power distribution system for safety and non-safety loads when power is not available through UATs.

The GCB is used as a means of providing immediate access of the onsite ac power systems to offsite circuits by isolating the MG from the MT and the UATs and allowing back-feeding of power through these circuits to the onsite ac power system. The GCB is capable of interrupting normal load current and maximum fault current during transient and various fault conditions.

Each preferred power circuit has capacity and capability to permit functioning of structures, systems, and components (SSCs) important to safety and all other auxiliary systems under normal, abnormal, and accident conditions.

4.2.

Onsite Power System The onsite power system for the APR1400, as shown in Figure 4-1, consists of the following systems and components:

Non-Class 1E 13.8 kV system Non-Class 1E and Class 1E 4.16 kV systems Non-Class 1E and Class 1E 480V systems Emergency diesel generators (EDGs)

An alternate alternating current (AAC) gas turbine generator (GTG)

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 6 Non-Proprietary The onsite power system is normally powered from the MG through the two UATs. In case power is unavailable from the UATs, the power source of UATs is automatically transferred to the SATs and all Class 1E and non-Class 1E MV switchgear buses are powered from the SATs.

During startup and shutdown, onsite ac power is supplied from the switchyard through the MT and UATs.

The Class 1E loads are divided into two redundant load groups, division I and division II, and each division has two independent subsystems. Each independent subsystem consists of trains A and C for division I and trains B and D for division II.

If both offsite power sources and the EDGs are unavailable, the Class 1E train A or train B is powered independently by the AAC GTG.

The onsite ac power system includes standby power sources, distribution systems, auxiliary supporting systems provided to supply power to safety-related equipment or equipment important to safety for all normal operating and accident conditions. The four EDGs and an AAC GTG are used as a standby power source for the onsite ac power system. The Class 1E EDGs provide backup power to the Class 1E 4.16 kV buses in the event of loss of offsite power (LOOP). The non-Class 1E AAC GTG provides backup power to the permanent non-safety (PNS) buses during a LOOP and to the dedicated Class 1E 4.16 kV bus during a station blackout (SBO).

4.2.1 Non-Class 1E Onsite AC Power System There are one UAT and one SAT, which provide power to 13.8 kV and 4.16 kV switchgears in each division. During normal plant operation, two non-Class 1E 13.8 kV switchgears, one non-Class 1E 4.16 kV switchgear, one PNS 4.16 kV switchgear, and one non-Class 1E AAC 4.16 kV switchgear are powered from UAT.

The AAC GTG is automatically started by undervoltage relay and manually connected to two PNS buses (division I and division II) during a LOOP. The loads, which are not safety-related but required during a LOOP, are connected to PNS buses manually. The AAC GTG is adequately sized to meet the load requirements during LOOP or SBO conditions.

Load center (LC) transformers are connected to 13.8 kV or 4.16 kV switchgears, and provide power to its 480V LC buses. The non-Class 1E motor control center (MCC) buses are connected to the non-Class 1E LC buses.

4.2.1.1.

13.8 kV Onsite AC Power System The 13.8 kV onsite ac power system consists of four non-Class 1E switchgears and supplies power to large motors such as the reactor coolant pump motors, condensate pump motors, feedwater booster pump motors, circulating water pump motors, startup feedwater pump motor, cooling tower fan, and associated 480V LCs.

4.2.1.2.

4.16 kV Onsite AC Power System The 4.16 kV onsite ac power system consists of two non-Class 1E switchgears, two PNS switchgears, and a non-Class 1E switchgear with non-Class 1E AAC GTG. The two non-Class 1E switchgears supply power to the turbine generator building closed cooling water pump and 480V LCs. The PNS switchgear supplies power to the central chillers, central chilled water pump, and 480V LCs, which are required to operate in a LOOP condition.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 7 Non-Proprietary 4.2.1.3.

480V Onsite AC Power System The 480V onsite ac power system is energized by the 13.8 kV and 4.16 kV switchgears through 13.8 kV /

480V and 4.16 kV / 480V transformers. The secondary of the transformer is connected to a 480V LC bus through a 480V LC incoming breaker. The 480V LCs are distributed throughout the plant area and located indoors. Motors, heaters, and 480V MCCs are assigned to the LCs. The non-Class 1E MCCs are located in the various indoor areas of the plant.

4.2.2 Class 1E Onsite AC Power System The Class 1E onsite ac power system consists of two redundant load groups (division I and division II),

which have four EDGs, 4.16 kV switchgears, 480V LCs, 480V MCCs, and miscellaneous low-voltage (LV) ac supplies.

The Class 1E 4.16 kV switchgears are connected to the offsite power sources through the UAT or the SAT in each division. Each Class 1E 4.16 kV switchgear is also powered by an EDG for a safe shutdown during a LOOP concurrent with loss-of-coolant accident (LOCA) conditions, and the Class 1E train A or train B switchgear has access to the non-Class 1E AAC GTG during an SBO condition. Each 4.16 kV bus supplies power to the motor loads and 4.16 kV / 480V LC transformers.

The Class 1E 4.16 kV switchgears are located in the auxiliary building. Each switchgear is arranged as an independent distribution system, located in a separate fire zone in a seismic Category I room.

LC transformers connected to the Class 1E 4.16 kV buses provide power to Class 1E 480V LC buses.

The Class 1E 480V MCC buses are connected to the Class 1E LC buses.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 8

Non-Proprietary MAIN GEN 24KV GEN. CIRCUIT BKR TO UNIT AUX. XFMR 1N NO NON-CLASS 1E 13.8KV SWGR 1M RC PUMP 1A,2A M

UNIT AUX. XFMR 1M H

EXCITATION XFMR EXCITATION SYSTEM Y

X 13.8KV 4.16KV CONDENSATE PUMP A FW BOOSTER A,C CW PUMP A,C,E M

NON-CLASS 1E 13.8KV SWGR 2M 13800-480V XFMR 480V LC MCC 480V LC 13800-480V XFMR MCC BATT.

CHARGER (STAND-BY)

TO 250V DC CONT.

CENTER REG. XFMR 480-120V, 1

NO TGBCCW PUMP 1 M

BATT.

CHARGER (STAND-BY)

BATT.

CHARGER TO 125V DC CONT.

CENTER M

480V LC A

M REG. XFMR 480-120V, 1

120V AC DISTR. PNL INVERTER MCC NON-CLASS 1E 4.16KV SWGR 2M NO 125V DC CONT.

CENTER NO CLASS 1E 4.16KV SWGR 1A SC PUMP 1 SI PUMP 1 ESW PUMP 1A AF PUMP A CCW PUMP 1A ESS CHILLER 1A CHARGING PUMP 1 COOLING TOWER FAN 1A M

480V LC 1A 4160-480V XFMR MCC 1A BATT.

CHARGER 1A REG. XFMR 1A 480-120V, 1 480V LC 2(SWING BUS) 125V DC CONT.

CENTER 1A 480V LC 1C 4160-480V XFMR MCC 1C REG. XFMR 1C 480-120V, 1 CLASS 1E EMERGENCY DIESEL GEN. 1C NO NO NO CS PUMP 1 SI PUMP 3 ESW PUMP 2A CCW PUMP 2A ESS CHILLER 2A COOLING TOWER FAN 2A M

IPB 13.8KV 4.16KV CLASS 1E 4.16KV SWGR 1C Y

X H

480V LC 4160-480V XFMR MCC CENTRAL CHILLER 1,2 CENTRAL CHILLED WATER PUMP 1 M

PERMANENT NON-SAFETY 4.16KV SWGR 1M 4160-480V XFMR PRESS HTRS BACK-UP GROUP B-1 MCC CLASS 1E EMERGENCY DIESEL GEN. 1A NO NO M

BATT.

CHARGER 1C M

BATT.

CHARGER 2A (STAND-BY)

BATT.

CHARGER 2C (STAND-BY) 4160-480V XFMR 480V LC 4160-480V XFMR MCC NO NO NO NO 24KV NON-CLASS 1E TO STAND-BY AUX XFMR 2N STAND-BY AUX. XFMR 2M PLANT MAIN XFMR PLANT CLASS 1E TRAIN A TRAIN C 125V DC CONT.

CENTER 1C NO TO 480V LC 1B NON-CLASS 1E SWITCHYARD SWITCHYARD NO TO AAC SWGR TO AAC SWGR A

M 120V AC DISTR. PNL A

M 120V AC DISTR. PNL INVERTER 1A INVERTER 1C INVERTER 125V DC BATTERY 125V DC BATTERY 1A 125V DC BATTERY 1C CONNECTION BOX FOR MOBILE GTG 1M 1

2 3

4 A

B A

B 5

1A AUX. CHARGING PUMP3 M

DUMMY BKR.

CONNECTION BOX FOR 480V MOBILE GTG NO NO COOLING TOWER FAN GROUP ADMIN BLDG Figure 4-1. Onsite Power System (1 of 2)

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 9

Non-Proprietary 1

TO MAIN GENERATOR NO NON-CLASS 1E 13.8KV SWGR 1N RC PUMP 1B,2B M

UNIT AUX. XFMR 1N H

Y X

13.8KV 4.16KV CONDENSATE PUMP B,C FW BOOSTER B CW PUMP B,D,F START-UP FW PUMP M

NON-CLASS 1E 13.8KV SWGR 2N 13800-480V XFMR 480V LC MCC 480V LC 13800-480V XFMR MCC BATT.

CHARGER REG. XFMR 480-120V, 1 TGBCCW PUMP 2 M

480V LC 4160-480V XFMR MCC BATT.

CHARGER M

480V LC REG. XFMR 480-120V, 1 MCC NON-CLASS 1E 4.16KV SWGR 2N NO 125V DC CONTROL CENTER NO SC PUMP 2 SI PUMP 2 ESW PUMP 1B AF PUMP B CCW PUMP 1B ESS CHILLER 1B CHARGING PUMP 2 COOLING TOWER FAN 1B M

480V LC 1B 4160-480V XFMR BATT.

CHARGER 1B REG. XFMR 1B 480-120V, 1 125V DC CONT.

CENTER 1B 480V LC 1D 4160-480V XFMR MCC 1D BATT.

CHARGER 1D REG. XFMR 1D 480-120V, 1 125V DC CONT.

CENTER 1D CLASS 1E EMERGENCY DIESEL GEN. 1D NO NO NO CS PUMP 2 SI PUMP 4 ESW PUMP 2B CCW PUMP 2B ESS CHILLER 2B COOLING TOWER FAN 2B M

IPB STAND-BY AUX. XFMR 2N 13.8KV 4.16KV CLASS 1E 4.16KV SWGR 1D Y

X H

SWITCHYARD 480V LC 4160-480V XFMR MCC CENTRAL CHILLER 3,4 CENTRAL CHILLED WATER PUMP 2 M

PERMANENT NON-SAFETY 4.16KV SWGR 1N TO 480V LC 2 5

M TO STAND-BY BATT. CHARGER 250V DC CONT.

CENTER REG. XFMR 480-120V, 1 UPS BATT.

CHARGER F

125V DC CONT.

CENTER 3

NON-CLASS 1E 4.16KV AAC SWGR 3N 480V LC 4160-480V XFMR NO 1

N TO 4.16KV SWGR 1M TO 4.16KV SWGR 1N MCC 125V DC BATTERY 125V DC CONT.

CENTER AAC GENERATOR NO NO CLASS 1E EMERGENCY DIESEL GEN. 1B NO M

M BATT.

CHARGER 2B (STAND-BY)

BATT.

CHARGER 2D (STAND-BY) 4160-480V XFMR MCC 1B BATT.

CHARGER NO NO TO 4.16KV SWGR 1B TO 4.16KV SWGR 1A 1

B 4160-480V XFMR PRESS HTRS BACK-UP GROUP B-2 MCC CLASS 1E 4.16KV SWGR 1B TRAIN B TRAIN D CLASS 1E NON-CLASS 1E NON-CLASS 1E NON-CLASS 1E 2

NO NO NO A

M 120V AC DISTR. PNL INVERTER A

M 120V AC DISTR. PNL INVERTER 1B A

M 120V AC DISTR. PNL INVERTER 1D 120V AC DISTR. PNL U P S REG. XFMR 480-120V, 1 TG UPS 120V AC DISTR. PNL U P S 125V DC BATTERY 1D 125V DC BATTERY 1B 125V DC BATTERY 125V DC BATTERY 250V DC BATTERY MCC REG. XFMR 480-120V, 1 AAC UPS 120V AC DISTR. PNL U P S TO STAND-BY BATT. CHARGER CONNECTION BOX FOR MOBILE GTG 4

1N 1B K

E C

D C

D E

F 3

1 2

1B 1N 1A 1M NO CONNECTION BOX FOR 480V MOBILE GTG NO COOLING TOWER FAN GROUP TO CPB MCC TO AAC SWGR TO AAC SWGR F

FK H

H MCC NO Figure 4-1. Onsite Power System (2 of 2)

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 10 Non-Proprietary 4.3.

Source Condition and Operating Mode This section presents the source conditions based on operating modes of the APR1400 nuclear steam supply system (NSSS) response to postulated disturbances in process variables and to postulated malfunctions or failures of equipment. Such incidents (or events) are postulated and their consequences are analyzed despite the many precautions that are taken in the design, construction, quality assurance, and plant operation to prevent their occurrence. The effects of these incidents are examined to determine their consequences and to evaluate the capability built into the plant to control or accommodate such failures and situations.

To evaluate the adequacy of auxiliary power system design and load assignments, the various plant operating modes and the source conditions are considered. As part of the evaluation, the loading are categorized into the following eight levels according to plant conditions:

Loading Categories Category 1:

Normal operation from UAT Category 2:

Startup from UAT Category 3:

Unit trip coincident with LOCA from UAT Category 4:

Hot standby from UAT Category 5:

Unit trip coincident with LOCA from SAT Category 6:

Hot standby from SAT Category 7:

SBO from AAC GTG Category 8:

LOOP coincident with LOCA from EDG The five sources of power feeding the auxiliary system loads are shown in Figures 4-2 through 4-6.

These sources are as follows, and the valid load conditions for the respective sources are denoted in parentheses.

Source 1:

MG connected to 765 kV offsite power system. This source is valid for loading category 1 (Normal).

Source 2:

UATs connected to 765 kV offsite power system through the MT when the GCB opens (back-feeding). This source is valid for loading categories 2, 3, and 4 (startup, unit trip with LOCA, and hot standby).

Source 3:

SATs connected to 154 kV offsite power system. This source is valid for loading categories 5 and 6 (unit trip with LOCA, hot standby).

Source 4:

AAC GTG. This source is valid for loading category 7 (SBO).

Source 5:

EDGs. This source is valid for loading category 8 (LOOP with LOCA).

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 11 Non-Proprietary M

TO 765 kV SWITCHYARD MAIN XFMR H

X Y

UAT 01M 13.8 kV SWGR DIV.I M

4.16 kV SWGR DIV.I 4.16 kV/

480V 13.8 kV/

480V M

X Y

UAT 01N 13.8 kV SWGR DIV.II M

4.16 kV SWGR DIV.II 4.16 kV/

480V 13.8 kV/

480V H

M MG TO 765 kV SWITCHYARD MAIN XFMR H

X Y

UAT 01M 13.8 kV SWGR DIV.I M

4.16 kV SWGR DIV.I 4.16 kV/

480V 13.8 kV/

480V M

X Y

UAT 01N 13.8 kV SWGR DIV.II M

4.16 kV SWGR DIV.II 4.16 kV/

480V 13.8 kV/

480V H

GCB Figure 4-2. Source 1 - MG connected to 765 kV Offsite Power System Figure 4-3. Source 2 - UATs connected to 765 kV Offsite Power System through the MT when the GCB opens (Back-feeding)

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 12 Non-Proprietary Figure 4-4. Source 3 - SATs connected to 154 kV Offsite Power System 4.16 kV AAC SWGR AAC GTG 4.16 kV SWGR TRAIN A (or B)

M 4.16 kV/

480V Figure 4-5. Source 4 - AAC GTG TO 154 kV SWITCHYARD H

X Y

SAT 02M 13.8 kV SWGR DIV.I 4.16 kV SWGR DIV.I X

Y 13.8 kV SWGR DIV.II 4.16 kV SWGR DIV.II H

SAT 02N M

M 4.16 kV/

480V 13.8 kV/

480V M

M 4.16 kV/

480V 13.8 kV/

480V

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 13 Non-Proprietary EDG 1A (or 1B) 4.16 KV SWGR TRAIN A (or B)

M 4.16 kV/

480V EDG 1C (or 1D)

M 4.16 kV/

480V 4.16 KV SWGR TRAIN C (or D)

Figure 4-6. Source 5 - EDGs

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 14 Non-Proprietary

5.

ASSUMPTIONS AND INPUT DATA 5.1.

Assumptions The plant switchyard design is site-specific and some characteristic data of major equipment are obtained at the detailed design stage of the project. Therefore, the following data are assumed based on the reference plant, Shin-Kori Nuclear Power Plant Units 3 and 4 (SKN 3&4) to analyze the onsite ac power system.

5.1.1 Switchyard System In the switchyard system, two switchyards that have different rated voltage level are assumed. One, the 765 kV switchyard, is connected to the MT and the other, the 154 kV switchyard, is connected to SATs.

5.1.2 Grid System Voltage Variation Range The grid voltage variations between the maximum and the minimum are as follows:

Maximum: 1.05 per unit (pu) of rated voltage Minimum: 0.95 pu of rated voltage 5.1.3 Grid Short-Circuit Capability The maximum short-circuit capability and X/R ratio of the 765 kV grid and 154 kV grid are as follows:

Maximum short-circuit capability: 63 kA, X/R: 40 (765 kV grid)

Maximum short-circuit capability: 50 kA, X/R: 10 (154 kV grid) 5.1.4 Generator Characteristic Data The following data are derived from the manufacturers characteristic data for the reference plant of the APR1400.

Table 5-1. Generator Characteristic Data Items MG EDG AAC GTG Xd 0.245 pu 0.16 pu 1) 0.16 pu 1)

X/R ratio 120.7 50 50 Notes

1) These data are interpolated from the manufacturers characteristics data from the reference plant of the APR1400.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 15 Non-Proprietary 5.1.5 Power Transformer Data 5.1.5.1 Main Transformer The MT consists of three single phase transformers.

No load tap changer (NLTC) is applied at the primary winding of the main transformer.

5.1.5.2 Unit Auxiliary Transformers and Standby Auxiliary Transformers The UATs and SATs are designed as three phase transformer.

On load tap changer (OLTC) is applied at the primary winding of UATs and SATs.

The OLTC tap range and number of taps are determined based on the grid voltage variation, impedance and auxiliary loads of the onsite power system. The upper tap limit of the OLTC is plus 5 percent and the lower tap limit of the OLTC is minus 15 percent from the center tap for each UAT and SAT.

The dead band (upper and lower band) of the OLTC is assumed to be plus/minus 2 percent of rated voltage of the regulated bus for reliable operation of the plant so that the regulated voltage of the switchgear is maintained between 98 and 102 percent of switchgear nominal voltage.

5.1.6 Load Data Large loads for 13.8 kV switchgears, 4.16 kV switchgears, and 480V LCs are addressed in DCD Tier 2, Chapter 8, Tables 8.3.1-1 through 8.3.1-5, with consideration of the APR1400 site envelope design.

Assumptions of the locked rotor currents (LRCs), X/R ratios, power factors, efficiencies, and subtransient reactances of medium voltage motors are derived from the experience data of the reference plant of the APR1400. The static and miscellaneous loads, and motor-operated valves (MOVs) fed from the 480V LCs and MCCs that are not within the scope of the APR1400 design certification are derived from the load list of the reference plant of the APR1400.

5.1.7 Harmonic Equipment Data Harmonics are generated by nonlinear equipment such as battery chargers, inverters, and switch mode power supplies. Generated harmonics have an impact on the motors and generator, transformers, power cables, capacitors, electronic equipment, metering, and switching and relays. In this report, harmonic models for battery chargers are conservatively applied by selecting a six-pulse rectifier model.

5.1.8 Bus Transfer Equipment Data The assumptions and load data in Sections 5.1 and 5.2 are used for bus transfer analysis.

The motor modeling, relay characteristic, and equipment operation data, which affect bus transfer analysis, are assumed based on the reference plant of the APR1400.

Major factors and assumptions for bus transfer analysis are as below; Voltage phase difference between two off-site sources : zero

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 16 Non-Proprietary Bus transfer initiation scenarios

- 3 phase fault at 13.8 kV winding of UAT (Div. I)

- 3 phase fault at 4.16 kV winding of UAT (Div. I)

- Line-to-ground fault at IPB Fault clearing time : 0.07 sec Bus dead time : 0.053 sec Dynamic modeling motor loads : All MV motor loads 5.1.9 Cable Data Cable sizes and assumed lengths based on the reference plant of the APR1400, are used for feeders to MV switchgears and LV LCs. This is done to facilitate model updates when actual cable sizes and lengths become available.

5.2.

Input Data 5.2.1 Grid System Data Table 5-2. Grid System Data Items 765 kV Switchyard 154 kV Switchyard Circuit Breaker Rating 63 kA 50 kA X/R ratio 40 10 Voltage Range 765 kV +/- 5 %

154 kV +/- 5 %

5.2.2 Generator Table 5-3. Generator Input Data Items MG EDG AAC GTG Capacity 1,690,000 kVA 9,100/7,500 kW (for trains A&B/C&D) 9,700 kW Power Factor 90 %

80 %

Voltage 24 kV 4.16 kV 4.16 kV Xd 0.245 pu 0.16 pu 0.16 pu Var Limit (MVAR)

Maximum 736.7 6.825 7.275 Minimum

-527.6

-2.131

-3.786 X/R Ratio 120.7 50 50

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 17 Non-Proprietary 5.2.3 Ratings of Power Transformer Table 5-4. Ratings of Power Transformer Items MT UAT SAT Voltage 800-24 kV 24-14.49/4.37 kV 154-13.8/4.16 kV MVA 1670 MVA H = 71.0/94.7 MVA @ 55 ºC X = 48.0/64.0 MVA @ 55 ºC Y = 23.0/30.7 MVA @ 55 ºC H = 67.0/89.4 MVA @ 55 ºC X = 44.0/58.7 MVA @ 55 ºC Y = 23.0/30.7 MVA @ 55 ºC

%Z Z=19 %

(Tolerance:

+/- 7.5 %)

ZHX = 10.5 % @ 71.0 MVA ZHY = 36.0 % @ 71.0 MVA ZXY = 46.5 % @ 71.0 MVA (Tolerance: +/- 20 %)

ZHX = 11.1 % @ 67.0 MVA ZHY = 38.0 % @ 67.0 MVA ZXY = 49.1 % @ 67.0 MVA (Tolerance: +/- 20 %)

X/R Ratio 79 25 25 5.2.4 Ratings of Load Center Transformer Table 5-5. Ratings of Load Center Transformer kVA (AA/FA) 350 500/667 750/1000 1000/1333 1500/2000 Voltage (kV) 4.16-0.48 13.8-0.48 4.16-0.48 4.16-0.48 13.8-0.48 4.16-0.48 13.8-0.48

%Z1)

(Tolerance) 2)

Z= 4 %

(+/-7.5 %)

Z= 4 %

(+/-7.5 %)

Z= 5.75 %

(+/-7.5 %)

Z= 5.75 %

(+/-7.5 %)

Z= 5.75 %

(+/-7.5 %)

Cooling Class AA3)

AA/FA4)

AA/FA AA/FA AA/FA Notes

1) Percent impedance values are experience data from the reference plant of the APR1400.

2) Tolerances of percent impedances are applied in accordance with IEEE Std C57.12.01.

3) AA (ambient air; One of the transformer cooling class, which stands for ventilated self-cooled)

4) FA (forced air; One of the transformer cooling class, which stands for forced-air-cooled) 5.2.5 Switchgear Rating 5.2.5.1 13.8 kV Switchgear Breaker Rated short-circuit currents, rms: 50 kA Closing and latching capability, peak: 130 kA Rated voltage range factor: 1.0 Rated maximum voltage: 15 kV Rated interrupting time: 5 cycles

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 18 Non-Proprietary 5.2.5.2 4.16 kV Switchgear Breaker Rated short-circuit current, rms: 50 kA Closing and latching capability, peak: 130 kA Rated voltage range factor: 1.0 Rated maximum voltage: 4.76 kV Rated interrupting time: 5 cycles 5.2.5.3 480V LC Breaker Rated short-circuit currents, rms: 30 kA or 50 kA Rated maximum voltage: 508V Rated interrupting time: within 3 cycles 5.2.5.4 480V MCC Breaker Rated short-circuit currents, rms: 30 kA or 50 kA1)

Rated maximum voltage: 508V Rated interrupting time: within 1 cycle Notes

1) For the commercial availability and maintenance, the short-circuit rating of MCC breaker is selected as 50 kA.

5.2.6 Bus Ratings Table 5-6. Bus Ratings Items Nominal Voltage (kV)

Continuous Current Rating (A)

Short-Time Current Rating (kA, rms)

Isolated Phase Bus (Main) 24.0 43,000 230 13.8 kV Switchgear Bus (Horizontal) 13.8 2,000 50 4.16 kV Switchgear Bus (Horizontal) 4.16 1,200 50 2,000 50 3,000 50 480V L/C Bus with Transformer (Horizontal) 350 kVA @ AA rating 0.48 1,600 30 667 kVA @ FA rating 1,600 30 1,000 kVA @ FA rating 1,600 30 1,333 kVA @ FA rating 2,000 30

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 19 Non-Proprietary 2,000 kVA @ FA rating 3,000 50 480V MCC Bus (Horizontal) 0.48 600 30/42 5.2.7 Loads Connected to Bus The load capacity in brake horsepower (bhp) is used under all operation modes.

5.2.7.1 13.8 kV Bus loads (Division I)

Table 5-7. 13.8 kV Bus 1-821-E-SW01M Loads Load Name Bus Voltage Unit Rated Reactor Coolant Pump 1A 13.8 kV hp 13,500 Reactor Coolant Pump 2A 13.8 kV hp 13,500 LC 01M Loads 480V kVA LC 02M Loads 480V kVA LC 03M Loads 480V kVA Table 5-8. 13.8 kV Bus 1-821-E-SW02M Loads Load Name Bus Voltage Unit Rated Condensate Pump A 13.8 kV hp 4,600 Feedwater Booster Pump A 13.8 kV hp 5,000 Feedwater Booster Pump C 13.8 kV hp 5,000 Circulating Water Pump A 13.8 kV hp 4,357 Circulating Water Pump C 13.8 kV hp 4,357 Circulating Water Pump E 13.8 kV hp 4,357 LC 04M Loads 480V kVA LC 06M Loads 480V kVA LC 16M Loads 480V kVA Cooling Tower Fan Group Loads Load Group 1 480V kVA Load Group 2 480V kVA Load Group 3 480V kVA Load Group 4 480V kVA Fire Pump & Water/Wastewater Treatment Facility Area Loads (Future)

TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 20 Non-Proprietary Load Name Bus Voltage Unit Rated Load Group 1 480V kVA Load Group 2 480V kVA 5.2.7.2. 4.16 kV Bus Loads (Division I, Trains A and C)

Table 5-9. 4.16 kV PNS Bus 1-822-E-SW01M Loads Load Name Bus Voltage Unit Rated Central Chiller 1 4.16 kV hp 1,100 Central Chiller 2 4.16 kV hp 1,100 Central Chilled Water Pump 1 4.16 kV hp 500 LC 10M Loads 480V kVA LC 12M Loads 480V kVA Table 5-10. 4.16 kV Bus 1-822-E-SW02M Loads Load Name Bus Voltage Unit Rated TGB Closed Cooling Water Pump 1 4.16 kV hp 672 LC 05M Loads 480V kVA LC 07M Loads 480V kVA LC 08M Loads 480V kVA LC 09M Loads 480V kVA LC 11M Loads 480V kVA TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 21 Non-Proprietary Table 5-11. 4.16 kV Bus 1-823-E-SW01A Loads Load Name Bus Voltage Unit Rated Shutdown Cooling Pump 1

4.16 kV hp 1,000 Safety Injection Pump 1 4.16 kV hp 1,000 Charging Pump 1 4.16 kV hp 780 Component Cooling Water Pump 1A 4.16 kV hp 2,355 Essential Service Water Pump 1A 4.16 kV hp 1,248 Auxiliary Feedwater Pump A 4.16 kV hp 1,260 Essential Chiller 01A 4.16 kV hp 1,100 Cooling Tower Fan 1A 4.16 kV hp 900 LC 01A Loads 480V kVA MCC 33M Loads 480V kVA Table 5-12. 4.16 kV Bus 1-823-E-SW01C Loads Load Name Bus Voltage Unit Rated Safety Injection Pump 3 4.16 kV hp 1,000 Containment Spray Pump 1 4.16 kV hp 1,000 Component Cooling Water Pump 2A 4.16 kV hp 2,355 Essential Service Water Pump 2A 4.16 kV hp 1,248 Essential Chiller 02A 4.16 kV hp 1,100 Cooling Tower Fan 2A 4.16 kV hp 900 LC 01C Loads 480V kVA TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 22 Non-Proprietary 5.2.7.3. 13.8 kV Bus Loads (Division II)

Table 5-13. 13.8 kV Bus 1-821-E-SW01N Loads Load Name Bus Voltage Unit Rated Reactor Coolant Pump 1B 13.8 kV hp 13,500 Reactor Coolant Pump 2B 13.8 kV hp 13,500 LC 01N Loads 480V kVA LC 02N Loads 480V kVA LC 03N Loads 480V kVA Table 5-14. 13.8 kV Bus 1-821-E-SW02N Loads Load Name Bus Voltage Unit Rated Condensate Pump B 13.8 kV hp 4,600 Condensate Pump C 13.8 kV hp 4,600 Feedwater Booster Pump B 13.8 kV hp 5,000 Startup Feedwater Pump 13.8 kV hp 2,681 Circulating Water Pump B 13.8 kV hp 4,357 Circulating Water Pump D 13.8 kV hp 4,357 Circulating Water Pump F 13.8 kV hp 4,357 LC 04N Loads 480V kVA LC 06N Loads 480V kVA Cooling Tower Fan Group Loads Load Group 1 480V kVA Load Group 2 480V kVA Load Group 3 480V kVA Load Group 4 480V kVA Chlorination Loads (Future)

TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 23 Non-Proprietary Load Name Bus Voltage Unit Rated Load Group 1 480V kVA 5.2.7.4. 4.16 kV Bus Loads (Division II, Trains B and D)

Table 5-15. 4.16 kV PNS Bus 1-822-E-SW01N Loads Load Name Bus Voltage Unit Rated Central Chiller 3 4.16 kV hp 1,100 Central Chiller 4 4.16 kV hp 1,100 Central Chilled Water Pump 2 4.16 kV hp 500 LC 10N Loads 480V kVA LC 12N Loads 480V kVA Table 5-16. 4.16 kV Bus 1-822-E-SW02N Loads Load Name Bus Voltage Unit Rated TGB Closed Cooling Water Pump 2 4.16 kV hp 672 LC 05N Loads 480V kVA LC 07N Loads 480V kVA LC 08N Loads 480V kVA LC 09N Loads 480V kVA LC 11N Loads 480V kVA LC 15N Loads 480V kVA LC 16N Loads 480V kVA LC 17N Loads 480V kVA Table 5-17. 4.16 kV AAC Bus 1-822-E-SW03N Loads Load Name Bus Voltage Unit Rated LC 19N Loads 480V hp TS TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 24 Non-Proprietary Table 5-18. 4.16 kV Bus 1-823-E-SW01B Loads Load Name Bus Voltage Unit Rated Shutdown Cooling Pump 2

4.16 kV hp 1,000 Safety Injection Pump 2 4.16 kV hp 1,000 Charging Pump 2 4.16 kV hp 780 Component Cooling Water Pump 1B 4.16 kV hp 2,355 Essential Service Water Pump 1B 4.16 kV hp 1,248 Auxiliary Feedwater Pump B 4.16 kV hp 1,260 Essential Chiller 01B 4.16 kV hp 1,100 Cooling Tower Fan 1B 4.16 kV hp 900 LC 01B Loads 480V kVA MCC 33N Loads 480V kVA Table 5-19. 4.16 kV Bus 1-823-E-SW01D Loads Load Name Bus Voltage Unit Rated Safety Injection Pump 4 4.16 kV hp 1,000 Containment Spray Pump 2 4.16 kV hp 1,000 Component Cooling Water Pump 2B 4.16 kV hp 2,355 Essential Service Water Pump 2B 4.16 kV hp 1,248 Essential Chiller 02B 4.16 kV hp 1,100 Cooling Tower Fan 2B 4.16 kV hp 900 LC 01D Loads 480V kVA TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 25 Non-Proprietary

6.

ANALYSIS 6.1.

Steady-State Load Flow Analysis Steady-state load flow analysis determines the voltage, voltage angle, active power, and reactive power in the power plant.

The load flow analysis is to check the undervoltage and overvoltage of all buses during startup, normal operation, unit trip with LOCA, hot standby, SBO, LOOP with LOCA, and no load condition (as an extreme case of light load). The analysis also provides the necessary information to determine or verify the following:

The operating voltage at the MV switchgears, LC buses, and MCC buses Setpoint of undervoltage relay of 13.8 kV and 4.16 kV switchgears Percent impedance (%Z) and tap rating of transformer Other data for power system analysis 6.1.1 Acceptance Criteria The acceptance criteria for load voltage variation on continuous operation basis are +/-10 percent of the rated voltage at the equipment terminals.

Considering voltage drops across the cables between the buses and load terminals, different voltage ratings of motor loads, and transformer voltage restriction, the acceptance criteria for bus voltage variations are calculated as Table 6-1.

Table 6-1. Acceptance Criteria for Bus Voltage Variation at the Steady-state Equipment Nameplate Voltage (kV)

Acceptance Criteria 1~4)

Remark 13.8 kV Switchgear 13.8 4.16 kV Switchgear 4.16 480V LC or MCC 0.48 TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 26 Non-Proprietary 6.1.2 Analysis Result The results of load flow analysis show that the operating voltages at the MV switchgear, LC, and MCC buses are within the acceptable voltage limit at all loading conditions with maximum or minimum grid voltage. The operating voltages in heavy loading conditions with minimum grid voltage are summarized in Table 6-2 and 6-3. The operating voltages in no load condition (as an extreme case of light load) with maximum grid voltage are summarized in Tables 6-4 and 6-5.

TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 27 Non-Proprietary Table 6-2. Minimum operating Voltage Summary of Non-Class 1E Buses (Unit: %)

Case Case 1: Normal operation from UAT Case 2: Startup from UAT Case 3: Unit trip coincident with LOCA from UAT Case 4: Hot stand-by from UAT Case 5: Unit trip coincident with LOCA from SAT Case 6: Hot stand-by from SAT Case 7: SBO from AAC GTG Case 8: LOOP coincident with LOCA Table 6-3. Minimum operating Voltage Summary of Class 1E Buses (Unit: %)

Case Case 1: Normal operation from UAT Case 2: Startup from UAT Case 3: Unit trip coincident with LOCA from UAT Case 4: Hot stand-by from UAT Case 5: Unit trip coincident with LOCA from SAT Case 6: Hot stand-by from SAT Case 7: SBO from AAC GTG Case 8: LOOP coincident with LOCA TS TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 28 Non-Proprietary Table 6-4. Maximum operating Voltage Summary of Non-Class 1E Buses (Unit: %)

Case Case 1: No load operation from UAT Case 2: No load operation from SAT Table 6-5. Maximum operating Voltage Summary of Class 1E Buses (Unit: %)

Case Case 1: No load operation from UAT Case 2: No load operation from SAT 6.2.

Short-Circuit Current Analysis The short-circuit current analysis verifies that bus withstand ratings and circuit breaker interrupting ratings for all equipment are adequate for the maximum fault current.

6.2.1 Acceptance Criteria Circuit breakers for MV switchgears, 480V LCs, and 480V MCCs are selected to operate properly for continuous current and to withstand at the maximum short-circuit current.

The acceptance criteria for short-circuit current at the buses of different voltage levels are as follows:

TS TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 29 Non-Proprietary Table 6-6. Acceptance Criteria for Bus Short-circuit Current Circuit Breaker Acceptance Criteria Interrupting Rating (kA) (rms, sym)

Closing and Latching Amperes (kA) (peak) 13.8 kV 50 130 4.16 kV 50 130 480V LC 30/501) 480V MCC 30/421),2)

Notes

1) Interrupting rating value of the LC or MCC can be selected from the two values based on short-circuit current value.

2) Required interrupting rating of the MCC is 42 kA based on calculation, but 50 kA rating breaker is actually used for the commercial availability and maintenance as stated in Subsection 5.2.5.4.

6.2.2 Analysis Result The results of the short-circuit calculations under all operating conditions are summarized in Tables 6-7 and 6-8.

The short-circuit calculation shows that the maximum short-circuit currents at the MV switchgears, 480V LCs, and 480V MCCs in all operating conditions are within the closing and latching and interrupting rating of circuit breaker.

Table 6-7. Short-Circuit Current Summary of Non-Class 1E Buses at All Operating Conditions (Unit: kA)

CASE Case 1 :Normal operation from UAT1)

Case 2: Start-up from UAT Case 3: Unit trip coincident with LOCA from UAT Case 4: Hot stand-by from UAT Case 5: Unit trip coincident with LOCA from SAT Case 6: Hot stand-by from SAT Case 7: SBO from AAC GTG TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 30 Non-Proprietary Notes

1) From conservative approach, parallel operation of an EDG with grid power is considered.

Table 6-8. Short-Circuit Current Summary of Class 1E Buses at All Operating Conditions (Unit: kA)

CASE Case 1 :Normal operation from UAT1)

Case 2: Start-up from UAT Case 3: Unit trip coincident with LOCA from UAT Case 4: Hot stand-by from UAT Case 5: Unit trip coincident with LOCA from SAT Case 6: Hot stand-by from SAT Case 7: SBO from AAC GTG Notes

1) From conservative approach, parallel operation of an EDG with grid power is considered.

6.3.

Motor Starting Analysis The motor starting analysis provides reasonable assurance of the stable operation of the onsite power system by analyzing the voltage drop during starting of the large motors.

The motor starting study performs voltage drop analysis of the onsite ac power system during the starting of large motors and verifies whether the starting of large motors are successfully done and the terminal voltages are maintained within the allowable voltage limits during the starting conditions of the large motors.

6.3.1 Acceptance Criteria The required motor minimum voltages during starting of the large motors are 80 percent of motor rated voltage for non-Class 1E motors and 75 percent for Class 1E motors at the equipment terminals.

Considering voltage drops across the cables between the buses and load terminals, and different starting and running voltage requirements of motor loads, the acceptance criteria for bus voltage variations during the starting of large motors are calculated as Table 6-9.

TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 31 Non-Proprietary Table 6-9. Acceptance Criteria for Bus Voltage Variation during the Starting of Large Motors Equipment Nameplate Voltage (kV)

Acceptance Criteria 1,2)

Remark 13.8 kV non-Class 1E Switchgear 13.8 4.16 kV non-Class 1E Switchgear 4.16 4.16 kV Class 1E Switchgear 4.16 480V non-Class 1E LC or MCC 0.48 480V Class 1E LC or MCC 0.48 6.3.2 Analysis Result The results of the motor starting analysis under all operating conditions are summarized in Tables 6-10 and 6-11.

The motors selected to evaluate allowable minimum bus voltages under starting conditions of the large motors are as follows:

Reactor coolant pump (RCP) for 13.8 kV Component cooling water pump for 4.16 kV As shown in Tables 6-10 and 6-11, the results of motor starting analysis demonstrate the selected large motors are successfully started and most of the bus voltages are maintained within the allowable minimum voltage limit during the large motor starting conditions under various plant operating modes.

In some cases (Cases 9, 10, 15, and 16), minimum required voltage at equipment terminal can be achieved by reducing feeder cable voltage drop from [ ]TS % to [ ]TS % (of bus nominal voltage).

TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 32 Non-Proprietary Table 6-10. Motor Starting Summary of Non-Class 1E Buses (Unit: %)

CASE Case 1: Normal operation from UAT (CCW PP1A)

Case 2: Normal operation from UAT (CCW PP1B)

Case 3: Startup from UAT (RCP 1A)

Case 4: Startup from UAT (RCP 1B)

Case 5: Startup from UAT (CCW PP1A)

Case 6: Startup from UAT (CCW PP1B)

Case 7: Unit trip coincident with LOCA from UAT (CCW PP1A)

Case 8: Unit trip coincident with LOCA from UAT (CCW PP1B)

Case 9: Hot standby from UAT (RCP 1A)

Case 10: Hot standby from UAT (RCP 1B)

Case 11: Hot standby from UAT (CCW PP1A)

Case 12: Hot standby from UAT (CCW PP1B)

Case 13: Unit trip coincident with LOCA from SAT (CCW PP1A)

Case 14: Unit trip coincident with LOCA from SAT (CCW PP1B)

Case 15: Hot standby from SAT (RCP 1A)

Case 16: Hot standby from SAT (RCP 1B)

Case 17: Hot standby from SAT (CCW PP1A)

Case 18: Hot standby from SAT (CCW PP1B)

Table 6-11. Motor Starting Summary of Class 1E Buses (Unit: %)

CASE Case 1: Normal operation from UAT (CCW PP1A)

Case 2: Normal operation from UAT (CCW PP1B)

Case 3: Startup from UAT (RCP 1A)

Case 4: Startup from UAT (RCP 1B)

Case 5: Startup from UAT (CCW PP1A)

TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 33 Non-Proprietary Case 6: Startup from UAT (CCW PP1A)

Case 7: Unit trip coincident with LOCA from UAT (CCW PP1A)

Case 8: Unit trip coincident with LOCA from UAT (CCW PP1B)

Case 9: Hot standby from UAT (RCP 1A)

Case 10: Hot standby from UAT (RCP 1B)

Case 11: Hot standby from UAT (CCW PP1A)

Case 12: Hot standby from UAT (CCW PP1B)

Case 13: Unit trip coincident with LOCA from SAT (CCW PP1A)

Case 14: Unit trip coincident with LOCA from SAT (CCW PP1B)

Case 15: Hot standby from SAT (RCP 1A)

Case 16: Hot standby from SAT (RCP 1B)

Case 17: Hot standby from SAT (CCW PP1A)

Case 18: Hot standby from SAT (CCW PP1B) 6.4.

Harmonic Analysis Harmonics in the electrical system are an important indicator of poor power quality. They cause overheating in electrical components and can damage sensitive equipment. Harmonic analysis is typically conducted as part of a power quality study to identify the source of harmonics and develop a plan for corrective action.

The objective of harmonic analysis is to calculate individual and total harmonic distortion and to confirm that the result of harmonic analysis is within acceptable limits.

6.4.1 Acceptance Criteria Simulations are performed to identify expected harmonic levels under various plant operating modes and source conditions. Variations in waveform (harmonic distortion) in the onsite power system and its components during any mode of plant operation are confirmed not to degrade the performance of any safety system load.

Acceptance criteria for harmonic analysis are as follows:

Table 6-12. Acceptance Criteria for Harmonic Analysis Bus Voltage Individual Voltage Distortion (%)

Total Voltage Distortion (%)

69 kV and below 3.0 5.0 TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 34 Non-Proprietary 6.4.2 Analysis Results The harmonic analysis is summarized in Tables 6-13 and 6-14, and the total voltage harmonic distortion at the Class 1E buses meets the acceptance criteria of Subsection 6.4.1. It should be noted, however, that harmonic sources are conservatively assumed as six-pulse models because there are no harmonic data of suppliers. Therefore, the harmonic analysis should be performed and reviewed with actual data in the detailed design phase.

Table 6-13. Maximum Total Harmonic Distortion in Non-Class 1E Buses (Unit: %)

CASE Case 1: Normal operation from UAT Case 2: Startup from UAT Case 3: Unit trip coincident with LOCA from UAT Case 4: Hot standby from UAT Case 5: Unit trip coincident with LOCA from SAT Case 6: Hot stand-by from SAT Case 7-1: SBO from AAC GTG on Division I Case 7-2: SBO from AAC GTG on Division II Table 6-14. Maximum Total Harmonic Distortion in Class 1E Buses (Unit: %)

CASE Case 1: Normal operation from UAT Case 2: Startup from UAT Case 3: Unit trip coincident with LOCA from UAT Case 4: Hot standby from UAT Case 5: Unit trip coincident with LOCA from SAT Case 6: Hot stand-by from SAT TS TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 35 Non-Proprietary CASE Case 7-1: SBO from AAC GTG on Division I Case 7-2: SBO from AAC GTG on Division II 6.5.

Bus Transfer Analysis Bus transfer is a process of transferring bus loads from one power source to another. During bus transfer, resultant voltage and frequency decay may cause excessive transient torque so that mechanical damage occurs in the motor, the coupling to the load, or the load itself.

The purpose of bus transfer is to maintain process continuity and to supervise source transfer to avoid causing any damage to the motors, couplings, and connected loads. In this section, the bus transfer procedure and results are reviewed and evaluated to provide reasonable assurance that the results are within acceptable limits.

The loading and source condition, before and after a bus transfer, assumed in the bus transfer analysis is unit trip coincident with LOCA from UAT and unit trip coincident with LOCA from SAT, respectively.

Major factors and assumptions used for bus transfer analysis are provided in Subsection 5.1.8.

6.5.1 Acceptance Criteria The bus transfer occurs within a period of 10 cycles or less.

The maximum phase angle between the motor residual V/Hz vector and the system equivalent V/Hz vector does not exceed 90 degrees.

The resultant V/Hz between the motor residual V/Hz phasor and the incoming source V/Hz phasor at the instant of transfer or reclosing does not exceed 1.33 pu V/Hz on the motor rated voltage and frequency basis.

Notes: If the condition before a fast bus transfer does not satisfy above criteria, the bus transfer will be implemented by a residual voltage bus transfer.

6.5.2 Analysis Results Results of the following three items are reviewed:

Voltage profile of load bus during bus transfer Voltage phase angle between load bus and new source during bus transfer V/Hz between load bus and new source during bus transfer The resultant V/Hz and phase angle values, calculated at the point of the new source breaker closure, are TS TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 36 Non-Proprietary monitored to confirm they are within the established maximum 1.33 pu V/Hz and 90 degrees.

As indicated in Table 6-15, the buses of which the analysis results are within the acceptance limits are expected to be transferred by fast bus transfer given the postulated loading condition, and the other buses are expected to be transferred by residual bus transfer.

It should be noted, however, that the major input data that affect the analysis results, such as characteristics of relay devices, motors, different voltage phase angles between two offsite sources, and accident scenarios, are assumed based on the reference plant data of the APR1400. Therefore, the bus transfer analysis should be performed and reviewed with refined data in the detailed design phase.

Table 6-15. Transient Analysis Summary of Bus Transfer TS

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 37 Non-Proprietary

7.

CONCLUSIONS The load flow analysis shows that the operating voltages at the MV switchgears, 480V LCs, and 480V MCCs for all loading conditions are maintained within the acceptable voltage limit (+/- 10 percent of rated voltage at the equipment terminals).

The short-circuit analysis shows that the maximum short-circuit currents at MV switchgears, 480V LCs, and 480V MCCs for all operating conditions are within the closing and latching, and interrupting ratings of the circuit breakers.

The motor starting analysis shows that the selected large motors are successfully started and most of the bus voltages are maintained within the allowable minimum voltage limit during the large motor starting conditions under various plant operating modes. In some cases (Cases 9, 10, 15, and 16), minimum required voltage at equipment terminal can be achieved by reducing feeder cable voltage drop.

The harmonic analysis shows that the individual and total voltage harmonic distortion at each Class 1E bus meets the respective acceptance criteria (3 percent individual voltage distortion, 5 percent total voltage distortion).

The bus transfer analysis shows that fast bus transfer is expected to be allowed for some buses under the postulated operating condition. For the other buses, for which fast bus transfer is blocked by the fast bus transfer relays (25F), residual voltage bus transfer will be performed instead of fast bus transfer. In detailed design phase, transfer strategies of buses, such as fast transfer and residual voltage transfer, will be reestablished and reassessed based on actual equipment data.

Onsite AC Power System Analysis APR1400-E-E-NR-14001-NP, Rev.3 KEPCO & KHNP 38 Non-Proprietary

8.

REFERENCES

1.

APR1400-K-X-FS-14002, APR1400 Design Control Document, Tier 2, Rev. 1, KEPCO and KHNP, [March 2017].

2.

10 CFR 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants.

3.

10 CFR 21, Reporting of Defects and Noncompliance.

4.

ASME NQA-1, Quality Assurance Requirements for Nuclear Facility Applications, American Society of Mechanical Engineers, 2008.

ML18067A856

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