ML18019A852
| ML18019A852 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 06/08/1982 |
| From: | Davidson D Cleveland Electric Illuminating Co |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9206170290 | |
| Download: ML18019A852 (3) | |
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- 11 Hr. A. Schvenccr, Chief.
. _ Licensing lr*nch "°. 2.
D:lviston of i.tcenUnit.
- u. ;S *. Nuclear Regulatory Co111dsdon
- Washington, D. c.
20S5S
Dear Hr. Schvencer:
Perry Nuclear ;over flant Doc~t No,.* so~440; 50~441 so conftniator:,.Jteti -
Undervolta&e.Pfotectton.
Further revi~w a11d analysis of the Class IE unden-oltage*protection1che11e has been conducted iii respe>nlie t~ FSAR *qu~ation 430.17*.
A var~~ty of
- grid conditions were evaluated and computer daulaUoiie u1ed to etudy the !Jfff!cts of the 31,s 'itv ayit:em gr*d voltages in relation to the Clase IE bue voltage..Voltage,natyses in both.steady atute and :
transient. condition were perfcirnied.
Tt1c acc~l'tance criteria for t_he.ClaBS 1E
- bua volta1es "as baaed on the followilig purchase specificatfon requirenaenta:
- t..MotQrs are capable of starting fl'.om rea_t and accelerating their specified load with 75%
of rated nameplate voltage e~i&t{ng(dtiring acceleration) at the motor tenninala~
- 2.
Motors are capable of. delivering their rated horsepower continuously. when. the. terminal voltage is+/- *0% of rated voitage.
- 3.
Hc.,t;ors are capab~:e of deltver{11g _their rated full load tprque at, 70% pf.rated *v~ltage *for infrequent
. five ml11ute Jnt~rval~.
- 4.
Ho tors are ~apable ot starttm~,dth 110% of rate'd.
~:voua*se 1i'i>pilea *aa: the motor*fenitnda~ * **
Rev.lev of aU steady *state cas~s. shows that the Cla88 1 E busea sust:aine~
- n6 dcgradati<>n Qf voltage greater tiian lo% duriiig o~et~tion *t111der hll load,
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- unit trip and LQCA.aod~li. i"'9 tranalent.*cu.e* ~- *a *re.**... *
- aevt!ire t:eilt :o:,* 'the auJclliat,.'ayateia~ 11.!~),tl'tb' *c:~* *,µppor.t' *(.itonraf ~1~*1*.
- durin1 tli* *tarting J>f ~tor* *. *ln only oi,,d,f"t~tl caj,, *~~tlld: '<
0 cHd_.the'voltage.on. th~ Cl*** lEblltie.~ MC~dl!prt!l~~d beiow*ttae.0,5% J~~l for* atarttna Jaotorli.
Ira thh worat. came aceilado Perry vaa c*af,derecl tcf be offline 'ta\\'. 'startup or juat :trlpped:m~e 111~~ _other' 'iiaj'*qr:.... ~..,tt..,
~its of the. CEl.syateti of0il)e and *a feedvater p... p(SOOO.-,) "* _Ul)ually started concurrent with receipt: c,f a LOCA aignal and the *-ltarieoui starttn1 ot *the. zero second LOCA 1o~da(21too *KW>. ** :1.; thiil c*** the voltaae decays to 73%>ofmotor rate.cLvoltage..
In evaluation of this atudy, thl! auxUiary-ayatem provide~ 1uftict1nt and reUable voltage riecea~aryJor litarting*Claiia I~ 11e>tora in*au ca***
except the highly improl,able:aequence deacribed above.
In order to. provide further assurance of required ClaH IE operation even undf!r the IIOU adverse conditions, two levels of undervoltage protection will be provided.
for the Class l E buses.
The first level of protection is. provided.to trip the offaite power
- source breakers arid'start and load* the diesel generator* in the caae of a lose of offsite power.
A,et of widervoltage relays vtll be provided for each ClaH IE bus, set to trip: at 86% of 110tor rated voltaae. The undervoltage relays, fol1ovtn1 a l second fixed tliie delay, wUi initiate the neceB&ary logic to r,onnect the ClaH lE buaea to the dteael generaton.
A LOCA signal initiates a diesel generator start signal, however, the.
diesel geriei'ator breaker ia not closed unless an undervoltage condition.
exists~. Hence, even if a LOCA aignal ts rec.eived during the l second time delay vhen voltage ta 86%, a system performance'within regulatory re-quirements is still met.
A short time delay *111 required for this level of protection to allow time for fault cle~rtng operations to attempt to return the system to an acceptable level.
The second level of undervoltage.protection will be provided to.insure the off site power source does not degrade to.a level. which* could jeopardize starting of Class lE motors in an adverie situation.
A second set of undervoltage relays will be provided for each ClaH lE bus, set to trip at 96% of motor rated voltage.* The undervoltage relays will energhe two separate time delay relays.
The first time delay relay will initate undervoltage alarms apd a diesel generator start signal after 15 secon~s. The second tilne delay, will be set for approxlmately 5 n1inutes at which time the offsite source breakers: will be tripped and tile diesel* gener11tor loaded on the bus~.*.The five minute timer wtU also insure against motor overheating between 90% and 86% voltage *. The 1110tors purchased for Perry have perfol'liance characteristics.11uch that they can operate for. !nfrequerat 5 minute pedoda:at' 70% 'voltage.*..,,..
This und~TV~ltage schemede(f.Cl'.'ibed above is presently being incorporated into O!,lr ~eli1BR*
'J,'estlng will al&O!be coriduct:ed to inilure.correct.reJay 11,tttngs.
- Th~ Unal :design and. settings viH be esi:abUshed after a review
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