UHV Equipment Requirements Anton Janssen Report 4.1 on behalf of WG A3.22 UHV Equipment Requirements Anton Janssen

CIGRÉ WG A3.22 Scope: Review state-of-the art of project specific and national technical specifications for all substation equipment within scope of SC A3, at voltages exceeding 800 kV. Recommend future specifications and standardizations for 1100 and 1200 kV equipment and provide, to IEC TC 17, technical background information. General information in Report 3.1, and the presentation of Report 3.1, by the convenor Hiroki Ito. UHV circuit-breaker information in Report 4.1.

TRV envelope MOSA Uc/t2 RV= kpp*Ur 2/3 U1=0.75*RV U1/t1 Uc=kaf*U1/0.75 t1=U1/RRRV t2=?*t1 U1/t1 ITRV RRRV td

Kpp Kpp depends on X0/X1 ratio X0/X1 for transformers << 1.0 X0/X1 OH-lines >> 1.0 UHV: long OH-lines, heavy transformers -> In UHV substations X0/X1 less than at EHV -> Kpp = 1.2 instead of 1.3

RRRV UHV OH-lines:. large diameter conductor bundles RRRV UHV OH-lines: * large diameter conductor bundles * heavy sub-conductors * no bundle contraction before interruption for first and last clearing pole Z < 330 Ω At 50 kA, 50 Hz rating (n is number of OH-lines): for T100 with n>3 RRRV< 2 kV/µs for T60 with n>1 RRRV< 3 kV/µs

Kaf, t2, t3 At UHV less damping expected, but limited experience, therefore proposed: for T100 Kaf from 1.4 to 1.5 T60 1.5 T30 1.54 T10 1.76 (covering LLF) t2 calculated by simplified model and compared with TEPCO-network, proposed: for T100 t2 from 4*t1 to 3*t1 T60 t2 from 6*t1 to 3*t1 (covering LLF~IEEE) for T30, T10 t3 = Uc/RRRV

ITRV. Applicable to AIS and MTS (HGIS) substations ITRV * Applicable to AIS and MTS (HGIS) substations * Surge impedance of busbars and bays for instance 263 Ω to 325 Ω (Powergrid 1200 kV) * First reflections: ti = 1.5 μs (Powergrid 1200 kV) * For 260 Ω ITRV covered by SLF without tdL * What about 325 Ω? * What about ITRV traveling waves at both sides?

ITRV (PowerGrid 1200 kV)   80 m 240 m 160 m 60 m 120 m > 40 m

SLF, LLF. Z = 330 Ω. tdL = 0. 5 µs. LLF covered by T60, T30, T10 with: SLF, LLF * Z = 330 Ω * tdL = 0.5 µs * LLF covered by T60, T30, T10 with: T60 t2 = 3*t1 T60 kpp = 1.2, kaf = 1.5 T30 kpp = 1.2, kaf = 1.54 T10 kpp = 1.2, kaf = 1.76

TLF. new specification ~ IEEE draft C37. 06 TLF * new specification ~ IEEE draft C37.06 * TLF-current from R10 series (close to T30/T10) * t3 = k x Ur with k = 6, based on information of I 0.21 surge cap. of some UHV transformers * kpp = 1.3, kaf = 0.9*1.7 * 1.3*0.9*1.7 < 1.2*1.76 (T10)

Out-of-Phase. at UHV large out-of-phase angles possible: 180° Out-of-Phase * at UHV large out-of-phase angles possible: 180° * with low kpp, at 180°, first pole RV ~ 2.0 pu * Iop and RRRV are proportional to RV * Uc is proportional to RRRV and line length * at 105º: RV, Iop, RRRV and Uc will be 20% lower * not enough information about probability, Iop and kaf in service

Impact of MOSA on Uc

Impact of MOSA on Uc. there is a clear impact of UHV MOSA on Uc Impact of MOSA on Uc * there is a clear impact of UHV MOSA on Uc * variation in MOSA characteristics and application require to apply some margin above SIPL * another margin is required to be specified between Uc and SIPL plus margin * due to both margins effect of MOSA on specified Uc for T100, T60 is nihil or small * due to load side part of TRV at LLF and TLF effect of MOSA on Uc for T30, T10 is nihil or small

Impact of opening resistors Impact of opening resistors * opening resistors advantageous to further reduce switching surges * Opening resistors positive effect on Uc and RRRV for both main and auxiliary contacts * Caution for capacitive current and OP switching, in some cases * Application and specification very user specific

Thank you for your attention Thank you for your input!! WG A3.22: Thank you for your attention Thank you for your input!!