24.019.6

Urp(p-e) en KV = 19.40Urp(p-p) en KV = 33.60

19.40 Kv 33.60 Kv

Ue2 en p.u = 2.9 Ue2 en p.u = 2.5 2.6Up2 en p.u = 4.35 Up2 en p.u = 3.75 4.34Uet en p.u = 3.38 Uet en p.u = 2.88 3.00Upt en p.u = 5.008 Upt en p.u = 4.258 4.995Uet en Kv = 66.136 Uet en Kv = 56.338 58.788U K 98 12 U K 83 43 9 88

Overvolteges originating from station 1

Energization and re-energization

Ue2 en p.u =Up2 en p.u =Uet en p.u =Upt en p.u =Uet en Kv =U K

STEP 1: Determination of the representative overvoltages (Urp)

Kv phase-to-phase

Phase-to-phase : Urp(p-p) =

Us =Power-frecuency Voltage

Temporary overvoltages

Earth faults

Load rejection 1.4

Kv (crest)

Urp(p-e) en KV = 19.40Earth-fault factor: k = 1.4

Max. Overvoltage en p.u =

1.0 p.u =

Resulting representative overvoltegesPhase-to-earth : Urp(p-e) =

Slow-front overvoltages

Overvolteges originating from station 2

Re-energization Capacitorswitching

Upt en Kv = 98.127 Upt en Kv = 83.43 97.88

No YesPhase-to-earth : Urp = Ups = 45 Kv Urp(p-e) = 45 Kv Urp(p-e) = 45 KvPhase-to-phase : Urp = 2Ups = 90 Kv Urp(p-p) = 97.88 Kv Urp(p-p) = 90 Kv

5445 Upl en Kv =

For other equipment

With or without capacitor switching Capacitor switching at station 2Uet > Ups Upt > 2 Ups

For Line entrance equipment

Arresters at line entrance and near transformers : Ups en Kv =

Upt en Kv =

Fast-front overvoltages Evaluated in step 2

a) Ups/Ue2 = 0.79 a) 2Ups/Up2 = 1.06 1) Ups/Ue2 = 0.92 1) 2Ups/Up2 = 1.225b) Ups/Ue2 = 0.92 b) 2Ups/Up2 = 1.22 2) Ups/Ue2 = 0.88 2) 2Ups/Up2 = 1.06

a) Kd = 1.08 a) Kd = 1.00 0 1) Kcd = 0.00b) Kd = 0.00 b) Kd = 0.00 1.06 2) Kcd = 1.00

Kcd = 1.08 1.080.00

Ucw = Kcd x Urp Ucw = Kcd x Urp 48.38 1) Ucw = 0.00Ucw (KV)= 48.38 Ucw (KV)= 90 0.00 2) Ucw = 97.88

a) From reenergization at station 2 1) With capacitor switching at station 2b) From capacitor swithing at station 2 2) Without capacitor switching at station 2

1) kcd =2) kcd =

1) Kcd =2) Kcd =

2) Ucw =

Retained value :

1) Ucw =

Retained value :

Phase to phase

1Temporary overvoltage

Phase to earth en Kv : Ucw = Kc x Urp =Phase to phase en Kv: Ucw = Kc x Urp =

Kc Factor =

Phase to phase Phase to earthPhase to earth

19.4033.6

STEP 2: Determination of the coordination withstand voltages (Ucw)

Slow-front overvoltage Deterministic metod used = Kcd factor

Line entrance equipement (external insulation only) Other equipment

Parameter A = 900Span length Lsp = 100 mOutage rate Rkm = 0.03 Km/yearAcceptable failure rate Ra = 0.0067 Years

Arrester Lightning protection level : Upl = 54 KvMax. Separation from internal insulation: L = 8 m La = 223.33 mMax. Separation from external insulation: L = 15 m

Internal insulation : Ucw 76.27 KvExternal Insulation : Ucw 95.75 Kv

n = 1n = Numero de lineas conectadas a la Subestacion

performance requiredData from experience

Fast-front overvoltages Simplified statical method used

aspplcw LL

LnAUU *

Internal insulation : Ks =External insulation : Ks =

Internal insulation : Urw = Ucw x KsExternal insulation : Urw = Ucw x Ks x Ka

Kv Kv Kv Kv

K KI l i

Internal Insulation

ExternalI l i

22.31Internal

Insulation38.64

External

Insulation

Phase to earth Phase to phase Phase to earth Phase to phase

Line entrance

I l i

87.71External Insulation

External Insulation

87.71

Temporary overvoltage withstand Switching impulse withstand Lighting impulse withstand

ExternalI l i

Internal Insulation

External

equipment

Phase to earth Phase to phase

Line entranceequipment

Internal

Atmospheric correction factor Altitude H = 3570 m

Step 3 : Determination of the required withstand voltages (Urw)

Safety factor 1.151.05

Power - frequency withstand Switching impulse withstand Lighting impulse withstand

Phase to earth Phase to phase Phase to earth Phase to phase Phase to earth Phase to phase

m = 1

Ka = 1.5497

m = 0.5

Ka = 1.2449

8 1 146 44

m = 1

Ka = 1.550

m = 1

Ka = 1.5497

Required withstand voltages

Kv Kvkv kv kv kv

1) kv 1) kv2) kv 2) kv

1) With capacitor switching at station 21) kv 1) kv 2) Without capacitor switching at station 22) kv 2) kv

m =H =Ka =

3570

25.36 43.92

InternalInsulation

ExternalInsulation

55.630.00

Otherequipment

78.710.00

Insulation Insulation Insulation

Insulation

Otherequipment

Internal

155.80

0.00112.56External

155.80Insulation

1.4197

78.71 146.44

0.8

Insulation0.00

159.27

8150.

Hm

a eK

External insulation : External insulation :- phase to earth 0.6 + Urw/8500 - phase to earth 1.3- phase to phase 0.6 + Urw/12700 - phase to phase 1.05 + Urw/9000

Internal insulation : Internal insulation :- phase to earth 0.5 - phase to earth 1.1- phase to phase 0.5 - phase to phase 1.1

- phase to earth - phase to earth - phase to earth - phase to earthKv 1) Kv Kv 1) Kv

2) Kv 2) Kv- phase to phase - phase to phase

Kv - phase to phase Kv - phase to phase1) Kv 1) Kv2) Kv 2) Kv

- phase to earth - phase to earth1) Kv 1) Kv

Step 4 : Conversion to withstand voltages normalized for range I

Conversion of switching impulse withstandVoltages to lightning impulse

withstand voltagesConversion of switching impulse withstandVoltages to short-duration power.frequency

withstand voltagesConversion factorsConversion factors

Line entranceequipment

Internal Insulation

otherequipment

External insulation External Insulation

61.19

otherequipment

0.0097.56

External Insulation47.96 102.33 102.33

Internal Insulation27.82

0.00 0.00156.15

0.00170.05

Line entranceequipment

47.96

89.55

External insulation

1) Kv 1) Kv2) Kv 2) Kv- phase to phase - phase to phase1) Kv 1) Kv2) Kv 2) Kv

0.00

0.0056.28 123.82

0.00

0.00

61.1927.82

Frecuencia Fase - TierraIndustrial Fase - Fase

Impulso de Fase - TierraManiobra Fase - FaseImpulso Fase - Tierra

Atmosferico Fase - Fase

* 70 kV Para tensiones de soportabilidad de corta duracion a frecuencia industrial * 170 kV Para tensiones de soportabilidad al impulso atmosferico

Para el aislamiento de equipos en S.U. 22.9 kV se selecciona las siguientes tensiones de soportabilidad

RESUMEN DE LAS TENSIONES DE SOPORTABILIDAD REQUERIDAS

Urw(s) Urw22.31 0.00

de maniobra y rayo Urw(s)25.36

Urw Urw(s)

155.80156.15155.80

KV r.m.s paraFrecuencia industrial

Kv Pico para impulsosAislamiento externo

Equipos entradade linea Otros equipos

78.71146.4443.92

47.9689.55

102.33

56.2897.560.00

87.71 0.00112.5638.64

155.80

43.92159.27

Aislamiento interno

(1) (1) (1)0.00

Urw25.36 0.00

87.71 123.82 De acuerdo a la tabla 2 de la Norma IEC 60071-1 se selecciona valores normalizados de aislamiento

que cubriran cualquier aislamiento externo e interno fase-fase y fase-tierra.

155.80

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