surge arrester placement for substation lightning protection · surge arrester s are only mounted...

Surge Arrester Placement for Substation Lightning Protection

Qianxue [email protected]

1

2

• Introduction

• Modelling

• Results

• Conclusions

Agenda

3

Introduction

4

Introduction• Most utilities install surge arresters at both the

entrance of the substation and the terminal of the transformer.

• Due to the high installation cost of surge arresters, some utilities like Salt River Project (SRP) only install the surge arrester at the transformer side.

5

IntroductionTwo major concerns:

• Critical point • maximum recommended length of the transmission

line before an arrester needs to be applied

• Performance for different surge arrester configurations

6

IntroductionDefinition of critical pointLightning strokes are applied at different distances from the entrance point. The corresponding lightning stroke location of the maximum voltage at the entrance of the substation or the terminal of the transformer is defined as the critical point.

X ZY

7

IntroductionFour different surge arrester configurations forsubstation lightning protection are considered:• C1: No installed surge arrester on the substation • C2: Surge arresters are installed at the entrance of the

substation and at the terminal of the transformer respectively.

• C3: Surge arresters are only mounted at the entrance of the substation;

• C4: Surge arresters are installed on the terminal of the transformer.

8

Modelling

9

Modelling Fast front transient model for :

• a practical SRP 500-230 kV substation (with realfield data)

• a few spans of the 230kV transmission line

This Model is developed using PSCAD 4.6.0.

SRP denotes Salt River Project which is a utility located in Arizona.

10

Modelling Simulation procedures :Step 1. Model 230kV transmission line and the connected substation in PSCAD using the field data.Step 2. Changing the distance from the lightning stroke location to the entrance of the substation. Step 3. repeating step (2) for different protection configurations.

X ZY

0 200 400 600 800 1000

100

200

300

400

500

600

700

(d) C4- One surge arreste r on Point Z

Peak

volta

ge a

mpli

tude

(kV)

Distance to Point X (m)

UY-phase A UY-phase B

UY-phase C UZ-phase A UZ-phase B UZ-phase C

11

Results

12

C2 : surge arresters are installed at both the entrance of thesubstation and the terminal of the transformer.

0 40 80 120 160

0

200

400

0 40 80 120 160

0

200

400

0 40 80 120 1600

200

400

600

0 40 80 120 1600

200

400

600

0 40 80 120 160

0

6

12

18

0 40 80 120 160

0

6

12

18

(iii) (iii)

(ii) (ii)

(i)

Vol

tage

(kV

)

T ime (µs)

Phase A Phase B Phase C

Vol

tage

(kV

)

Time (µs)


(b) Terminal of the transformer

Ene

rgy

(kJ)

Time (µs)


(a) Entrance of the substation

(i)

Ene

rgy

(kJ)

Time (µs)


Cur

rent

(kA

)

T ime (µs)


Cur

ren

t (kA

)

Time (µs)


Arrester Voltage

Arrester Energy duties

Arrester Current

Direct stroke — Phase B is hit by the lightning stroke

Lightning stroke distance = 20m

13

Voltage-distance curves X ZY

• The voltages on phase A and phase C are far less than the voltage on phase B.

Critical Point

0 200 400 600 800 1000

200

400600800

100012001400

16001800

0 200 400 600 800 1000

100

200

300

400

500

600

700

0 200 400 600 800 1000

100

200

300

400

500

600

700

800

0 200 400 600 800 1000

100

200

300

400

500

600

700

Peak

vol

tage

am

plitu

de (k

V)



UY-phase C UZ -phase A UZ -phase B UZ -phase C

Pea

k vo

ltage

am

plitu

de (k

V)


UY-phase A UY-phase B UY-phase C

UZ-phase A UZ-phase B UZ-phase C

Peak

vol

tage

am

plitu

de (k

V)


UY-phase A UY-phase B UY-phase C UZ-phase A UZ-phase B

UZ-phase C

(b) C2- Two surge arreste r on both Point Y and Z

(c) C3- One surge ar rester on Point Y (d) C4- One surge arreste r on Point Z

(a) C1-No installed surge arreste r

Pea

k vo

ltage

am

plitu

de (k

V)



UY-phase C UZ-phase A UZ-phase B UZ-phase C

• Most critical points are the closest point to the line entrance of the substation

14

Results

28%

183%

31% 25%

194%

27% 19%

73%

19% 12%

71%

15%

15%

70%

15% 12%

85%

14% 16%

79%

16% 12%

70%

15%

UA,Y UB,Y UC,Y UA,Z UB,Z UC,Z

0

40

80

120

160

200

Um

ax

/ B

IL (%

)

CP=920 m

CP=160m

CP=920mCP=700m

CP=20 m

CP=840mCP=2 0M

CP=20m

CP=20mCP=20m

CP=20m

CP=20m

CP=2 0m

CP=20m

CP=20mCP=20m

CP=20m

CP=20mCP=20m

CP=20m

CP=20mCP=20m

CP=20m

CP=20 m


0

20

40

60

80

Um

ax

/ B

IL (%

)


0

20

40

60

80

Um

ax

/ B

IL (

%)

(a) C1 (b) C2

(c) C3 (d) C4UA,Y UB,Y UC,Y UA,Z UB,Z UC,Z

0

20

40

60

80

Um

ax /

BIL

(%

)

• Phase A and phase C voltages can only reach up to 31% of the BIL value

• Without surge arrester, the voltage at the transformer can reach up to 194% of the BIL value.

• C3 has the highest voltageat the transformer terminalamong C2, C3, C4

15

Voltage-distance curve for Phase B

0 100 200 300 400 500 600 700 800 900 1000300

600

900

1,200

1,500

1,800

UY-C1 UZ-C1 U

Y-C2

UZ-C2

UY-C3

UZ-C3 U

Y-C4

UZ-C4


Pea

k vo

ltage

am

plitu

de (k

V) 50 100 150 200 250 300

400

500

600

700

800

P2

P1

• C3: 𝑈𝑈𝑌𝑌 < 𝑈𝑈𝑍𝑍 C4: 𝑈𝑈𝑌𝑌 > 𝑈𝑈𝑍𝑍

𝑈𝑈𝑌𝑌 - voltage at theentrance of the substation𝑈𝑈𝑍𝑍 - voltage at theterminal of the transformer

C3: Surge arresters are only mounted at the entrance of the substation;C4: Surge arresters are installed on the terminal of the transformer.

16


0 100 200 300 400 500 600 700 800 900 1000300

600

900

1,200

1,500

1,800

UY-C1 UZ-C1 U

Y-C2

UZ-C2

UY-C3

UZ-C3 U

Y-C4

UZ-C4


Pea

k vo

ltage

am

plitu

de (k

V) 50 100 150 200 250 300

400

500

600

700

800

P2

P1


• 𝑃𝑃1 is the point of intersection of 𝑈𝑈𝑍𝑍 −C3 𝑎𝑎𝑎𝑎𝑎𝑎 𝑈𝑈𝑌𝑌 − 𝐶𝐶𝐶

𝑈𝑈𝑌𝑌 denotes the voltage at theentrance of the substation

𝑈𝑈𝑍𝑍 denotes the voltage at theterminal of the transformer


17


0 100 200 300 400 500 600 700 800 900 1000300

600

900

1,200

1,500

1,800

UY-C1 UZ-C1 U

Y-C2

UZ-C2

UY-C3

UZ-C3 U

Y-C4

UZ-C4


Pea

k vo

ltage

am

plitu

de (k

V) 50 100 150 200 250 300

400

500

600

700

800

P2

P1



• 𝑃𝑃2 is the point of intersection of 𝑈𝑈𝑍𝑍 −C3 𝑎𝑎𝑎𝑎𝑎𝑎 𝑈𝑈𝑍𝑍 − 𝐶𝐶𝐶




18


0 100 200 300 400 500 600 700 800 900 1000300

600

900

1,200

1,500

1,800

UY-C1 UZ-C1 U

Y-C2

UZ-C2

UY-C3

UZ-C3 U

Y-C4

UZ-C4


Pea

k vo

ltage

am

plitu

de (k

V) 50 100 150 200 250 300

400

500

600

700

800

P2

P1


• 𝑈𝑈𝑌𝑌 − C𝐶 is always high


• 𝑃𝑃2 is the point of intersection of 𝑈𝑈𝑍𝑍 −C3 𝑎𝑎𝑎𝑎𝑎𝑎 𝑈𝑈𝑍𝑍 − 𝐶𝐶𝐶




19

Conclusions

20

• The voltage distance curve provides a good visual depiction of thesimulation results.

• For most cases, the overvoltage increases when the distance fromthe lightning stroke location to the line entrance of the substationdecreases. Critical points are typically close to the line entrance ofthe substation.

• Installing surge arresters either on the entrance of the substation orat the terminal of the transformer are sufficient for lightingprotection

• Installing surge arrester only at the terminal of the transformer in the SRP 500-230kV substation is proved to be both adequate and efficient with respect to the lightning performance.

Conclusions

21

Qianxue [email protected]

surge arrester placement for substation lightning protection · surge arrester s are only mounted...

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