Pruebas electricas a pararrayos

Surge Arresters

Silicon Carbide

Metal Oxide

Shunt Resistor Gap Valve Element

(MCOV & MOV)

Older Designs

Newer Designs
2

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Surge Arresters

Normal Condition ==> Insulator Instant of Disturbance ==> Conductor Passing of Disturbance ==> InsulatorNon-Linear Volt-Ampere Characteristic Dielectric-Loss Test - Not a Test of The Arrester’s Protective Characteristics

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Silicon Carbide
100KV 69KV 100KV 69KV

Metal Oxide

•Over design ratings it dissipates the impulse •Drops down to zero •Generates its own impulse

•Over design ratings it dissipates theimpulse •Clamps the voltage •Doesn’t drop to zero •Doesn’t generate its own impulse
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Surge Arresters

To make comparisons meaningful, arresters must be tested at the same voltage levels For recommended test voltages:
M2H Manual, page 4-118 M4K Manual, page 8-138Clean all porcelain surfaces to minimize surface leakage

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Refer to Tabulation in the Doble Test Data-Reference Book
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Surge Arresters

Single Arrester:
High Voltage Lead

CKTSW

CKT SW

A

Test Set Step-Up XFMR Guard LVL

I&W Meter

GND Lead

89 Years of Diagnostic Instrumentation and Services for the Electric Power Industry

1. Bus must be disconnected from top of unit. 2. Place HV test lead as shown. 3. If discharge counter present, place jumper from bottom of arrester to ground, bypassing the counter. 4. Connect test set ground to grounded structuresupporting arrester stack. 5. Use a GST-Ground test circuit.

HV Cable

Test Set Ground Lead

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Surge Arresters

Two Arresters:
High Voltage Lead

CKT SW

CKT SW

A

Test Set Step-Up XFMR
Guard

B

GND Lead LVL I&W Meter

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1. Place test leads as shown. Colors may be interchanged. Bus must be disconnected from top unit.

Red/Blue LV Lead
1

A 2. If discharge counter present, place High Voltage Lead jumper from bottom of B to ground, bypassing the counter. B 3. Connect test set ground to grounded structure supporting arrester stack. Test Set
GroundLead

2

3

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Surge Arresters

4. A and B must be measured one at a time as follows:
Choose This Circuit UST Measure Red GST Guard Red To Measure A B
Red/Blue LV Lead
1

5. Use the multiple test choice to speed testing 6. This example uses the Red lead.The blue lead could have been used instead, and all test circuit choices would then have the red replaced by blue.

A
High Voltage Lead
2

B
3

Test Set Ground Lead

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1

Test #1

A
2

B
3

No. Mode Energize Ground Measure 1 GST 1 2 A
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Surge Arresters

Test #2 1

A
2

B
3

No. Mode Energize Ground Measure 2 GST 2 3 B
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1

Test #1A

A
2

B
3

No. Mode Energize Ground Guard UST Measure 1A UST 2 3 ---1 A
89 Years of Diagnostic Instrumentation and...