Tettex MIDAS 2881, Руководство по эксплуатации

Страница: 158 / 164

148 Applications Guide
The following table gives an overview of recommended Test Levels for several surge arresters.
Arrester Type Arrester Unit Rating
[kV] Test Voltage
[kV]
Silicon Carbide 3.0 2.5
4.5 4.0
6.0 5.0
7.5 7.0
9.0 / 10.0 7.5
12.0 and above 10
Metal Oxide 2.7 to 3.0 2.0
4.5 to 12.0 2.5
15.0 and higher 10.0
14.8.2 Test Procedures
Surge arresters can be equipped with leakage-current detectors or discharge counters. When testing
such units the detector or counter should be short-circuited by applying a ground directly to the base
of the arrester. The short-circuit must be removed before the arrester is returned to service.
Test Procedure on a Single-Unit Arrester
Arrester assemblies consisting of single units per phase can be tested by the grounded-specimen test
method (GST). The line connected to the arrester is first de-energized and grounded, then
disconnected from the arresters.
DUT Test
Mode High
Voltage
to INPUT
A
to INPUT
HV GND
to GND
S1 GSTg A+B 1 - 2 2
Single-unit arrester measurement
Test Procedure on a Double-Unit Arrester Stack
Assemblies consisting of two units per phase are tested in the manner
outlined below. Again, the line is de-energized and grounded then
disconnected from the arrester stack.
DUT Test
Mode High
Voltage
to INPUT
A
to INPUT
HV GND
to GND
S1 UST A 2 1 3 3
S2 GST gA+B 2 1 3 3
Double unit arrester stack measurement, connection for measurement of S1.