High Voltage Gas Insulted Substation (GIS) Routine Tests According to IEEE C37.122
Dyson
04/08/2025 09:24:58
Routine tests, also commonly known as production tests, are carried out to verify that each Gas - Insulated Metal - Enclosed Switchgear (GIS) functions as per its design and the parameters established during type - testing. These tests are conducted on every GIS unit after assembly and represent a crucial quality checkpoint before the GIS is dispatched from the factory. The test parameters are derived from type - test results, meaning that, within specific tolerances, routine test outcomes must mirror the type - test data.
The subsequent sections briefly describe the Routine Tests specified in the IEEE C37.122 standard:
Dielectric Tests
Dielectric tests are conducted subsequent to mechanical routine testing. They serve to demonstrate the dielectric performance of the GIS. These tests ensure proper assembly, confirm that components are correctly manufactured from a dielectric perspective, and verify the absence of particles and other contaminants.
- Power frequency dielectric test: For routine testing, the dielectric test takes the form of a power frequency withstand voltage test. Impulse testing, such as lightning and switching impulse tests, is not usually part of routine testing. At the minimum functional SF6 pressure, the following conditions are examined: phase - to - ground, phase - to - phase (in the case of a three - phase - in - one - enclosure design), and across open switching devices. The primary criterion for a successful test is withstanding the one - minute withstand voltage level without experiencing a disruptive discharge.
- The measurement of partial discharges: This measurement is carried out to detect potential material and manufacturing defects. It is performed in conjunction with dielectric tests after mechanical routine tests. The test should be executed on all components of the gas - insulated switchgear.
Measurement of the Resistance of the Main Circuits
Typically, the voltage drop or resistance of the main circuits is measured using a 100 A DC current. The test data should fall within a 20% tolerance range when compared to the type - test data.
Tightness Tests
Devices such as SF6 piping, SF6 leakage detectors, all areas of enclosure assemblies, SF6 gauges, and SF6 density monitoring equipment are utilized to check for leaks.
Pressure Tests of Enclosures
Once the enclosures are fully machined, pressure tests are conducted. For welded aluminum and welded steel enclosures, the test pressure is set at 1.3 times the design pressure. In the case of cast enclosures, the test pressure is 2 times the design pressure. Automated test stations enable the integration of a tightness test using helium immediately after the enclosure's pressure test.
The standard test pressures are as follows:
- For welded aluminum and welded steel enclosures, it is 1.3 times the design pressure.
- For cast aluminum and composite aluminum enclosures, it is 2 times the design pressure.
The test pressure must be maintained for a minimum of 1 minute. During this test, no rupture or permanent deformation of the enclosure should occur.
Focused on the design of electrical equipment, proficient in electrical principles and relevant specifications, and skilled in using design software. From intelligent substations to various types of electrical equipment, I am adept at optimizing design solutions, integrating new technologies. With practical experience and collaborative management capabilities, I deliver outstanding electrical design achievements.
