Testing for power distribution equipment encompasses the following core items:
Insulation Performance Testing: including dielectric loss angle testing, insulation resistance measurement, and partial discharge detection.
Conductive Circuit Testing: contact resistance testing, temperature rise testing, and current-carrying capacity assessment.
Mechanical Characteristics Testing: circuit breaker opening/closing times, velocity characteristics, and mechanical vibration analysis.
Protection Function Verification: calibration of settings and operational characteristics testing for protective devices such as overcurrent, instantaneous trip, and differential protection relays.
Environmental Adaptability Testing: including assessments of moisture resistance, dust resistance, and corrosion resistance.
The scope of testing covers major power distribution equipment such as high-voltage switchgear, ring main units (RMUs), distribution transformers, cable branch boxes, capacitor banks, and various protective and control devices.
Modern testing of power distribution equipment requires a specialized suite of instrumentation:
High-Voltage Testing Equipment: including 10kV/50kV power-frequency withstand voltage testers, 2500V/5000V insulation resistance testers, and partial discharge detection systems.
Loop Resistance Testers: requiring micro-ohmmeters with a minimum resolution of 1μΩ.
Relay Protection Testers: intelligent testing units featuring six-phase current output capabilities.
Infrared Thermal Imagers: with a temperature measurement range of -20°C to 1500°C and a thermal sensitivity superior to 0.05°C.
Mechanical Characteristics Analyzers: equipped with displacement sensors and high-speed data acquisition modules.
SF6 Gas Detection Equipment: including purity analyzers and decomposition product detection devices. Additionally, auxiliary equipment such as ground resistance testers and ultrasonic detectors is required.
