Secondary circuit testing equipment is diverse and mainly used to ensure the accurate, reliable, and safe operation of secondary circuits in power systems. The following are some common types of equipment and their functions:
Relay Protection Tester: This is the core equipment for secondary circuit testing. It can simulate various power faults (such as overcurrent, overvoltage, differential protection, etc.) to test the operating values, return values, operating times, and logic functions of protection devices, and verify the correctness of circuit wiring.
Instrument Transformer Characteristic Testing Equipment:
CT Analyzer/Voltage-Ampere Characteristic Tester: Tests the excitation characteristics, ratio, polarity, ratio difference, and phase difference of current transformers to ensure they meet protection and measurement requirements.
PT/CT Ratio Tester: Quickly measures the ratio of voltage or current transformers.
Instrument Transformer Polarity Verifier: A specialized tool used to quickly verify the polarity of CTs or PTs.
Secondary Voltage Drop and Load Tester: Used to measure the voltage drop of the secondary circuit of voltage transformers (PTs) and the actual load of the secondary circuit of current transformers (CTs), assessing energy metering errors. Supports online measurement without power interruption.
Loop Resistance Tester: Used to measure the contact resistance of conductive circuits such as high-voltage switches and circuit breaker contacts, ensuring good equipment connections and preventing overheating faults.
Basic General Instruments:
Multimeter:Measures voltage, current, and resistance; used for circuit continuity checks.
Clamp-on Ammeter: Non-contact current measurement, suitable for circuits in operation.
Insulation Resistance Tester (Megohmmeter): Detects insulation resistance between conductors or to ground, preventing short circuits.
Ground Resistance Tester: Measures the resistance of grounding devices, ensuring grounding safety.
Dedicated Equipment for Digital Substations:
Network Message Analyzer: Used in IEC 61850 digital substations to analyze SV, GOOSE, MMS, and other communication messages to verify the correctness of virtual loops.
