DC Cable Voltage Withstand Test Standard

One,Overview:

The current management of power cable maintenance primarily relies on the items and testing cycles stipulated in the "Regulations for Handover and Preventive Testing of Electric Equipment." Insulation performance tests are conducted regularly under power-off conditions. The变频串联谐振试验 (Variable Frequency Series Resonance Test) has become widely applied domestically due to its testing conditions closely resembling the operational conditions of cables.

    Extensive testing and experience have shown that the series resonance withstand voltage test cannot quantitatively evaluate the overall insulation status of cables. Some high-voltage cables that pass the series resonance withstand voltage test still exhibit discharge breakdown phenomena in the short term. Through long-term research, testing, and practice on high-voltage cables, it is believed that partial discharge is a precursor to insulation faults in cables, and effectively detecting partial discharge is an important method to improve the level of cable condition maintenance.

Oscillating Wave Cable Partial Discharge Diagnostic and Location System (Abbreviated as)OWTSA new method (System) for power cable "condition-based maintenance". This approach involves first...XLPEApplying direct current voltage to cables enables the diagnosis and localization of partial discharges under the conditions of damped oscillatory waves formed. This method can reliably detect subtle insulation defects in cables and their junctions, as well as accurately locate them.

Our company has developed an integrated solution.10kvCable Direct Current Oscillation Wave Partial Discharge Test Device. This integrated test equipment is compact and portable, with very simple on-site wiring and wide adaptability to cable sample lengths. It allows for rapid and accurate diagnosis and location of cable partial discharges.

Section II: System Test Principle

ThroughDCThe booster source is used to increase the voltage. Upon reaching the test voltage, the electronic switch is closed, creating a damped oscillation between the resonant reactor and the test cable. Measurement and feedback control are achieved through a dedicated voltage divider. With specialized software, the localized discharge signals from the insulation weaknesses of the tested cable and its joints can be systematically displayed. Waveform data analysis allows for the measurement of discharge quantities and the precise location of the discharge points. Moreover, the software can control the repetition of the damped oscillation waveform multiple times, thereby providing a more reliable verification of the insulation defects in the tested cable.

III. System Performance and Features

1、 For new cable (pre-commissioning) handover tests and old cable (post-power outage) preventive tests.

2、 Adhere toIEC60270Standard Measurement Cable Bureau expands production capacity.

3、 Distance measurements are taken at the cable breakdown point.

4、 Measure the cable joint location and full length distance.

5The integrated main unit can automatically increase voltage according to the relevant regulations of the national grid, and the notebook system automatically collects data, making it simple and convenient.

6、 Our company has implemented a combined hardware and software anti-interference technology.,Effectively removes external interference.

7、 The software expert system concurrently displays local discharge waveforms, discharge amounts, test voltages, and other parameters, and offers real-time data saving, test report generation, and printing functionalities.