Capacitance and Inductance Tester in power systems is often referred to as



Capacitance and Inductance Tester, in power systems, is often referred to as “Capacitance and Inductance Meter” or “Reactive Power Compensation Device Tester”. It is a specialized instrument used to measure the capacitance, inductance, dissipation factor (tanδ), and impedance of capacitors (such as shunt compensation capacitors, coupling capacitors) and reactors (such as series reactors, arc suppression coils) in power systems. With the widespread application of reactive power compensation devices (SVG/SVC) and filtering devices in the power grid, this instrument has become an essential tool for preventive tests and acceptance tests in substations. The following is an in-depth analysis combined with the technical status in 2026: 1. Core Test Objects and Functions Capacitor Testing: Test Objects: High-voltage shunt capacitors, low-voltage compensation capacitors, coupling capacitors, and voltage-dividing capacitors of CVT (capacitor voltage transformers). Key Parameters: Capacitance (C), dissipation factor (tanδ, reflecting insulation degradation), equivalent series resistance (ESR). Diagnostic Significance: Excessive deviation in capacitance (e.g., exceeding -5% to +10% of rated value) usually indicates internal element breakdown (capacitance increases) or open circuit (capacitance decreases); excessive tanδ indicates insulation moisture or aging. Reactor Testing: Test Objects: Series reactors, arc suppression coils, filter reactors, air-core reactors. Key Parameters: Inductance (L), quality factor (Q value), DC resistance (integrated in some models), impedance. Diagnostic Significance: Changes in inductance may indicate inter-turn short circuit (inductance decreases) or core loosening/displacement. Zinc Oxide Arrester Testing (some high-end models): Use the fundamental wave method to measure the total current, resistive current, and capacitive current of MOA to determine whether the arrester is damp or aging. 2. Core Working Principle High-precision variable frequency power supply + FFT analysis: The instrument generates a highly stable sinusoidal signal (frequency usually adjustable between 45Hz-65Hz, or fixed at 50Hz/60Hz) and applies it to the test object. Through high-precision A/D sampling and fast Fourier transform (FFT) algorithm, it filters out on-site power frequency interference and harmonics, and accurately extracts the amplitude and phase difference of voltage and current at the fundamental frequency. Vector calculation method: Based on the measured voltage (U), current (I), and phase difference (φ), it directly calculates: Impedance