Principle of the HMCXZW Partial Discharge-Free Series Resonance Test Device
Partial discharge-free series resonance is essentially a high-voltage generation device based on the "series resonance principle." It primarily consists of an adjustable reactor, excitation transformer, high-voltage divider, capacitive divider, and partial discharge suppression module. Its core objective is to achieve resonance in the test circuit by adjusting electrical parameters, thereby generating high voltage on the test equipment while suppressing or eliminating partial discharge signals generated during testing.
Unlike traditional series resonant equipment, the key to the partial discharge-free design lies in controlling the "partial discharge sources." For instance, at the connection points between reactors and capacitors, the equipment employs coaxial shielding structures to reduce electric field concentration; insulation materials like epoxy resin or silicone rubber with low partial discharge characteristics are selected to reduce inherent discharge risks; even connecting cables feature dual-shielded layers to isolate external electromagnetic interference from internal signals. These combined details ensure the test circuit's partial discharge level remains below the detector's sensitivity threshold (typically ≤10 pC).
II. Workflow: Closed-Loop Control from Frequency Modulation to PD Monitoring
The operation of PD-free series resonance testing unfolds in three phases, each centered on "resonance" and "PD suppression":
1. Parameter Matching Phase: Prior to testing, technicians calculate the required reactance value (L) based on the capacitance (Cx) of the test equipment and the test voltage (U). By adjusting the reactor's inductance (or altering the number of parallel reactors), the total circuit impedance approaches pure resistance. At this point, the circuit current reaches its maximum value, and the voltage across the device equals the excitation voltage multiplied by the quality factor (Q-value), enabling effortless high-voltage output.
2. Voltage Ramp and Partial Discharge Monitoring Phase: After voltage is gradually raised to the preset value, the equipment enters steady-state operation. At this point, the partial discharge monitoring system begins real-time signal acquisition-using built-in high-sensitivity sensors (such as ultra-high-frequency sensors or ultrasonic sensors) to capture partial discharge pulses within the tested equipment. Algorithms then analyze the location, intensity, and type of partial discharge (e.g., air gap discharge, surface discharge). . Should abnormal partial discharges occur (e.g., exceeding the 100 pC threshold), the system immediately triggers an alarm and cuts off power to prevent equipment damage.
3. Voltage Reduction and Data Analysis Phase: Upon test completion, the device automatically reduces voltage to zero and generates a test report containing partial discharge levels, voltage waveforms, and frequency characteristics. Technicians can compare this data with historical records to determine whether the tested equipment's insulation status meets specifications.
