AC Resonance Test System/Series Resonance Device - Test Precautions? The following are the test precautions for a series resonant device:

I. Precise Preparation Before the Test

1. Parameter Matching Calculation: Accurately estimate or measure the capacitance of the test sample, calculate the resonant frequency accordingly, and rationally configure the reactor combination and taps to ensure that the system resonant point falls within the device's operating frequency range. This is a prerequisite for a successful test.

2. Comprehensive Inspection and Grounding: Check that the excitation transformer, reactors, voltage dividers, and other components are in good condition, and that the connecting cables are undamaged. All component casings and the common grounding terminal must be reliably grounded at one point, and the grounding wire cross-sectional area must be sufficiently large.

3. Ensure Safe Distance: The high-voltage connection leads should be as short as possible, and ensure sufficient safe distance from surrounding grounded bodies (such as equipment casings, walls) to prevent flashover..

II. Precise Control of the Test Process

1. Finding the Resonant Point: Under low excitation voltage (usually less than 1/3 of the test voltage), slowly adjust the frequency and closely observe the changes in output voltage and current. When the output voltage shows a peak with frequency change, and the loop current is at its maximum, this is the resonant point.

2. Smooth Voltage Increase and Monitoring: After finding the resonant point, maintain a constant frequency and smoothly increase the excitation voltage. Simultaneously, closely monitor key parameters such as the high-voltage side voltage, loop current, and voltage divider signal.

3. Utilizing Characteristics and Handling Anomalies: At resonance, the test sample voltage is Q times the excitation voltage, and the loop is purely resistive. If flashover or breakdown occurs in the test sample, the resonance condition is disrupted, and the loop current will automatically decrease, providing current-limiting protection. However, it is still necessary to immediately and quickly reduce the voltage and disconnect the power supply.

III. Post-Test Procedures

• After the test is completed and the voltage is reduced and the power is disconnected, a dedicated discharge rod must be used to fully and thoroughly discharge the test sample (especially large-capacity test samples such as cables). Discharge should first be performed through a resistor, then directly short-circuit to ground.

Summary: The core lies in precise parameter matching and tuning, fully utilizing the resonant characteristics to achieve efficient voltage increase, and strictly following the standardized procedures for voltage increase, monitoring, and discharge to ensure the safety and effectiveness of the test. The MSXB-F-75kVA 75kV series resonant circuit is designed and manufactured primarily for AC withstand voltage testing of 10kV and 35kV cables, 10kV and 35kV main transformers, and 35kV switches.

It has a wide range of applications and is an ideal withstand voltage testing device for municipal, county, and prefecture-level high-voltage testing departments, as well as power installation and maintenance engineering units.

The circuit mainly consists of a frequency converter, excitation transformer, reactor, capacitive voltage divider, and compensation capacitors.

1. 1.5km of 10kV/300mm² cable, capacitance ≤0.563uF, test frequency 30-300Hz, test voltage 22kV, test time 5min

2. 35kV main transformer AC withstand voltage, capacitance ≤0.02uF, test frequency 45-65Hz, test voltage 68kV, test time 1min

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