In the field of maintenance and factory testing of high-voltage electrical equipment, ensuring the insulation performance of the equipment is of utmost importance. The is such a powerful tool that can deeply “check” the insulation of equipment. It is not as simple as surface work, but rather verifies whether the equipment can “withstand” harsh conditions through clever physical principles.
What is series resonance test?
Simply put, the series resonance test is a principle that utilizes an inductor (L) and a capacitor (C) to resonate at a specific frequency, generating an induced high voltage far exceeding the power supply voltage. Imagine adjusting the parameters of an inductor coil to resonate with the capacitance of the device being tested (i.e. the insulation part of the device is equivalent to a capacitor). At this point, the device can withstand a very high voltage, much higher than the AC voltage we input.
The ‘behind the scenes’ driving force that affects the effectiveness of the experiment
To conduct a reliable resonance test, there are several factors that need to be closely monitored:
Test frequency: This is the key to resonance. If the frequency is not correct, resonance cannot be discussed.
Power supply voltage and capacity: A sufficiently stable and output capable power supply is required to drive.
The quality of the inductor (reactor): Its parameters determine how high voltage can be generated, and durability is also crucial.
The capacitance of the tested device: This is the other half of the resonance, and the capacitance varies for different devices.
Experimental environment: Temperature, humidity, and other factors can also have subtle effects on the test results.
The indispensable ‘good helper’: equipment and technology
When conducting series resonance tests, we will use some professional equipment:
Control box: responsible for adjusting the frequency and voltage of the power supply, it is the brain of the experiment.
Incentive power supply: providing basic electricity.
Reactor: The core component used to form a resonant circuit with the tested equipment.
Voltage divider: used to accurately measure the test voltage applied to the tested equipment.
HV Hipot Electric Co., Ltd. has been deeply involved in this field for many years. Its has excellent stability and accuracy, and can well meet the needs of various scenarios such as AC voltage withstand testing of high-voltage cables.
What are the “relatives” related to the series resonance test?
It is a “physical examination project” for the insulation performance of high-voltage electrical equipment, similar to our partial discharge test, dielectric loss test, etc., but with different emphasis and methods. The AC withstand voltage test is its most common occurrence.
How can we do better?
Familiarity with the tested equipment: Understanding the type, capacity, and rated voltage of the tested equipment can help us set test parameters more accurately.
Strictly follow the procedures for operation: The experimental operation process and safety measures are the foundation for ensuring the quality of the experiment and personal safety.
Choosing appropriate equipment: Equipment provided by HV Hipot Electric Co., Ltd., with its stability and accuracy in harmonic withstand voltage testing, can lay a solid foundation for the reliability of test results.
Regular maintenance and calibration: Ensure the accuracy and reliability of the testing equipment itself.
FAQ
Q: What is the difference between series resonance test and DC withstand voltage test? A: The DC withstand voltage test mainly detects the DC breakdown voltage of insulation, while the series resonance test (AC withstand voltage) can simulate the actual operating conditions of equipment and test the insulation’s withstand ability under AC stress, which is a test closer to the operating state.
Q: Why is a high voltage required for conducting a series resonance test? A: In resonance state, the voltage across the inductor and capacitor will superimpose, producing a voltage much higher than the input of the power supply, in order to effectively expose potential defects in the insulation.
Q: My device is a xxx model cable. What size series resonant device do I need? A: The specific size of the equipment required depends on the capacitance of the tested equipment (such as cables) and the test voltage level you need. Usually, calculations need to be based on device parameters.
Q: What will happen if there is a sudden power outage during the experiment? A: If it is not due to equipment failure or safety protection action, under normal circumstances, as long as the power is disconnected according to the regulations after the test is completed. But if there is an abnormal power outage during the experiment, safety measures should be taken immediately according to the regulations.
Q: How to determine whether the series resonance test is qualified? A: It mainly depends on whether the tested equipment has not experienced insulation damage such as breakdown or flashover under the specified test voltage and for the specified test time during the test process.