PDIV (Partial Discharge Inception Voltage) test is an important means to evaluate the insulation status of electrical equipment. Partial discharge refers to the phenomenon of local electrical discharge occurring inside or on the surface of the electrical insulation material, which usually indicates the deterioration or defect of the insulation material. The main purpose of PDIV testing is to determine the voltage level at which partial discharge begins to occur in order to evaluate the insulation performance and reliability of the equipment.
First, the basic principle of PDIV testing
The basic principle of PDIV testing is to gradually increase the voltage applied to the device under test until a partial discharge signal is detected. The occurrence of partial discharge is usually related to factors such as defects, bubbles or impurities in the insulation material. When the voltage reaches a certain level, these defects will lead to partial discharge phenomenon.
1. The formation of partial discharge The formation of partial discharge is closely related to the strength of the electric field, the dielectric properties of the insulation material and the nature of the defect. In the process of applying voltage, the electric field strength gradually increases, when a certain critical value is reached, the defect area in the insulation material will produce ionization phenomenon, resulting in the occurrence of partial discharge.
2. Test equipment and technology PDIV testing usually uses specialized test equipment, such as partial discharge analyzers. These devices can monitor partial discharge signals in real time and record relevant data. The test equipment is usually equipped with high voltage generator, signal processing unit and data acquisition system, so as to make more accurate analysis of partial discharge.
Second, the testing process of PDIV test
The process of PDIV testing generally includes the following steps:
1. Preparations Before performing a PDIV test, make full preparations for the device to be tested. This includes cleaning the surface of the device, checking the status of the connection wire and testing the device to ensure the accuracy and safety of the test.
2. Connect the test device. Connect the PDIV test device to the test device. Ensure that the connection is strong to avoid accidental disconnection during testing. When connecting, attention should be paid to the isolation of high and low pressure areas to ensure the safety of the operator.
3. Apply voltage to start the test equipment and gradually apply voltage. Typically, the test voltage will start from zero and gradually increase in a preset step size. After increasing a certain voltage step, the device will monitor the partial discharge signal.
4. Monitoring partial discharge signal In the process of applying voltage, the test equipment will monitor the partial discharge signal in real time. When the partial discharge signal first appears, the voltage value at this time is recorded, which is the partial discharge initial voltage (PDIV).
5. Data analysis After completing the test, perform data analysis. The test results are usually based on the PDIV value and the characteristic parameters of partial discharge (such as discharge amplitude, frequency, etc.) to evaluate the state of the insulation material and the health of the equipment.
6. Result report Finally, sort out the test results and write the report. The report should include information such as test conditions, test equipment, PDIV value and analysis results, so as to facilitate subsequent decision and maintenance.
Third, the application of PDIV test
PDIV test is widely used to evaluate the insulation performance of power equipment, including transformers, generators, switchgear and so on. Through regular PDIV test, insulation defects can be found in time, equipment failures can be avoided, and the safe and stable operation of power system can be guaranteed.
1. Transformer In the maintenance of transformers, PDIV testing can help identify the aging of insulation materials and determine whether the transformer needs to be repaired or replaced.
2 generator generator as an important part of the power system, its insulation performance directly affects the stability of power generation. The PDIV test can effectively evaluate the insulation status of the generator and reduce the risk of failure.
3. Switchgear Switchgear in the power system assumes important control and protection functions, PDIV test can ensure that its insulation performance meets the operation requirements, thereby improving the reliability of power supply.
As an important insulation performance evaluation method, PDIV test plays an important role in the maintenance and management of power equipment. By understanding the basic principle and testing process of PDIV test, relevant personnel in the power industry can better apply this technology to ensure the safe and reliable operation of equipment.