3KVA/150KV High Voltage Test Transformer
Recommended by Darui Electric
Technical Requirements:
1. Environmental requirements for the test transformer:
1.1 Input voltage: AC 220V or 380V, 50Hz;
1.2 Ambient temperature: -40℃ to 40℃;
1.3 Relative humidity: ≤85% (at ambient temperature of 25℃);
1.4 Environment free from chemical gases and vapors;
1.5 Atmosphere without explosive hazardous gases;
1.6 Places not subject to rainwater ingress.
Note: 1. Our factory's TQSB series test transformers can achieve AC 300kV with a capacity of 300kVA as a single unit;
2. If required by users, our TQSB series test transformers can be equipped with a 200V cascade tap, allowing two or three units to be cascaded to produce high voltages of AC 100kV, 150kV, 200kV, or 300kV. Additionally, according to user needs, a 5-15kV intermediate voltage tap can be extracted from the high-voltage winding for AC withstand voltage testing of high-voltage motors;
3. The "DC High Voltage Output" column in the table refers to the DC high voltage output value of the AC/DC dual-purpose test transformer;
4. Our factory can also customize various special specifications of test transformers according to user requirements.
Operation Steps:
1. Connect the leads according to the wiring schematic diagram, and ensure reliable grounding of the transformer and control box;
2. Before testing, check whether the connections at all parts are in good contact, and verify that the voltage regulator of the control box is adjusted to the "zero" position;
3. Connect the power supply, the green indicator light will illuminate. Press the start button, the red indicator light will illuminate, indicating that the transformer is energized and ready for voltage increase;
4. Rotate the voltage regulator handle clockwise at a uniform speed to increase the voltage, while closely monitoring the instrument readings and the condition of the test object;
5. After the test, quickly reduce the voltage to zero, press the stop button, then disconnect the power supply and remove the test leads.
Precautions:
1. When conducting high voltage tests, at least 2 or more personnel must participate, with clear division of labor and mutual communication methods. A dedicated person should supervise on-site safety and observe the test status of the test object;
2. The transformer and control box should have reliable grounding;
3. During the test, the voltage increase speed should not be too fast, and sudden full voltage application or disconnection is absolutely not allowed;
4. During voltage increase or withstand voltage testing, if any of the following abnormal conditions are found, immediately reduce the voltage, disconnect the power supply, stop the test, and investigate the cause before resuming: ① Significant fluctuation of the voltmeter pointer; ② Detection of burning odor or smoke from insulation; ③ Unusual sounds from the test object.
5. During the test, if the test object short-circuits or breaks down, the overcurrent relay in the control box will operate. At this time, return the voltage regulator to zero, disconnect the power supply, and only then can the test object be removed.
6. When conducting capacitance tests or DC high voltage leakage tests, after the test, reduce the voltage regulator to zero, disconnect the power supply, and then use a discharge rod to discharge the high-voltage terminal of the test object or capacitor to ground to avoid electric shock from residual charge in the capacitor.
Capacity Selection of Test Transformer:
The formula for determining the nominal capacity Pn of the test transformer: Pn=kVn2WCt10-9 Where: Pn - nominal capacity of the test transformer (kVA);
k - safety factor; Vn - rated output high voltage RMS value of the test transformer (kV); W - angular frequency, W=2πf, f is the frequency of the test power supply; Ct - capacitance of the test object (PF).
For different test voltages Vn, select an appropriate safety factor k. When the nominal test voltage is lower, a higher k value can be used; the following lists the safety factor k values for different test voltages Vn for reference: Vn=50～100kV k=4; Vn=150～300kV k=3; Vn≥300kV k=2; Vn≥1MV k=1.
The capacitance Ct of the equipment under test can be measured using an AC bridge. Ct varies greatly and depends on the type of equipment. Typical data are as follows:
Rod or suspension insulators: several tens of microfarads; voltage transformers: 200～500PF; graded bushings: 100～1000PF; power transformers <1000kVA: ~1000PF; power transformers >1000kVA: 1000～10000PF; high-voltage power cables and oil-impregnated paper insulation: 250～300PF/m; gas insulation: ~60PF/m; , , , , enclosed substations, SF6 gas insulation: 100～10000PF.
Product Introduction:
3KVA/50KV Lightweight High Voltage Test Transformer is a new type of high-voltage testing equipment. This series of products adopts a single-frame core-type iron core structure, with the primary winding and high-voltage winding coaxially wound on the iron core, thereby reducing leakage flux and increasing coupling between windings. The overall structure of the product is compact, with strong versatility, and is easy to use and carry. It is suitable for on-site testing of the insulation performance of various high-voltage electrical equipment in power systems and power users, and is an essential test instrument for power equipment testing and preventive maintenance.
In addition to AC power frequency withstand voltage testing, if equipped with capacitors, silicon stacks, and high-voltage DC microammeters of the same voltage level and capacity, it can be assembled into a DC high-voltage testing device to measure high-voltage DC leakage current.
Note: The above information and technical parameters are compiled and released by Yangzhou Darui Electric Co., Ltd.
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