GDYT Series PD Free Induced Voltage Test Set/System
General introduction
This test set is mainly used for offline partial discharge test for power transformers, motors and generators, and the leakage current does not exceed 500mA.
The PD test of the transformer is made by single-phase induction way;PD test of motors and generators is done by applying withstand voltage way(output 60hz high voltage, test voltage does not exceed 35kv, motor or generator's capacitance to ground does not exceed 0.038uF (equivalent to leakage does not exceed 500mA).
Use Conditions
Environmental temperature: -10ºC~+45ºC
Maximum daily temperature difference: <25K
Relative air humidity: ≤90%
Solar radiation intensity: 0.1W/cm²
Altitude: ≤1000m
Use location: outdoor/indoor
There is no danger of fire and explosion.
There is no gas that corrodes metals and insulation.
There is a reliable grounding point.
The installation place is flat.
Technical Specifications
Equipment model and name: 20kWPD Free Induced Voltage Test Set
Input working power: three-phase 380V±10%, 50Hz
Rated output power: 20kW
Rated output voltage: single phase 0~350V
Output voltage waveform: standard sine wave, waveform distortion rate ≤1.0%
Rated output frequency: 30~300Hz
Frequency resolution: 0.1Hz
Partial discharge: ≤10pC
Allowable running time: 15min allowed running time under rated capacity
Noise level: ≤65dB
Protection function
1) Input voltage protection: When the input power is under-voltage, unbalanced or lack of phase, the corresponding protection circuit in the control box will act to cut off the high-voltage output, and an alarm will be displayed on the screen. 2) Overvoltage protection: It can be set arbitrarily. When the output voltage value of the complete set of equipment reaches the protection setting value, the output will be automatically cut off and an alarm will be displayed on the screen. 3) Short circuit (over current) protection: When the output of the frequency conversion cabinet is short-circuited or the output current reaches the protection setting value, the output can be automatically cut off and an alarm will be displayed on the screen. 4) Breakdown flashover protection: When a discharge occurs on the high-voltage side or a flashover to the ground occurs, the output can be automatically cut off. 5) Zero protection: The boost must be zero, otherwise the output will not start. 6) Power failure protection: When the input power is suddenly cut off, the system uses the remaining power in the circuit to shut down the output signal in time to ensure the safe shutdown of the system. 7) Over-temperature protection: The air temperature at the entrance and exit is displayed on the screen in real time, and the data is processed by the single-chip microcomputer according to the difference of the ambient temperature. If the frequency conversion cabinet is over-temperature, an alarm message will be issued. 8) Cooling fan linkage protection: When the fan cannot run due to a fault, the variable frequency power supply cannot start or automatically cut off the output. At the same time, it has the function of automatically identifying the phase sequence of the fan power supply, without changing the phase. 9) Output voltage limit function protection: When setting the high voltage, in the test, when the voltage is raised by mistake or an abnormal situation occurs, it is ensured that the output voltage will not exceed the set high voltage. 10) Phase loss protection: When the input power is missing phase and cannot work normally, the screen will display phase loss and shut down the system at the same time. 11) Overload protection: When the output current exceeds the set current, the control box automatically turns off the output of the variable frequency power supply, and there is a corresponding prompt at this time.
Technical specifications and performance parameters of main components
6.1. PD free variable frequency voltage regulating power source 20kW 1 set
Insulation level: input and output terminals to ground ≥ 2kV/AC/1min
Allowable running time: Allowable running time under rated capacity ≥15min
Noise level: ≤65dB
Partial discharge capacity: ≤10pC under rated voltage and rated current
6.1.2 Performance Characteristics
The variable frequency power supply has the ability to resist electric field interference. Under strong electric field interference, the measurement accuracy and control protection meet the requirements.
It has good magnetic shielding, and the components and leads are shielded by high-permeability materials, so there is no space radiation.
Possess complete protection function Input voltage protection, overvoltage protection, short circuit (overcurrent) protection, breakdown flashover protection, zero protection, power curve protection, power failure protection, over temperature protection, cooling fan linkage protection, output Voltage limit function protection.
The variable frequency power supply adopts the principle of high-fidelity linear power amplification, and there is no high-order harmonics caused by IGBT switching circuits, ensuring complete sine wave output and extremely low electronic interference signals, ensuring extremely low partial discharge (≤10pC).
The variable frequency power supply is equipped with special leads and plugs to connect with other equipment and special grounding wire groups.
6.1.3 Intelligent screen display variable frequency power control box 1) Complete isolation mode:
The frequency conversion power supply cabinet and the frequency conversion power control box, and the high voltage divider are all connected by optical fibers, so that the control unit and the high voltage unit are completely isolated!
A variety of electromagnetic compatibility shielding measures and multiple protections are adopted inside the control box. At the moment of the flashover of the test product or the discharge of the equipment, it can ensure that the control box itself is not damaged by the discharge, and the personal safety of the operators can be reliably guaranteed.
The variable frequency power supply control and high voltage measurement are integrated, which can display high voltage pressure measurement information and variable frequency power supply working condition information, which is convenient for on-site monitoring. The specific operation control functions are as follows:
a. With start, stop and emergency opening buttons; b. It is equipped with the functions of step-up and step-down coarse and fine adjustment, and the adjustment rate can be set; c. It is equipped with coarse and fine frequency adjustment functions, and the adjustment rate can be set; d. Equipped with the function of automatically selecting the direction of the cooling fan; e. Automatic and manual test selection (automatic tuning, automatic boosting and depressing, etc.). f. With automatic and manual test modes (test voltage and test time can be set, automatic tuning, automatic boost and depressurization g. With the function of setting test time, the range of timing time is 0~99 minutes, the timing accuracy is ±0.1 second, and the sound reminder will be provided at the end of the time period.
Display content includes: output voltage, current, frequency, and output waveform;
6.2.PD free excitation transformer(Model:20kVA/35kV/300V/350V) 1 set
1) Rated capacity of low voltage winding: 20kVA 2) Rated voltage of low voltage winding: 300V/350V 3) Input current: 57.1A 4) Rated capacity of high voltage winding: 20kVA 5) The high voltage winding is double winding, 35kV 6) Rated voltage and current of high voltage winding: 35kV/571mA; 7) Rated frequency: 50Hz. 8) Running time: 15 minutes. 9) Partial discharge under rated voltage≤10pC
6.3.PD free coupling capacitor divider 1 set
1) Rated voltage: 50kV 2) Working frequency: 30~300Hz 3) Insulation level: 55kV/1min 4) Overall electric capacity: C1=300pF; 5) System measurement error: ≤±1.5% (measured at 50Hz frequency) 6) Dielectric loss: ≤0.5% 7) Divider ratio: 1000:1 8) Partial discharge under rated voltage ≤10pC.
Audited Supplier 
){kind=link}