The test device is used for conducting no-load tests, load tests, induced voltage tests on power transformers with a voltage of 52kV or less, as well as conducting partial discharge tests, temperature rise tests, and related calculations, conversions, control measurements in coordination with other equipment, all in accordance with relevant national standards.
Technical feature
1) The industrial control computer for the test bench runs on the Windows operating system. The test software is in a fully Chinese language environment. During the test process, simply clicking the corresponding buttons with the mouse will automatically complete the entire test item. All test data is displayed on the screen in real time. During the test, the display is automatically locked for a moment to facilitate the operators' reading of the values.
2) The measurement is carried out using our power analyzer. The data from the power analyzer is sent to the computer via the network port and participates in the control, protection, measurement, and calculation of the entire system. The no-load loss and load loss values can be immediately converted on the computer.
3) The voltage transformer and current transformer adopt an oil-immersed insulation bucket structure and are adjusted electrically. They can be operated directly on the computer, and the results are displayed on the computer.
4) The test software includes password protection. It can be set so that the operators must enter a number and password before they can start working, and the test data is recorded in the hard disk database. At the same time, all test data can be saved in Access database format to form historical archives, which is convenient for future query and analysis.
5) The industrial control computer for the test bench is equipped with a CD burner and a USB universal serial bus interface. Users can back up or transfer the test data by burning a CD or connecting an external removable storage device.
6) The control cabinet and the computer communicate via optical fiber for signal transmission. The computer transmits the operation instructions to the control cabinet, which converts them into the action signals of the contactors. At the same time, the action information of the contactors and the measurement reference parameters are uploaded to the computer.
7) A liquid crystal display panel is installed on the control cabinet body to display the action information of all contactors and the measurement reference parameters. It can operate all the contactors' actions without the control of the computer.
8) To prevent abnormal situations during the test, the system has set multiple protection measures to ensure the safety of equipment and personnel in abnormal situations.
9) In the automatic test bench, in addition to automatic measurement, manual operation (clicking buttons in the computer program) can also be used according to the test requirements to select the current transformer and voltage transformer positions, and operate all switch actions arbitrarily.
10) Mechanical emergency stop buttons are provided on the test bench and the control cabinet to immediately disconnect the test circuit in case of emergency, ensuring the safety of personnel, equipment, and the tested object.
Control Part
The control of the transformer test bench adopts a programmable controller (PLC) as the lower-level computer, and an industrial control computer as the upper-level computer. The normal operation is commanded by the computer to the PLC. All locking, interlocking, and protection are completed in the program of the programmable controller. When the protection is activated, the PLC acts quickly and then feeds back the action information to the computer. The communication between the computer and the PLC uses optical fiber transmission and the Ethernet protocol, which can ensure fast transmission, ensure potential isolation, and also ensure the safety of the computer. The communication between the PLC and the sensors uses RS/485.
1) controlling item
Control of opening and closing of the output circuit breaker of the frequency conversion power supply.
Control of opening and closing of the output circuit breaker of the frequency conversion power supply.
Control of opening and closing of the input and output circuit breakers of the voltage regulator,
Control of opening and closing of the primary side circuit breaker of the intermediate transformer.
Control of opening and closing of the isolation knife switch for high voltage output.
Control of switching gears for the no-load automatic switching of the intermediate transformer's primary side.
Control of opening and closing of the pneumatic switch of the capacitor tower.
Control of gear shifting of the voltage transformer.
Control of gear shifting of the current transformer.
2) Switch status display
Display of all circuit breaker switch status
Display of all isolation switch status (Isolation switches need to have position contacts)
Display of relay protection action status
Display of the position of the intermediate transformer tap changer (Electrically operated no-load tap changer, with position contacts)
Display of the open and close positions of the high-voltage output pneumatic isolation switch.
Display of the position of the reactor tap changer (Electrically operated no-load tap changer, with position contacts)
Display of the open and close status of the capacitor tower pneumatic switch
Display of the voltage transformer gear position
Display of the current transformer gear position
3) Protection
The system configuration is as follows for protection:
Intermediate transformer input overcurrent protection
Frequency converter power supply output overvoltage protection
Frequency converter power supply output overcurrent protection
Frequency converter power supply output overcurrent protection
Frequency converter power supply output overvoltage protection
Voltage regulator input current protection
Voltage regulator output voltage and current protection
Reactance overcurrent protection
Voltage unbalance protection of the tested item
Overcompensation of capacitors (in capacitive state)
Undercompensation of capacitors (insufficient compensation capacity)
Current imbalance of capacitors (including fuse blowout)
Low gas pressure of compressed gas (a gas pressure sensor must be equipped)
Parameter Measurement
The parameter measurements are carried out by digital sensors. The measured parameters are:
Intermediate frequency generator UA, UB, UC, IA, IB, IC, F, C, excitation U, I
Power frequency generator UA, UB, UC, IA, IB, IC, F, C, excitation U, I
Voltage regulator output UA, UB, UC, IA, IB, IC
Intermediate transformer input UA, UB, UC, IA, IB, IC
Capacitors CIA, CIB, CIC
Inductors LIA, LIB, LIC
Generator temperature, bearing temperature (the generator has a temperature sensor).
Oil station pressure, temperature. (The oil station has a temperature sensor and a pressure sensor)
Measurement accuracy ±0.5%
Refresh speed 400mS
Interface RS/485