Variable Frequency Series Resonance Test Device
About the product
The device is mainly needle 10 kv, 35 kV cable, electric generators, as well as 110 kV and below for all the main electrical equipment, such as transformers and bus switch ac withstand voltage test of the design and manufacture. The reactor is designed in more than one way, which not only can meet the test condition requirements for equipment with high voltage and low current, but also can meet requirements for low-voltage alternating-current withstand voltage test of 10kV cable. Possessing a wider application scope, it is the ideal withstand voltage equipment for prefecture-level, municipal-level, and county-level high-voltage test departments as well as power installation and repair & testing engineering units.
This unit mainly consists of a variable-frequency power supply, an exciting transformer, a reactor, and a capacitive voltage divider.
- Advantages for series resonance’s application in electric systems:
- The power capacity needed is reduced greatly. The series resonance power supply is used for generating high voltage and high current by making use of resonant reactor and capacitor resonance of the test object; the power supply only needs to provide for parts with active consumption in the whole system; therefore, the power needed for testing is only 1/Qof test capacity.
- The weight and volume of equipment are reduced greatly. It not only leaves out the cumbersome high-power pressure-regulating device and common high-power power frequency testing transformer in the series-resonance power supply; furthermore, the resonant excitation power supply only needs 1/Qof test capacity, which is 1/10-1/30of common test unit, and reduces the system weight and volume greatly.
- The waveform of the output voltage is improved. The resonant power supply is a filtering circuit in resonant mode, which can improve the waveform distortion of the output voltage, obtain a good sinusoidal waveform, and effectively prevent the wrong breakdown of harmonics peak value to the test object.
- The large short-circuit current is prevented from burning fault point. When the insulation weakness of the test object is broken down under series resonance conditions, the circuit gets tuned off immediately, and the loop current reduces to 1/Qof normal test current rapidly. When the withstand voltage test is carried out by means of parallel resonance or testing a transformer, the breakdown current can rise dozens of times immediately; the short-circuit current and breakdown current differ by dozens of times by comparing them. Therefore, series resonance can effectively find insulation weakness; meanwhile, there is not any worry for large short-circuit current burning the fault point.
- There is no restoring overvoltage. As the resonance condition will be lost when the test object is broken down, the high voltage will disappear immediately; the electric arc will burn out instantly; the restoring process of this voltage is a long intermittent oscillating process with energy accumulation, and power supply is easily cut off before reaching flashover voltage; furthermore, there is no restoring overvoltage.
- Main functions and technical features of variable-frequency resonance unit of our company:
- The unit possesses overvoltage, overcurrent, zero start, system detuning (flashover), and other protective functions. The protective values of overvoltage and overcurrent can be adjusted as per customers’ requirements. The protective function of flashover also can remember voltage value of flashover when there is a flashover of the test object, which can be used for test analysis.
- The weight of a single piece of the whole unit is very light, with no more than 40kg, which can be convenient for field service.
- There are three working modes for this unit, which are convenient for users to flexibly select according to field conditions and improve the test speed. The three working modes are fully automatic mode, manual mode, and the mode with automatic tuning and manual boosting.
- It can save data with a data number figure, which is convenient for users to identify and search.
- The frequency starting point can be set casually within the specified scope, and the frequency sweeping direction can be selected upward or downward during the automatic frequency sweeping process of the unit. Meanwhile, the large LCD screen can show the scanning curve, which is convenient for users to intuitively understand whether they can find the resonance point or not.
- It adopts DSP platform technology, which is convenient to add or delete functions and upgrade according to customers’requirements, and enables the man-machine interface to become more humanized.
BPXZ-270kVA/270kV Main technical parameters for test unit of variable-frequency series resonance
(I) BPXZ refers to the code of the manufacturing factory.
(II) Technical index for BPXZ-270kVA/270kV
test unit of variable-frequency series resonance
- Rated voltage:
45kV—meeting the alternating current withstand voltage test for 10kV cable；
135kV—meeting the alternating current withstand voltage test for 35kV system and 35kV cable；
270kV—meeting the alternating current withstand voltage test for 110kV system;
- Waveform distortion rate of output voltage should be less than 1.0％.
- The permissible continuous working time is to work for 5 minutes at a time under rated conditions.
- Quality factor of the unit itself: Q>50
- Quality factor under full load in test of fire power generator: Q>10(relating to load)
- Quality factor under full load in cable test: Q>30(relating to load)
- Quality factor under full load in test of main transformer: Q>30(relating to load)
- GIS, the quality factor under full load in switch test and other tests: Q>50(relating to load)
- Input power supply: single phase of 380V
- Frequency adjustment range: 20Hz～300Hz
- Accuracy of system measurement: 1.5％
- The unit possesses protective functions, such as overvoltage, overcurrent, and zero start.
(III) Standards followed by equipment
Standard for Hand-Over Test of Electric Equipment and Electric Equipment Installation Engineering GB50150-2006
High-voltage Resonance Test Unit DL/T 849.6—2004
Reactor GB10229.88
Preventive Test Code for Electric Power Equipment DL/T596-1996
Coupling Capacitors and Capacitor Divider IEC358 (1990)
(IV) Description for main configuration and technical data of equipment:
- One set of variable-frequency power supply:
Rated power:15kVA；
Input voltage: single phrase of 220V or three phase of 380V±10% and 45～65Hz
Output voltage: 0～400V adjustable
Output voltage frequency: 30～300Hz
0.1Hz adjustable stepping
Instability degree of frequency ≤0.02%
Output current: 0～37.5A
- High-voltage resonane reactor (6 sets in all):：45kV/1A
Rated working voltage：45kV
Rated working current：1A
Rated inductance value：100H
Continuous working time：60min
Temperature rise should be less than 60℃.
Working frequency: 30~300Hz
- One set of exciting transformer：
Rated capacity：15kVA
Rated capacity：200V/400V
Output voltage：1.5/3/5/15kV
- One set of capacitive divider: 270kV, pure capacitance
Its own capacitance：500pF
Working frequency: 30～300Hz
Uncertainty: 1.5%
Rated voltage:135kV/1000pF，270kV/500pF
- 1 set of test line and accessories:
1) 1 set of internal connecting line
2) 2 reactor insulation base
3) 2 equal pressure ball
4) 1 set of voltage divider stent
5) 1 piece of operation instruction
6) 1 piece of test report
