Characteristics of Series Variable Frequency Resonant Test Device



1. It has large output capacity, high output voltage, and can arbitrarily combine reactors for AC withstand voltage tests on different test objects.

2. It has small size, light weight, and is especially convenient for field tests.

3. It has good protection functions, including overvoltage protection, overcurrent protection, time protection, flashover protection, overheating protection, module protection, etc.

4. It is extremely simple to operate and has both manual and automatic modes.

5. It uses a large screen, making test data clear at a glance, and can print test results.

6. It has no risk of overvoltage after the test object breaks down, causing relatively little damage to the test object.

7. The power supply capacity required for the test is small, only a fraction of that required for power frequency transformer tests, solving the problem of finding a power source on site.



Scope of Application of the Equipment



Standards referenced and implemented in equipment manufacturing



DL/T849.6—2004      "High Voltage Resonant Test Device"

GB 6450—1986        "Dry-type Power Transformer"

DL/T848.2—2004      "Test Transformer" 

GB/10229—1988       "Reactor" 

GB/T11920—1989      "General Technical Conditions for Control Devices"

GB/T16927.1—1997    "High Voltage Test Techniques"

IEC358—1990         "Coupling Capacitors and Capacitor Dividers"

GB311.1              "Insulation Coordination for High Voltage Transmission and Transformation Equipment"

DL/T846—2004        "General Technical Conditions for High Voltage Test Equipment"

Q/CSG10007—2004     "Regulations for Preventive Tests of Power Equipment"

GB7328—87           "Measurement of Sound Level of Transformers and Reactors"

DL474.4—1992       "AC Withstand Voltage Test"



Specific Configuration of the Equipment



1 Test requirements:

  1.1. AC withstand voltage test for 300mm2/10kv cable, length 3 km. Test time 5min, test voltage 22kv, test frequency 30～300Hz, equivalent capacitance 0.418uF/km.

2 Design of reactors:

  2.1. AC withstand voltage test for 300mm2/10kv cable, length 3 km. Test time 5min, test voltage 22kv, test frequency 30～300Hz, equivalent capacitance 1.254uF. When frequency is 35Hz.

Test current I=ωCXU test=2×3.14×35×1.254×22×10-3=6A

Corresponding reactor inductance L=1/ω2C =16.5H

3 Configuration of reactors:

  3.1. For AC withstand voltage test of 300mm2/10kv cable, length 3 km, maximum test voltage 22kv, for easy transportation, the reactor is divided into three sections, each with voltage 30KV, current 2A, and inductance 50H.

Verification:

1) AC withstand voltage test for 300mm2/10kv cable, length 3 km. Test time 5min, test voltage 22kv, test frequency 30～300Hz, equivalent capacitance 1.254uF. Use three reactors in parallel, with rated inductance 16.6H, rated voltage 30kv, rated current 6A.

Test frequency: f=1/2π√LC = 34.8Hz

Test current I=ωCXU test=2×3.14×34.8×1.254×22×10-3=6A

4 Configuration of excitation transformer:

  4.1. Since the quality factor Q value is not less than 20 under rated load, the excitation transformer is the total capacity of reactors 180KVA, divided by quality factor 20 to get 10KVA.

  4.2. The configured excitation transformer specification is YHXZB—10KVA/1.5kv/3kv.

5 Configuration of frequency conversion power supply:

  5.1. The capacity of the frequency conversion power supply is equal to or greater than that of the excitation transformer, taken as 10kvA.

  5.2. The configured frequency conversion power supply specification is YHXZB—10kvA.

6 Configuration of capacitive voltage divider:

  6.1. Since the maximum test voltage is 22kv, the capacitive voltage divider voltage is 30kv, capacitance 10000PF.

  6.2. The configured capacitive voltage divider specification is FRC—30kv/0.01uF.



Description of Each Component of the Device



1. System parameters:

 1.1. Instrument input voltage: 220v±10%   50Hz;

      Power input voltage: 380v ±10%   50Hz;

 1.2. Rated output voltage adjustment range: 0 ~30kv;

 1.3. Maximum test capacity: 180kvA;

 1.4. Resonant voltage waveform: sine wave, distortion rate: ≤0.5%;

 1.5. Output voltage instability: ≤0.5%;

 1.6. Output frequency range: 25～320Hz;

 1.7. Frequency adjustment resolution: 0.01Hz;

 1.8. Quality factor Q value: not less than 20 under rated load;

 1.9. Insulation level: 1.2 times rated voltage withstand for 1min;

 1.10. Continuous operation time under rated current: intermittent operation time 60 min;

 1.11. Voltage measurement accuracy: level 1;

 1.12. Noise: ≤45dB;

 1.13. The device is equipped with the following protection functions:

    The equipment has manual test, automatic tuning and automatic test;

    Overvoltage protection, overcurrent protection, discharge protection, power-off protection, zero-start protection.

    Test data displayed on large screen, Chinese menu, printable output, printer is embedded.



2. Frequency conversion power supply parameters:



 2.1. Rated output capacity: 10kvA;

 2.2. Instrument power: 220v±10%  50Hz;

       Power supply: 220v or 380v ±10%  50Hz;

 2.3. Rated input current: 26.3A;

 2.4. Rated output voltage: 0-340v adjustable, single phase, output voltage instability 0.05%;

 2.5. Rated output current: 29.4A;

 2.6. Frequency adjustment range: 25～320Hz;

 2.7. Continuous operation for 60min at rated capacity, maximum temperature rise ≤60K;

 2.8. Display the following parameters:

    a. Frequency, voltage, current after frequency conversion output;