Characteristics of Series Variable Frequency Resonant Test Device



1. Large output capacity, high output voltage, and reactors can be arbitrarily combined for AC withstand voltage tests on different test objects.

2. Small size, light weight, especially convenient for field tests.

3. Good protection functions, including overvoltage protection, overcurrent protection, time protection, flashover protection, overheating protection, module protection, etc.

4. Extremely simple operation, with both manual and automatic modes.

5. Large screen display makes test data clear at a glance, and test results can be printed.

6. No risk of overvoltage after test object breakdown, causing minimal 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 difficult on-site power supply.



Scope of Equipment Application



Standards referenced and implemented in equipment manufacturing



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

GB 6450—1986        "Dry-type Power Transformers"

DL/T848.2—2004      "Test Transformers" 

GB/10229—1988       "Reactors" 

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 Distribution 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 Equipment Configuration



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 Reactor design:

  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=ωCXUtest=2×3.14×35×1.254×22×10-3=6A

Corresponding reactor inductance L=1/ω2C =16.5H

3 Reactor configuration:

  3.1. AC withstand voltage test for 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. Three reactors connected in parallel, rated inductance 16.6H, rated voltage 30kv, rated current 6A.

Test frequency: f=1/2π√LC = 34.8Hz

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

4 Excitation transformer configuration:

  4.1. Since the quality factor Q value is not less than 20 under rated load, the excitation transformer is the total reactor capacity 180KVA divided by the quality factor 20, resulting in 10KVA.

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

5 Frequency conversion power supply configuration:

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

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

6 Capacitor voltage divider configuration:

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

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



Description of Device Components



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: class 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 under rated capacity, maximum temperature rise ≤60K;

 2.8. Display the following parameters:

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