GDTF-7200kVA/400kV Variable Frequency AC Series Resonant Test System

• After-sales Service: Yes
• Warranty: 1 year
• Rated output voltage: 0~400kV
• Output voltage waveform: sine wave
• waveform distortion rate: <1.0%
• Rated capacity: 7200kVA
• Model NO.: GDTF-7200kVA/400kV
• Working Frequency: 30-300Hz
• Quality factor: 30~90
• Transport Package: Standard Plywood Case
• Specification: ISO
• Trademark: HV HIPOT
• Origin: Wuhan, China

Product Description

GDTF-7200kVA/400kV Variable Frequency AC Series Resonant Test System

I. Test Object and Requirement

The system is specially designed for AC withstand voltage test for cable, with below specifications and requirements.

Test Object	Test Length	Capacitance	Test Frequency	Test Voltage	Test Time
1400mm^2, 110kV Power cables	3km	≤0.777uF	30-300Hz	≤128kV	60mins
2500mm^2, 220kV Power cables	3km	≤0.8uF	30-300Hz	≤180kV	60mins
220kV GIS			30-300Hz	≤380kV	1min
110kV GIS			30-300Hz	≤235kV	1min

II. Working Environment
 

1. Environmental temperature: -15ºC to 40ºC
2. Related humidity: ≤ 90% RH
3. Altitude: ≤3500m

III. Technical Data
 

1. Rated output voltage: 0~400kV
2. Output voltage waveform: sine wave, waveform distortion rate: <1.0%
3. Max. Current for undertest object: 18A (400kV), 36A (200kV)
4. Rated capacity: 7200kVA
5. Working Frequency: 30-300Hz
6. Working time: constant working of 60mins under rated load.
7. Quality factor: 30~90
8. Input power supply: Three phase 380V±5%, 50Hz
9. Protective function: Over-current, over-voltage and flashover protections for test object.

1. Environmental temperature: -15ºC to 40ºC
2. Related humidity: ≤ 90% RH, non-condensation
3. Altitude: ≤3500m
4. Noise: ≤50dB

IV. System Features
 

1. Completely independently develop, design and produce all the components of this set of equipment including: variable frequency power supply, excitation transformer, cast-type high-voltage reactor and high-precision capacitive voltage divider .
2. Equipped with manual/automatic mode, large screen display, test parameter setting, and automatic timing and operation prompt functions.
3. Possess multiple protection functions, such as: overvoltage, overcurrent protection, discharge protection, detuning protection, etc.

V. Applied standard

GB50150-2016   Electric equipment installation engineering-standard for hand-over test of electric equipment
DL/T849.6-2004   General technical specification of test instruments used for power Part 6: high voltage resonate test system
JB/T9641-1999    Test type transformer
GB10229      Reactor
GB/T.311-1997   Insulation co-ordination for high voltage transmission and distribution equipment
DL/T846-2004   General technical specifications for high voltage equipments
GB4793-1984    Safety requirements for electronic measuring apparatus
GB2900         Electrotechnical terminology
GB4208         Degrees of protection provided by enclosure (IP code)
GB191          Packaging-Pictorial marking for handling of goods
GB/T16927-1997   High-voltage test techniques


VI. Capacity Determination of the equipment

For example,

AC withstand voltage test for 2500mm², 220kV power cables, 3km, capacitance ≤0.8μF, test frequency 30-300Hz, test voltage U ≤ 180kV.

We choose Frequency 35Hz
Test current I = 2πfCU_test =2π×35×0.8×10^-6×180×10³=31.7A
Then L=1/ω²C=26H

Then use 2pcs reactors, 2pcs reactor in parallel, each reactor is 3600kVA/200kV/18A/52H, the total capacity is 7200kVA.

Verification:

1400mm², 110kV cable 3km AC withstand voltage test, capacitance ≤0.777uF, test frequency 30-300Hz, test voltage ≤128kV. 
Use two reactors are connected in parallel, then L=52/2=26H, then:
Test frequency: f=1/2π√LC=1/(2×3.14×√26×0.777×10^-6)=35.4Hz
Test current: I=2πfCU _test = 2π×35.4×0.777×10^-6×128×10³=22.1A.


Conclusion: The device capacity is set to 7200kVA/400kV, divided into two reactors, and the single reactor is 3600kVA/200kV/18A/52H. The combination of reactors can meet the test requirements of the tested product.

The reactors used in series or parallel meet the testing requirements.
 

COMBINATION Test object		REACTOR 3600kVA/200kV 2pcs	EXCITATION TRANSFROMER OUTPUT SELECTION
110kV/1400mm^2power cable(test voltage≤128kV, test time 60min)	1500m and below	1pcs reactor	4kV
	1500m~3000m	2pcs reactor in parallel	4kV
220kV/2500mm^2power cable(test voltage ≤180kV, test time 60min)	1500m and below	1pcs reactor	4kV
	1500m~3000m	2pcs reactor in parallel	7.5kV
110kV GIS(test voltage ≤235kV, test time 1min)		2pcs reactor in series	20kV
220kV GIS(test voltage ≤380kV, test time 1min)		2pcs reactor in series	20kV