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Test method of CTP-1000A transformer comprehensive tester


CTP-1000A transformer comprehensive tester is a new generation of CT and Pt testing instrument of our company. CTP-1000 series products are based on the testing principle of frequency conversion method, which can complete the comprehensive test of CT and PT on site without voltage regulator, voltage booster and current converter. The output voltage is low, and the safety of the tested equipment and test personnel can be ensured no matter whether there is wrong operation or not. The device adopts high-performance DSP and FPGA, and advanced manufacturing technology to ensure stable and reliable product performance, complete function, high degree of automation, high test efficiency and is in the leading level in China. It is a professional test instrument for transformer in power industry.
 
CTP-1000A互感器综合测试仪的试验方法
 
The following is a brief introduction to the current transformer test method:
 
Current transformer test
 
In the parameter interface, use the mouse to switch the cursor to the type column and select CT as the transformer type
 
Table 2.5 Description of CT test items

Resistance excitation transformation ratio load description wiring diagram
      Measurement of CT secondary winding resistance and excitation Figure 2.1
      Figure 2.1
      Figure 2.1
    Figure 2.1
        Figure 2.2
 
 
Test wiring
The test wiring steps are as follows:
Step 1: according to the description of CT test items described in Table 2.1, conduct wiring according to figure 2.1 or Figure 2.2 (for CT of various structures, refer to the actual wiring mode described in Appendix D).
 
Table 2.1ct test item description
Step 2: other windings of the same CT are open circuit, the primary side of CT should be grounded, and the equipment should also be grounded.
Step 3: turn on the power and prepare for parameter setting.
       
  CTP-1000A互感器综合测试仪的试验方法    


 
Parameter setting
The test parameter setting interface is shown in Figure 2.3.

 
The parameter setting steps are as follows:
Rotate the mouse to switch the cursor and select the test item to be carried out. When the cursor stays at a certain test item, the screen displays the parameter settings related to the test item; when the cursor leaves the test item, the screen displays the wiring diagram corresponding to the selected test item.
The parameters that can be set are as follows:
(1) Number: input the number of this test, which is convenient for printing, saving, management and searching.
(2) Rated secondary current: the rated current at the secondary side of current transformer, generally 1a and 5A.
(3) Grade: the level of the tested winding. For CT, there are 8 options, such as P, TPY, metering, PR, PX, TPS, TPX, TPZ.
(4) Current temperature: the winding temperature during the test. Generally, the air temperature during the test can be input.
(5) Rated frequency: optional values are: 50 Hz or 60 Hz.
(6) Maximum test current: generally, it can be set as the rated secondary current value. For TPY class CT, it can be set to 2 times of the rated secondary current value. For class P CT, if it is 5p40 and rated secondary current is 1a, then the maximum test current should be set as 5% * 40 * 1A = 2A; if it is 10p15 and rated secondary current is 5a, then the maximum test current should be set as 10% * 15 * 5A = 7.5A.
 
If you want to see the following results, you need to set the basic parameters accurately (it is recommended that you set them).
(1) Turn ratio error, ratio difference and phase difference
(2) Accurate calculation of limit electromotive force and its corresponding compound error
(3) The measured accurate limit coefficient, instrument safety factor and symmetrical short circuit current multiple are obtained
(4) Measured transient area coefficient, peak instantaneous error and secondary time constant
For different levels of CT, the parameter settings are also different, see table 2.2.
 
Table 2.2 Parameter Description
Parameter Description P TPY Metering PR PX TPS TPX TPZ
Rated primary current Used to calculate the exact actual current ratio
Rated load power factor Rated load on the rating plate with power factor of 0.8
Rated accuracy limit factor K The default value on the name plate is 10. It is used to calculate the limit electromotive force and its corresponding compound error              
Rated symmetrical short circuit current coefficient Kssc The default value on the name plate is 10. It is used to calculate the limit electromotive force and the corresponding peak instantaneous error        
Primary time constant default: 100ms          
Secondary time constant default: 300ms            
Work cycle C-t1-0 or C-t1-0-tfr-C-t2-0,
Default : C-t1-0 cycle
           
t1 First current passing time, Default: 100 ms            
ta11 Time for primary flow to maintain accurate limits, Default: 40ms                
tfr Time delay for first opening and reclosing, Default: 500ms. Select C-t1-0-tfr-C-t2-0 cycle to display            
t2 Second current passing time, default: 100. Select C-t1-0-tfr-C-t2-0  cycle to display          
ta12 Time for secondary flow to maintain accurate limits, Default: 40ms.
Select C-t1-0-tfr-C-t2-0  cycle to display.
           
Safety factor of rated instrument The default value on the name plate is 10. It is used to calculate the limit electromotive force and its corresponding compound error              
Rated calculation coefficient                
Rated inflection point potential Ek                
le corresponding to EK                
Area coefficient                
Rated Ual Rated equivalent secondary limiting voltage              
lal corresponding to UAL                
Step 5: select the start button on the right to test.
Note: when the name plate of transformer is lost, please input 0 for primary current and secondary load and the instrument will judge automatically according to national standard and test results.