At present, when testing the error of voltage transformers based on their voltage and load characteristics, current load boxes and voltage load boxes are usually used according to the specifications on the transformer nameplate. However, what is the actual secondary load during the operation of the transformer? Is it the specified value on the nameplate of the transformer? What is the error of the transformer under actual secondary load?

To solve the above problems, it is particularly important to test the secondary load of the transformer in practice How to sample the current signal during the actual secondary load testing process is also an important issue It is neither convenient nor safe to cut off the current circuit during secondary load testing on site Our company's products use clamp type current transformers (clamp meters) to sample the line current, which is convenient for users to use

In addition, some companies use PT voltage as the working power supply for their products, which is not very safe. In this way, it is equivalent to adding load to PT/CT, and the instantaneous excitation current of the instrument transformer may cause system protection action, affecting power supply safety Our company's instruments use large capacity lithium batteries as the working power supply, which can ensure system safety and provide relatively pure power to the instruments, avoiding on-site power interference and ensuring measurement accuracy

PT wireless secondary voltage drop and load tester, wireless secondary voltage drop and load tester, secondary voltage drop and load tester, secondary voltage drop tester

1. It can achieve fully automatic measurement of three-phase three wire, three-phase four wire, and single-phase;

2. Using engineering plastic chassis to meet durability and effectively ensure the safety of testing personnel and systems;

3. The instrument has an automatic range switching function to ensure testing accuracy;

4. The combination of electronic principle circuits and DSP technology ensures good testing stability and strong anti-interference ability;

5. After the measurement is completed, various parameters related to load are automatically calculated for customer analysis and testing

6. Adopting a large screen Chinese character LCD display, all operations are prompted by Chinese character menus; The data has power-off storage and browsing functions, and can be transmitted online with a computer

7. Powered by a large capacity 7.2V11Ah lithium battery, it does not have any impact on the testing circuit and avoids system protection situations Simultaneously use without power supply on site

8. The secondary load test uses a clamp type ammeter to sample the current without disconnecting the secondary circuit It can achieve uninterrupted online measurement Automatic range switching: During the measurement process, it can be switched to different positions according to the different values of the test object, ensuring measurement accuracy and display digits

9. The production time can last up to 24 hours (maximum)

10. Comes with a lightweight charger for easy measurement, and can be connected to an external charger for measurement when the battery is low

11. The instrument has a small volume and light weight

12. Extremely wide range of secondary operating current/voltage At a working current of 50mA, it can distinguish resistance and reactance of 1m Ω, and can test the online actual load of S-class current transformers with a secondary rated current of 5A; At a working voltage of 5V, it can distinguish a conductivity of 0.001mS and store 480 sets of measurement data. After power failure, it can maintain for ten years

13. Chinese interface large screen display with RS-232 communication interface

1. Environmental conditions

--Temperature: -10 ° C~40 ° C

--Relative humidity:<85% (25 ° C) - altitude:<2500m

--External interference: no particularly strong vibrations, no particularly strong electromagnetic fields

2. Main technical indicators of the instrument during the secondary pressure drop test

1) Measurement range: Ratio difference: 0.001%~19.99% Angle difference: 0.01 '~599'

2) Resolution: Ratio difference: 0.001% Angle difference: 0.01 '

3) Basic instrument error

--DX=± (1% × X+1% × Y ± 2 characters);

--DY=± (1% × X+1% × Y ± 2 words)

Two words - quantification error of the instrument

4) Voltage meter accuracy: 0.5%

5) Scope of work

--Voltage: (50~120) V

6) Instrument indicates action value (error prompt)

--Error: Ratio difference greater than 20% or angle difference greater than 600 '

--Voltage: Voltage<2.0V

3. Main technical indicators of the instrument during PT secondary load testing

1) PT secondary load test

--Admittance measurement range: 0.1ms-50.0ms

--Accuracy of admittance measurement:

--Secondary voltage (50V-120V)

DX=± (1% × X+1% × Y ± 2 words)

DY=± (1% × X+1% × Y ± 2 words) Note: When the measured value is below 0.2mS, the test voltage should be kept above 50V, and at the same time, pay attention to keeping the through wire of the clamp meter centered At this point, the quantification error of the instrument is 5 words

2) Voltage meter head: 0.5%

4. Main technical indicators of the instrument during CT secondary load testing

--Impedance measurement range: 0.1 Ω -50.0 Ω

--Impedance measurement accuracy:

DX=± (1% × X+1% × Y ± 2 words)

DY=± (1% × X+1% × Y ± 2 words)

Two words - quantification error of the instrument

Current meter head: 1%