Why should CT and PT be checked and calibrated regularly?
Current Transformers (CTs) and Potential Transformers (PTs) are critical components in power systems, serving essential roles in measurement and protection. Regular inspection and calibration of CTs and PTs are vital for several reasons.
Firstly, they ensure the accurate operation of protection relays, preventing malfunctions such as false tripping or failure to trip during faults.
Secondly, for metering purposes, the accuracy of CTs and PTs directly affects the fairness of electricity billing between utilities and consumers—any deviation can lead to financial losses or disputes.
Additionally, over time, these transformers may experience issues such as core demagnetization, insulation degradation, or loose wiring connections. If left unchecked, these faults can result in inaccurate measurements or protection failures, potentially causing power outages.
National regulations and industry standards require periodic calibration of CTs and PTs to maintain system reliability and compliance. Therefore, routine inspection and precise calibration of these devices are essential for ensuring safe power system operation, safeguarding economic interests, and preventing equipment failures. This is especially important for power plants, substations, and large electricity consumers.
JYH-C CT&PT Analyzer
The JYH-C is a full-featured device designed to meet a wide range of testing requirements. It supports comprehensive testing of various types of current transformers (CTs), including TP-class CTs. Key CT test items include excitation characteristics (volt-ampere characteristics), ratio, polarity, secondary winding resistance, secondary burden, ratio error, and phase displacement. In addition, the analyzer is also suitable for testing potential transformers (PTs), covering parameters such as the excitation characteristics of the electromagnetic unit, ratio, polarity, secondary winding resistance, ratio error, and phase displacement.
Function Introduction：
1.Based on advanced frequency conversion technology, the analyzer tests the CT/PT excitation (volt-ampere) characteristic curve and the 10% error curve. It outputs a maximum of only 180 V AC voltage and 12 A RMS (36 A peak) AC current, yet is capable of testing CTs with knee points as high as 60 kV.
2.It fully meets the testing requirements for various types of current transformers (CTs), including protection-class, metering-class, and TP-class CTs, covering parameters such as excitation characteristics (volt-ampere characteristics), transformation ratio, polarity, secondary winding resistance, secondary burden, ratio error, and phase displacement. It also supports potential transformer (PT) testing, including electromagnetic unit excitation characteristics, transformation ratio, polarity, secondary winding resistance, and ratio error.
3.Compliant with international standards such as IEC 60044-1,IEC 61869-2,IEC 60044-6, ANSI C57.13the analyzer automatically selects the appropriate standard and test method based on the transformer type and accuracy class.
4.Automatically calculates key parameters such as knee-point voltage/current, 10% (or 5%) error curve, Accuracy Limit Factor (ALF), Instrument Security Factor (FS), secondary time constant (Ts), residual magnetism coefficient (Kr), saturated and unsaturated inductance, and more for both CTs and PTs.
5.Equipped with a 5.7-inch transflective graphical LCD, clearly visible under direct sunlight.
6.High-speed thermal printer for instant printing of test results and characteristic curves.
7.Automatic wiring detection with real-time error alarm prompts for incorrect connections.
8.Internal storage capacity for up to 1,000 sets of test data, with non-volatile memory to prevent data loss in the event of power failure.
9.USB support for convenient export of test results and firmware upgrades.
TECHNOLOGY SPECIFICATION:
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Type |
JYH(C) |
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|
Usage |
CT， PT |
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|
Output |
0~180Vrms，12Arms，36A（peak value） |
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|
Voltage measurement accuracy |
±0.1% |
|
|
CT Ratio |
Range |
1~40000 |
|
accuracy |
±0.05% |
|
|
PT Ratio |
Range |
1~40000 |
|
accuracy |
±0.05% |
|
|
Phase |
Range |
±2min |
|
accuracy |
0.5min |
|
|
DC resistance |
Range |
0~300Ω |
|
accuracy |
0.2%±2mΩ |
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|
Burden |
Range |
0~1000VA |
|
accuracy |
0.2%±0.02VA |
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|
Power supply |
AC220V±10%，50Hz |
|
|
Environmental Conditions |
Operating temperature : -10οC~50οC ，Humidity :≤90% |
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Weight and Dimensions |
Dimensions: 365 mm×290 mm×153mm,Weight<10kg |
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