Electrical Transformer Calibration Instrument

1 Summary

Electronic current transformers are crucial foundational equipment for digital substation construction. Currently, electronic current transformers have been applied in pilot projects of digital substations, demonstrating unique advantages over traditional transformers. However, the fundamental difference between electronic current transformers and traditional transformers also introduces new practical issues in equipment calibration. Currently, in substation environments, traditional transformers only provide analog current or voltage signals.A/DTransformation is completed by subsequent secondary equipment such as electronic power meters and protective devices, but in a digital substation, all ofA/DTransformation occurs within the electronic transformer. Due to the use of the electronic transformer,A/DShifting the signal transformation from secondary to primary equipment, the characteristics of this new transformation process have garnered significant attention for the long-term operational performance of electronic current transformers. Our company's electronic current transformer online calibration instrument was specifically developed to observe and understand the long-term operational performance of electronic current transformers. It provides a means for uninterrupted, real-time monitoring of electronic current transformers through online calibration, transforming the traditional periodic maintenance approach into condition-based maintenance, thereby detecting potential equipment faults, preventing early equipment failure, and enhancing operational efficiency.

Additionally, this model of electronic transformer can also be used by manufacturers of electronic transformers for production testing of measurement errors, as well as by power metering departments for calibration.

In accordance with the national standardsG/T 20847.7Electrical Voltage TransformersG/T 20847.8Regulations for Electronic Current Transformers(ECT/EVT)There are two types of outputs: analog and digital. This product conforms to the national standards.20847.7/8Electrical Transformer StandardsIEC61850Communication standards based on virtual instruments enable the verification, recording of ratio and phase difference quantities for electronic current transformers with analog and digital outputs. They can also be applied to the verification of traditional current and voltage transformers, as well as offline verification of electronic current transformers. These standards provide a portable electronic current transformer verification device for power test, measurement, and construction units.

2. System Composition

The verification system is capable of calibrating current transformers as well as serving as a voltage transformer calibration tool. The block diagram of the verification system is as shown.1The system is divided into the Current Standard Channel, Voltage Standard Channel, Current Measurement Channel, Voltage Measurement Channel, and Calibration Instrument Data Processing Platform. The Current Standard Channel consists of the sensor part, collector, transmission module, and power management module. The Current Measurement Channel is composed of the calibrated transformer, signal converter, and transmission module. Without interrupting power supply, the sensor part converts the current on the transmission line into a voltage signal. The calibration instrument retrieves the electrical parameters of the standard current sensor and the calibrated current sensor via the collector, uploads these parameters to the computer in a standardized format. The computer data processing platform compares the two signals at the same time, calculates the error of the calibrated current sensor, displays, and records the measurement results. The Voltage Standard Channel is composed of the sensor part, collector, transmission module, and power management module. The Voltage Measurement Channel is made up of the calibrated transformer, signal converter, and transmission module. The working principle is the same as the current calibration system.

3Features

● In complianceG/T 20847.7 /8、IEC61850-9-1Standard

●Powerful and versatileG/T 20847.7 /8The verification of analog output interfaces and digital output interfaces for electronic current and voltage transformers is also applicable to the verification of traditional current and voltage transformers.

● Designed based on virtual instruments, featuring simple operation, flexible configuration, and stable system.

● High accuracy and reliability. Achieves accuracy level of0.05Level, featuringSLevel verification feature, available for0.2SLevel Electronic Current Transformer0.2Comparison and calibration of grade electronic voltage transformers.

Patented technology specially designed high-accuracy hollow-core coils enable online calibration of electronic current transformers.

The high-precision interpolation method is employed for synchronization, ensuring that the data collected from the calibrated transformer and the standard transformer are strictly synchronized in terms of timing, significantly enhancing reliability and practicality.

4Feature of the Product

● Flexible configuration, capable of customizing traditional current transformer verifications to meet different requirements/Traditional Voltage Transformer Calibration/Electrical Current Transformer Calibration/Electrical Voltage Transformer Calibration

● Calculate the current of the calibrated transformer and the standard transformer/Voltage Ratio and Phase Difference of Effective Values

● Display current conductor current, voltage, frequency, and related information for comprehensive assessment of the calibrated parameters.

● Displays the real-time waveform of the calibrated transformer output, along with relevant settings, and automatically saves verification data to generate reports.

● Flexibly configure test parameters, including test scope, number of tests, and sample point counts, among other related information.