CT Electric Meter Advantages
1. It use external current transformers as the measuring element of current, which can realize non-contact measurement, reduce the connection nodes of the power line during the installation of the meter, avoid the safety hazards caused by direct contact with high voltage, and improve safety and reliability.
2. It is installed with current transformers, which are easy to install. During the installation process, you only need to connect the current transformer to the circuit under test without changing the circuit. It is easy to install, easy to operate and maintain, and can save installation and maintenance costs.
3. Use external CT to measure large currents and a wide range. This can be achieved by replacing current transformers that meet the use requirements; electric energy meters with CT are basically required for currents above 100A.
4. The measurement accuracy of electric energy meters with CT is usually higher than that of ordinary electric energy meters, and can more accurately measure the operating status and power consumption of the power system.
5. The energy meter with CT has the ability to resist electromagnetic interference and lightning strikes, and can operate stably in complex environments. It has high safety performance and can ensure the stable operation of the power system and the safety of operators.
In terms of design principle, there are two different forms, one is an external CT mutual inductance electric energy meter, and the other is an external CT direct electric energy meter.
When designing, the electric energy meter has a sampling device, a current transformer or a shunt, inside, and the sampling is obtained by the externally installed current transformer.
The current signal is converted again through the internal current transformer or shunt. Common current transformer forms are 100:5, 200:5, 500:5, 1000:5, 2000:5, etc., and the calculation needs to be multiplied by the multiple of the transformation ratio.
The external CT direct electric energy meter directly inputs the current signal obtained by sampling the external current transformer into the metering chip of the electric energy meter. Commonly used current transformer forms are coil turns ratios of 2000:1, 3000:1, etc., and the measurement results are the actual power consumption data.
Open-close CT can be better applied to the field installation of electric energy meters with CT. When electric energy meters with CT are used in the field, many of them need to be installed for renovation. Electric energy meters with CT are often used for large current and thick power lines. The installation location is difficult to operate. In addition, it involves issues such as whether the installation process can be powered off for a long time. When using open-close CT, do not dismantle the connection points of the original line. Just open the open-close CT and buckle the open-close CT ring on the power line to be measured. The installation of open-close CT is very convenient, but there are several key points to note. After installation, ensure that the core cross section is fully aligned, and there should be no dust or stains on the core cross section. After closing, the connection is tightened, otherwise it will have a certain impact on the measurement accuracy of the electric energy meter with CT.