Voltage transformers and current transformers play a vital role in power systems. Voltage transformers (VT) are mainly used for measurement and protection of equipment such as transformers, circuit breakers and distribution switches. Current transformers (CT) are mainly used for the measurement and protection of current in power systems. Next, we will introduce the role of voltage transformers and current transformers, selection and configuration.
First, the role of the voltage transformer
Voltage transformers are mainly used to measure and protect the voltage in the power system. They will reduce the voltage in the high-voltage system to a safe range for measuring instruments and protection devices. The role of the voltage transformer includes the following aspects:
Measurement of voltage: Voltage transformers transform the voltage in the high-voltage system into a low-voltage signal, enabling the measuring instrument to accurately measure the voltage value, thus realizing the monitoring and analysis of the voltage in the power system.
Protection equipment: voltage transformers are usually used in conjunction with protection devices to monitor the voltage in the power system exceeds or falls below the set threshold, cut off the power supply in a timely manner in order to protect the safety of equipment and personnel.
Regulation of power systems: Voltage transformers can be used to regulate and stabilize power systems. Through the monitoring and control of the voltage, you can keep the voltage in the power system within the rated range, improve the stability and reliability of the system.
Second, the role of the current transformer
Current transformers are mainly used to measure and protect the current in the power system. They will reduce the current in the high current system to a safe and measurable range for measuring instruments and protection devices. The main roles of current transformers include the following:
Measurement of current: Current transformers transform the current in a high-current system into a low-current signal, enabling the measuring instrument to accurately measure the current value, thus realizing the monitoring and analysis of the current in the power system.
Protection equipment: current transformers are usually used in conjunction with protection devices to monitor the current in the power system over or below the set threshold, cut off the power supply in a timely manner in order to protect the safety of equipment and personnel.
Realization of power measurement: current transformers are used in power distribution systems for power measurement, through the measurement of current size to determine the amount of power consumption, to provide accurate data for energy management and costing.
Third, the selection and configuration of current transformers
Selection and configuration of suitable current transformers for the normal operation and protection of the power system is very important. The following are several key factors to consider when selecting and configuring current transformers:
Rated current range: The rated current range of the current transformer should match the actual current level. If the rated current range of the selected current transformer is too small, it may not be able to accurately measure high currents, affecting the monitoring and protection effect of the power system; if the rated current range is too large, it may generate errors, affecting the accuracy of power metering.
Accuracy requirements: different application scenarios have different accuracy requirements for current transformers. For the measurement and metering requirements of the scene, should choose a higher accuracy of the current transformer. For some protection devices used in the scene, you can choose a relatively low precision current transformer.
Load capacity: the current transformer should have sufficient load capacity to ensure that the high current transient impact or fault conditions can work properly. Load capacity is usually measured in terms of short-time overload capacity and short-circuit capacity.
Matching with measurement and protection devices: Current transformers and measurement and protection devices should be well matched to each other, including the correct nominal ratio, phase difference, frequency response, etc. This will ensure that the measurement and protection devices are able to operate properly. This will ensure that the measurement and protection devices can accurately obtain the current signal and process it accordingly.
Installation and wiring: the installation and wiring of current transformers also need to be considered. Commonly used installation methods include core-piercing type, split type and switchgear type. For different application scenarios, it is necessary to choose the appropriate installation and wiring methods.
Protection level and environmental adaptability: current transformers usually need to work in harsh environmental conditions, so they need to have adequate protection level and good environmental adaptability to ensure their reliability and long life.
In short, voltage transformers and current transformers play a key role as important measurement and protection devices in the power system. Correct selection and configuration of suitable voltage transformers and current transformers can ensure the safe operation and effective management of power systems.
