The role of the current transformer In order to ensure the safe and economic operation of the power system, the operation of the power equipment must be monitored and measured. However, the general measurement and protection device cannot directly access the high-voltage equipment, but the large current of the primary system needs to be proportional. Transform into a small current and supply it to the measuring instrument and protection device.
The function of the voltage transformer is to convert the high voltage proportionally into a standard secondary voltage of 100V or lower for protection, metering and instrumentation.
The difference between the two is that one is measuring current and the other is measuring voltage. The current transformer is connected in series in the circuit. The primary winding is less than the secondary winding, and the secondary winding cannot be opened. The voltage transformer is connected in parallel in the circuit. The primary winding has more turns than the secondary winding, and the secondary winding cannot be short-circuited.
In general, a voltage transformer is a device that converts a high voltage into a secondary standard voltage (100V) according to a certain ratio. The current transformer converts a large current or a high voltage and a large current into a secondary standard current (5A). Or 1A) equipment.
The benefits of transformation:
1. The current and voltage under high voltage cannot be directly measured. Even if there is a meter that can directly measure the current and voltage under high voltage, it is not safe. It has already led the high voltage to the electrician's eyes. It is better to manufacture the insulation, and it cannot guarantee the time. Safety.
2. When the current is too large, it is difficult to access the instrument, and the terminal of the instrument and the instrument cannot be made very large.
3. After the transformer is transformed, the secondary has become the standard current (5A or 1A) and voltage (100V), so that regardless of the secondary instrument, protection device, or energy meter, it can be standardized, which is beneficial to Standardized design, production, selection and maintenance of instruments.