Why do current transformers need to be grounded at one end?

Why do current transformers need to be grounded at one end? Current transformers are widely used in measuring instruments, relays and many other devices to convert high values to low values. In the use of current transformers, there are many things to pay attention to, current transformers need to be grounded at one end is one of them. Why current transformers should be grounded at one end? Let's start with the role of current transformers.

Role of current transformers

In the production process, current transformers can monitor the operation of the primary equipment in the system to ensure the safe operation of the power system. Current transformers are usually used to transform the large current of the primary circuit into a small secondary current proportional to it, and output the small secondary current to the secondary instrumentation, relay protection and automatic devices.

Therefore, the current transformers are the AC current source of electrical control, regulation, measurement and protection components, and also the hub of the electrical secondary circuit and primary circuit liaison.

Grounding of the secondary winding of current transformers

During the operation of current transformers, the secondary winding needs to be grounded. This is to prevent the current transformers insulation is broken, high voltage through the current transformer string into the low voltage, injury to the instrumentation and operation personnel.

If we will current transformers of the secondary winding of a point of grounding, will not affect the normal operation of the equipment, but also to protect the safety of personnel and equipment.

Therefore, the secondary winding of the current transformers must be grounded, so as to play a protective role in the high-voltage danger.

Current transformers can not be open-circuited on the secondary sideThe secondary side of the current transformers must be grounded, there is and can only be a grounding point, not allowed to have more than one grounding point, and can not be open circuit.This is because if the secondary circuit of the current transformers open circuit, then the secondary current will disappear, and then the demagnetization effect also disappears, will cause the core in the magnetic density is very high.

And the number of turns of the secondary winding is much larger than the number of turns of the primary winding, so once the secondary side of the current transformers open circuit, there will be a very high voltage, sometimes even up to thousands of volts, so not only jeopardize the secondary side of the equipment, but also endanger personal safety.

Among the various devices, the current transformers can have two main roles, one of which is the instrumentation measurement, that is, to show the amount of current in the operating equipment. Another common role of current transformers is protection, often used in conjunction with relays, when a short circuit or overload and other faults occur in the line, the current transformer sends a signal to the relay to cut off the faulty circuit, so as to achieve the purpose of protecting the safety of the power supply system. Regardless of the use of current transformers, their use needs to pay attention to safety.

Current Transformers FAQ

1. What is a current transformer, and how does it work?A current transformer (CT) is a type of transformer used to measure alternating current (AC). It works by stepping down high currents to a lower, safer value that can be measured by instruments. The CT produces a proportional current in its secondary winding, which can be used for monitoring or protection in electrical systems.2. Why do current transformers need to be grounded at one end?Grounding one end of the current transformer helps protect the system and personnel from electrical faults and high-voltage surges. Grounding ensures that any excess voltage is safely discharged to the ground, reducing the risk of insulation breakdown or damage to equipment, while also enhancing the safety of the electrical system.3. What are the typical applications of current transformers?Current transformers are used in power generation, distribution systems, and industrial environments for monitoring, metering, and protecting high-voltage circuits. They are essential in applications like energy management, load monitoring, and relay protection for transformers, motors, and other electrical equipment.4. How do I choose the right current transformer for my application?When choosing a current transformer, consider factors such as the primary current rating, accuracy class, insulation level, and physical size. Ensure that the CT is compatible with the electrical system’s requirements and that it meets the necessary safety and performance standards for the intended environment.5. How do I properly install a current transformer?During installation, ensure that the CT is correctly oriented with the primary conductor passing through the core. Connect the secondary terminals to the measuring or protection device, and ensure one end is securely grounded. Follow the manufacturer’s guidelines for proper installation, and always adhere to safety protocols to avoid damaging the transformer or associated equipment.