Magnetic Voltage Transformer

A voltage transformer (VT), also known as a potential transformer (PT), is an electrical device used to step down or step up the voltage level in an AC (alternating current) electrical system. It is designed to safely measure and control high voltage by reducing it to a lower, more manageable level. This allows measurement devices (such as voltmeters) or protection relays to operate with safe voltage values, even when the primary system operates at very high voltages.

Key Functions of Voltage Transformers:

1. Voltage Scaling: VTs convert high voltage to a lower, proportional voltage that can be measured safely and accurately. For instance, if the primary voltage is 11 kV, the VT might step it down to 110 V for measurement.

2. Isolation: It electrically isolates the measurement or control devices from the high-voltage circuit, providing protection against electrical shock and equipment damage.

3. Accuracy: VTs are designed to provide precise and stable voltage transformation, making them essential for accurate voltage measurement and monitoring in power systems.

Construction:

Voltage transformers typically consist of:

• Primary winding: Connected to the high-voltage circuit.

• Secondary winding: Provides the scaled-down voltage for measurement or relay protection.

• Core: Usually made of laminated silicon steel to minimize energy losses due to eddy currents.

Applications:

• Metering: Used in power distribution systems for accurate voltage measurement.

• Protection: VTs are also used in relay circuits to detect faults or abnormal voltage conditions.

•System Monitoring: Helps in real-time monitoring of the electrical network's voltage levels.

In summary, a voltage transformer is an essential component for safely managing high voltage systems, allowing for measurement, protection, and control at a manageable level.