This post covers How is the voltage transformer connected to the circuit?, How are voltage transformers connected to the circuit?, Why is the voltage transformer connected in parallel to the circuit?
How is the voltage transformer connected to the circuit?
A voltage transformer, also called a potential transformer (PT), is connected to the circuit in a specific manner to accurately measure voltage without affecting the operation of the circuit. It is usually connected in parallel with the circuit whose voltage is measured. This parallel connection ensures that the voltage transformer experiences the same voltage as the circuit, allowing it to step down the voltage to a lower, manageable level suitable for measurement by meters or protection devices.
How are voltage transformers connected to the circuit?
Voltage transformers are connected to the circuit by placing them at the points where the voltage is to be measured. This connection involves connecting the primary winding of the transformer directly to the high voltage points of the circuit. The secondary winding, which provides the reduced voltage output, is connected to measuring instruments or protective relays. The design of the voltage transformer ensures that the voltage across its primary winding is proportional to the measured voltage, while the secondary winding delivers a lower standardized voltage.
A voltage transformer is connected in parallel to the circuit because this connection configuration allows it to measure the voltage directly across the circuit without altering the operation of the circuit. By being in parallel, the voltage transformer maintains the same voltage as the circuit while stepping it down to a lower value on the secondary side. This method ensures accurate measurement and monitoring of circuit voltage and is essential for measurement and protection applications.
Why is the voltage transformer connected in parallel to the circuit?
A voltage transformer works on the principle of electromagnetic induction. It consists of two windings: the primary winding, which is connected across the high voltage circuit, and the secondary winding, which provides a lower output voltage. When alternating current flows through the primary winding, it creates a magnetic field in the transformer core. This magnetic field induces a proportional voltage in the secondary winding, which is a lower voltage suitable for measurement by instruments or for use in protective relays. The turns ratio between the primary and secondary windings determines the level of voltage reduction.
A current transformer is connected to the circuit in a way that allows it to measure the current flowing in a conductor while providing isolation between the high-current circuit and the measuring devices. To connect a current transformer, the primary conductor (or bus bar) passes through the current transformer core, which effectively forms the primary winding. The secondary winding of the current transformer is connected to measuring instruments, relays or meters. This configuration allows the current transformer to produce a reduced current in the secondary winding that is proportional to the current flowing in the primary conductor, allowing precise measurement and protection.
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