KYN28-12 is divided into incoming line cabinets, outgoing line cabinets and PT cabinets. What are their respective functions?

2025-10-31

1:KYN28-12 Incoming Feeder Panel / Main Power Input Panel

The Incoming Feeder Panel is the main gateway for electrical power entering the Switchgear system. Its primary function is to receive and distribute incoming high-voltage power from an external source, such as a transformer or the utility grid.

Key Functions:

Power Reception: It connects to the upstream power source and brings high-voltage electricity (at 12kV) into the switchgear lineup.
Circuit Protection: It is equipped with a powerful circuit breaker (usually a vacuum circuit breaker) to protect the entire system from major faults like short-circuits and overloads.
Main Isolation: It provides a central point for isolating the entire downstream switchboard from the main power supply for maintenance or in case of an emergency.
Measurement and Control: It often includes current transformers (CTs) and voltage transformers (VTs) for metering power consumption, monitoring electrical parameters (current, voltage, power), and providing signals for protection relays.
In simple terms: This is the "main entry point" of the system, responsible for receiving and disconnecting the main power supply.

2: KYN28-12 Outgoing Feeder Panel / Distribution Feeder Panel

The Outgoing Feeder Panel is responsible for distributing electrical power from the main busbar to various downstream loads or circuits.

Key Functions:

Power Distribution: It takes power from the common main busbar and routes it through individual circuits to supply different sections of the facility, such as transformers, motors, or other sub-distribution boards.
Individual Circuit Protection: Each outgoing feeder is equipped with its own circuit breaker (or a combination of a load switch and fuses) to protect its specific branch circuit from overloads and short-circuits without affecting other feeders.
Localized Control: It allows for independent control and isolation of specific loads. This means you can turn off power to one machine or area for maintenance while keeping the rest of the system energized.
Monitoring: Each feeder typically has its own set of current transformers for monitoring the load current.
In simple terms: This is the "branch point" of the system, responsible for safely distributing electricity to various power-consuming areas or devices.

3:KYN28-12 Voltage Transformer (VT) Panel / Potential Transformer (PT) Panel

The Voltage Transformer Panel does not directly handle main power distribution. Instead, it serves a critical role in system monitoring, protection, and control by transforming high voltage to a safe, standardized, low voltage.

Key Functions:

Voltage Transformation: It uses Potential Transformers (PTs) or Voltage Transformers (VTs) to step down the system voltage (e.g., 12kV) to a lower, safe standard value (typically 110V or 100V) suitable for instruments and protective devices.
Metering and Measurement: It provides the scaled-down voltage signal to voltmeters, power meters, and energy meters for accurate measurement and display of system voltage.
Protection Relaying: It supplies voltage signals to protection relays (like under-voltage or over-voltage relays) and automatic control devices, enabling them to function correctly.
Synchronization: In systems with multiple power sources, the PT panel provides the necessary voltage signals to perform synchronization checks.
Providing Control Power: It often includes a power transformer that supplies AC operating power for the switchgear's control circuits.

In simple terms: This is the "monitoring and signal center" of the system. It does not distribute power but provides precise voltage signals and operating power for the measurement, protection and control systems.