Secondary electrical equipment refers to low-voltage electrical equipment used to monitor, control, regulate, and protect primary equipment (such as generators, transformers, circuit breakers, etc.), and to provide operating condition or production command signals to operation and maintenance personnel.
If primary equipment directly involved in power generation and transmission is the "skeleton and muscles" of the power system, then secondary electrical equipment is its "neural network" and "intelligent central hub." It does not directly participate in the high-current transmission of the main circuit, but rather ensures the safe, reliable, and economical operation of primary equipment through low-voltage circuits.
Classification of Secondary Equipment
Measuring and metering equipment: such as ammeters, voltmeters, wattmeters, and energy meters, used to indicate and record the operating parameters of the primary system in real time.
Relay protection and automatic devices: such as various relay protection devices, fault recording devices, and automatic reclosing devices. They can react quickly when a system fault occurs, isolating the fault or restoring power supply.
Control and signaling components: such as control switches, buttons, indicator lights, and audible alarm devices (bells, sirens), used for remote operation of primary equipment and feedback of its operating status.
Instrument transformers: including current transformers (CTs) and voltage transformers (PTs). They act as "bridges" connecting the primary and secondary systems, proportionally converting the high voltage and high current on the primary side into standard low voltage and low current on the secondary side for use by measuring and protection equipment.
Operating power supply systems: including DC power supply systems (such as battery banks and rectifiers) and AC power supply systems, providing a stable and reliable power supply for control, protection, and signaling equipment.
Connection and auxiliary equipment: such as control cables, connecting wires, terminal blocks, fuses, etc., used to connect the above equipment into a complete electrical circuit.
The electrical circuit formed by the interconnection of these secondary devices, which monitors, controls, regulates, and protects the primary equipment, is collectively called a secondary circuit (or secondary wiring).
In summary
In summary, although secondary equipment does not directly transmit large currents or high voltages, it ensures the safe operation of primary equipment through a closed-loop logic of "sensing-judgment-execution," serving as a core support for the intelligence and automation of power systems. In modern substations, secondary equipment is gradually developing towards digitalization (such as intelligent terminals and merging units), networking (IEC 61850 protocol), and integration (comprehensive protection devices replacing traditional relays).
VTZ-15/T5000-63 indoor high-voltage generator circuit breaker
VTZ-15/T5000-63 indoor high-voltage generator circuit breaker is a vacuum circuit breaker designed for generator outlets in 15 kV and lower, three-phase AC 50 Hz systems. It is primarily utilized in the plant auxiliary circuits of small to medium-sized hydroelectric generator units, thermal power generators, new energy generation systems, and industrial facilities-such as those in the chemical and processing sectors-that operate with their own captive power generation capabilities.
Shaanxi West Power Tongzhong Electrical Co., Ltd. is a leading manufacturer with over 20 years of experience, specializing in high quality 7 to 40.5kV vacuum circuit breakers, switchgears, and a wide range of electrical products.
Our advanced manufacturing process ensures reliable, durable solutions, especially our VTZ series vacuum circuit breakers, which are maintenance-free for up to 20 years. With a team of expert technicians, we excel in R&D, manufacturing, and after-sales service for both high and low voltage equipment, delivering excellence at every stage.
Contact: Ms.Grace Liu (International Sales Manager)
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Email:xdtz04@westpowerelectric.com
