What is a Synchronization Cabinet? Structure and operating mechanism

BTB Electric

• News
• Dec 17, 2024
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A synchronization cabinet serves the critical function of integrating multiple independently operating generators into a single, synchronized power system—ensuring their operation in parallel and unity. This technical solution enhances overall system reliability and achieves fuel savings by optimally distributing load among generators.

What is a synchronization cabinet?

The synchronization cabinet  is an electrical cabinet that synchronously connects a generator set or multiple units to the transmission grid of 22kV, 35kV and 110kV medium voltage. The cabinet is designed to synchronize the transmitters working together without causing problems on the generator, turbine, and without interfering with the power grid. 

In power plants, the synchronization cabinet provides the ability to control the speed and excitation so that the generator is qualified to shut off. Depending on the system requirements, the synchronization cabinet can adjust the synchronous mixing process in an automatic way or combine synchronous mixers and manual controls to backup the automatic mixing system. When there are two or more generators that need to be synchronized, the control circuit in the cabinet will consist of a relay and a switching unit to convert the voltage transformers and control circuits for the generators.

Synchronization cabinet structure

Depending on the requirements of the system, the structure of the synchronization cabinet will include an automatic synchronizer, a testing relay and other supporting equipment to ensure that the synchronization takes place smoothly, without affecting the generator turbine and the connected grid system. Inside the cabinet, there is 1 compartment for the synchronous mixer, 1 main control cabinet compartment and control cabinets for each transmitter.

Parameters installed on the synchronization cabinet:

• Install the synchronous draw test relay: the phase deviation of 1 angle is not more than 20 degrees.
• Automatic synchronizer setting: frequency deviation is not more than 0.3Hz, voltage deviation is not more than 5%, phase angle deviation is not more than 5 degrees when synchronizing

Modern synchronization cabinets are designed in a modular form, flexible in changing and increasing capacity while still ensuring a very high synchronization speed. The cabinet is managed through a computer directly wired or LAN internet. In addition, the cabinet also integrates a screen, buttons, keys, levers, indicator lights, and horns,.. on the surface.

Main Functions of synchronization cabinet

The main function of the synchronization cabinet is to bring multiple generators operating independently into a parallel and uniform working system. This solution aims to improve the reliability and fuel economy of the system.

The specific functions of the synchronization cabinet are as follows:

• Manually start the backup generator, synchronize with the overloaded system.
• Load management, work assignment for generators.
• Adjust the speed and excitation for the generator.
• Shut off the generator when necessary.
• Notify and protect the electrical system when overloaded, low voltage, overcurrent, reverse power, leakage.
• Measure electrical parameters such as current, current properties, voltage, power, power factor,..
• Notify and protect the engine when it fails to start, low viscosity pressure, overspeeding, coolant temperature is too high,…
• Communication and remote control, storage and analysis of operational data.

Synchronization cabinet operation methods

The synchronization cabinet has 2 operating methods: automatic synchronizing and precision synchronizing

Automatic synchronization uses PLC to synchronize, specifies the allowable interval of synchronization, specifies phase gain and frequency, uses synchroning relay, and automatically sends the load to the transmitter. When conducting automatic synchronization, the entire rotation angle of the generator must be approximately the rotation angle speed of other transmitters in the same system. When closing 1 unit that is operating in parallel, the other unit is not triggered.

Accurate synchronization is done manually through the following steps:

• Step 1: Bring the voltage of the generator (UF) to the value equal to the voltage of the network (UHT)
• Step 2: Adjust the rotation speed of the generator (wF) to be greater than the rotation angle speed of the network (wHT)
• Step 3: Align the phase angle of the generator voltage vector and the network voltage equally at the time of closing the cutter. At that time, the standard phase deviation angle between the transmitter voltage vectors and the network needs to reach d >> 0.

Note that before operating the synchronous cabinet, the system needs to meet the following requirements:

• The phase deviation angle of the synchronous relay is less than 20 degrees.
• The frequency deviation is not more than 0.3 Hz, the voltage difference is not more than 5%, and the phase deviation angle when synchronizing is not more than 5 degrees.
• The voltage difference of the synchronous cabinet ranges from 80% to 110% of the rated voltage value.

Application of synchronization cabinet

The synchronization cabinet is used when the system has redundant generators that need to be put into the grid in sync with other generators. This industrial cabinet plays an important role in ensuring the continuous and smooth operation of the power generation system. When the main power supply fails, the synchronization cabinet controls the backup generators to operate, synchronize and share the load to compensate.

The synchronization cabinets are applied in industrial parks, factories, factories, factories, commercial centers, office buildings, hospitals, airports, ports, railway stations,… In general, they are places that require continuous power supply for the load or places that often experience sudden power outages.

The synchronization cabinets are an optimal solution to improve the reliability and efficiency of electrical systems. Refer to more information about other industrial electrical cabinets that have been compiled by BTB Electric.