Automatic Synchronize cabinet and principle

一、General overview:

The automatic synchronous diesel generator set parallel system synchronizes two or more generators to the same bus through an automatic electronic control device. Each generator control panel has dedicated equipment, while the common equipment is placed in the output cabinet. Power is distributed through a power balancer and an automatic voltage regulator

2. Combined cabinet equipment and structure

1. Synchronous controller

1.1 Speed governor:

The regulator is equipped with the diesel set and is controlled by the central controller when running in parallel, so that the speed and load of the generator are controlled within the allowable error range of the set value.

1.2 Automatic synchronizer:

The synchronizer compares the phase and frequency of the generator diesel engine that has not yet been connected to the bus. When a phase difference occurs, a current signal is issued to accelerate or slow down the generator speed according to whether the generator diesel engine phase angle leads or lags the bus phase angle. The size of the signal is proportional to the phase difference. When the phase and frequency match a specific "lock" time within a limited range, the synchronizer will close a set of normally open contacts and control the closing load air switch through a relay.

1.3 Central controller:

The controller integrates electronic speed regulator and power balancer. When the vehicle is not connected to the grid, the controller receives the signal of the automatic synchronizer and changes the running speed of the diesel generator set to make the voltage frequency and phase of the left and right generator sets equal to the voltage frequency and phase of the bus. After the vehicle is connected to the grid, the actual load active power of the diesel generator power unit is compared with the average equivalent voltage value of the total load, and the voltage frequency of the generator set is compared with the set frequency. Then the difference signal obtained from the two comparisons is superimposed and the speed control signal is output, so that the active load can be set according to the pre-set load distribution parameters.

1.4 Slow synchronization display (S):

Once the voltage and frequency are close to the same, the display indication will slowly change back and forth between "-" and "+". When the waveforms of the generator and the bus are consistent, the display will show that synchronization is occurring in the "same phase" position.

2. Instruments

2.1 Power meter (CP96): The power meter detects the load of the generator.

2.2 AC ammeter (CP96): The phase current detected by the ammeter.

2.3 AC voltmeter (CP96): The voltmeter detects the line voltage or phase voltage selected by the "voltage selection switch"

2.4 Frequency meter (CP96): The frequency meter detects the voltage frequency

3. Synchronous protector

3.1 Reverse power protection: The reverse power protection device monitors the power load of the generator,

If the reverse power reaches a preset level (adjustment range is 2%-20%) within a predetermined time (adjustment range is 2%-20%), the load switch opens. Prevent one generator from being dragged down by another generator. These presets are usually five seconds, and the reverse power is less than 20%

3.2 Emergency stop protection device: When the Mitsubishi generator or parallel system is in an emergency, press the emergency switch of the parallel cabinet, the load switch opens in time, and the unit stops.

4. Indicator lights on the control cabinet

4.1 Generator fault: The indicator light indicates that the central generator has a low oil pressure or high water temperature fault

4.2 Backflow fault: The indicator light is on, indicating that a backflow fault occurs between the synchronous diesel generator set and the AC generator set during parallel operation

4.3 Standby indication: When the indicator light is on, it indicates that the Fujian generator is in standby state

4.4 Operation indication: After the China address generator is operating normally, the indicator light is on

4.5 Opening indication: When the light is on, it indicates that the load air switch is in the opening state.

4.6 Closing indication: When the light is on, it indicates that the load air switch is in the closing state.

4.7 Power generation indication: When the light is on, it indicates that the seesaw generator has output voltage to the cabinet.

3. System operation

1. Manual operation

1.1 Before starting, check whether the phase sequence is correct. The common part control switch (SA3) cannot be turned off before confirming the phase sequence. This step can be omitted when operating after the unit is debugged.

1.2 Set the selector switch on the operation screen to the "MAN" position.

1.3 Start the first generator set.

1.4 After the generator set starts normally, press the "Close" button and the air switch closes.

1.5 Start the second diesel generator set.

1.6 After normal power generation, check whether the voltage and frequency of the two machines are consistent. If not, adjust them to be consistent. Press the "Close" button, the automatic synchronizer detects synchronization and instructs the switch to close.

1.7 During the shutdown process, if the vehicle is connected in parallel with the load, in order to avoid opening the load air

Shutdown and damage to the generator, and maintain the power supply quality of other generators, and the cabinet has a "soft" unloading function, adjust the speed fine-tuning, reduce the speed of the machine that needs to be stopped, and gradually reduce the load to a certain value. After that, press "Stop" to stop.

1.8 In case of emergency, press the emergency stop switch, and the generator will start and stop immediately.

2. Automatic operation

2.1 Set the selection switch on the operation screen to the "Automatic" (AUTO) position.

2.2 After the city power is cut off, the first generator set starts automatically. (It can also be operated manually)

2.3 The first unit starts normally, delays for 5 seconds (adjustable for normal operation of the unit), and is directly connected to the main bus for power generation.

2.4 Two seconds after the first unit starts, the second unit starts automatically, delays for 5 seconds (adjustable for normal operation of the unit), and its speed is controlled by the synchronizer. When the unit voltage frequency and phase are the same as the bus voltage frequency phase, the synchronizer sends a closing signal,

2.5 In the single-unit operation state, if one of the units fails, the second unit starts automatically.

2.6 When the load air switch of the generator set control panel of the parallel vehicle is closed, the power balancer starts to work and automatically balances the generator power of each running load according to the pre-set load distribution parameters

2.7 When shutting down, in order to avoid damage to the load air switch and generator, and to ensure the power supply quality of other generators, if the parallel system and load are used together, and the parallel cabinet has a "soft" unloading function, the speed adjustment is fine-tuned to reduce the speed of the machine that needs to be shut down. When its load gradually decreases to a certain value, press the "on" button to shut down.

2.8 In case of emergency, press the emergency stop switch, and the generator will immediately turn on and stop.