JPH0556699A - Parallel/parallel-off control system for a plurality of generators - Google Patents

Abstract

PURPOSE:To avoid function of an overspeed protector against overshoot of rotational speed which occurs immediately after start of an engine at an initial set speed by means of a plurality of generators which repeat parallel and parallel-off operations while being driven with a ground Diesel engine having predetermined speed drop rate. CONSTITUTION:Generators 1, 2 are connected, respectively, through generator circuit breakers 3, 4 with a load. Frequency of the generator 1 is detected at a frequency detecting section 5 through a PT and delivered to a governor control section 6. Stop operation is carried out by opening the load by means of the generator circuit breaker 3, resetting the generator frequency detected at the frequency detecting section 5 at a rated value after no-load operation, and then stopping the engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for resetting the frequencies of a plurality of generators when they are operated in parallel, and more particularly to a speed governor for driving the generators by a land diesel engine. Regarding control.

[0002]

2. Description of the Related Art When a generator is driven by a land diesel engine or a gas turbine engine, the governor body may be controlled by an isochronous method using an electrohydraulic speed governor or the like. In this case, although the active power balance control circuit during parallel operation becomes complicated, the governor itself may be of any type such as electrohydraulic type, mechanical hydraulic type, mechanical type, etc. Can be adopted, and it is not necessary to take any action in the control circuit on the electric side. FIG. 4 is a characteristic diagram of such a troop method. In the figure, A shows the rotation speed characteristic at 0% load, B shows the rotation speed characteristic at 100% load, 0
The difference in the rated frequency at% is set as the troop (speed droop rate).

[0003]

However, in the above conventional parallel generator, when the parallel setting is canceled or the engine is stopped for some reason when the load setting value of the governor is the maximum value,
If the engine is restarted in this state, as shown in FIG. 5, an overshoot of the rotation speed (frequency) immediately after the start occurs, and the emergency stop may occur due to the operation of the overspeed protection device. The present invention has been devised in view of such a problem, and in a plurality of generators that repeat parallel and parallel disconnection, against the overshoot of the rotation speed that occurs immediately after the engine is started with the initial setting value of the speed. It is an object of the present invention to provide a parallel / parallel disconnection control method that can avoid the operation of an overspeed protection device.

[0004]

Means for solving the above problems in the present invention include a diesel engine, a gas engine or a diesel engine equipped with a mechanical, electric or electronic speed governor having a predetermined speed droop rate. In a governor control system for a plurality of generators driven by a gas turbine engine, which performs unit number control that repeats parallel and parallel disconnection and load balance control when parallel, a frequency detection unit that detects the frequency of each generator And a governor control unit that controls the frequency, and the stop operation is a parallel / parallel disconnection control that first releases the load, resets the generator frequency after no-load operation to the rated speed, and then stops the engine. It depends on the method.

[0005]

According to the present invention, when the generator is stopped after operating at maximum load, the generator circuit breaker is opened by a stop command, while the engine is operated for no load for a certain period of time for warming and cooling. It controls the governor by detecting the generator frequency,
It resets to the rated frequency.

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, generators 1 and 2 are each connected to a load via a generator breaker 3 or 4. The frequency of the generator 1 is detected by the frequency detection unit 5 via PT,
It is sent to the governor control unit 6. The generator 2 also has a similar configuration, but is omitted for convenience of the drawing. Although the number of generators is 2 in this embodiment, it goes without saying that a plurality of required generators may be used.

FIG. 2 is a block diagram showing the governor control unit 6 of the above embodiment in more detail. In the figure, the generator 1,
The generator breaker 3, the frequency detection unit 5, and the governor control unit 6 are the same as those shown in FIG. 1, and the governor control unit 6 includes the deviation detection unit 21, the governor control unit 22, and the engine stop. Command means 2
Equipped with 3. When performing the stop operation with this device, first the load is released by the generator breaker 3, the load detector is operated without load, and then the frequency detector 5 detects the frequency of the generator 1.
The deviation detection means 21 compares the frequency with the rated frequency, and if there is a deviation, the speed governor control means 22 resets the speed to the rated speed, and then the engine is stopped by a command from the engine stop command means 23.

FIG. 3 is a characteristic diagram showing an embodiment of the present invention. In the figure, if a stop command is issued while the target generator is operating at the point P1 of the rated state, the engine speed set value by the governor also remains at the rated state of 100% load and rated frequency. However, when restarting in this state, assuming that the troop of the governor is 6%, it must be the P2 point corresponding to the load of 0% after completion of the start, and 53 Hz when the rated frequency is 50 Hz, Rated frequency is 60
In the case of Hz, since there is a deviation of 63.6 Hz, the engine may cause the overshoot just before entering the speed control speed. Since it stops after making it correspond to, there is little possibility that the overspeed protection relay against overshoot operates to make an emergency stop. In the case of isochronous control, the rated frequency is always maintained between 0% and 100%, but the load setting control circuit becomes electrically complicated during parallel operation, so sg that requires a constant frequency is a single unit. It is common to drive.

The following effects are apparent in this embodiment.

(1) After restarting, even if there is no load, the start is completed at the rated speed, so when other generators are operating at actual load, it is easy to make a synchronous input to them.

(2) For the same reason, after the restart, the operation of the overspeed protection device against the overshoot of the rotation speed immediately after the start is prevented.

[0012]

As described above, according to the present invention, in a plurality of generators that repeat parallel and parallel disconnection, the overshoot of the rotation speed that occurs immediately after the engine is started with the initial setting value of the speed is suppressed. It is possible to provide a parallel and parallel disconnection control method capable of avoiding the operation of the overspeed protection device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is a characteristic diagram of an example of the present invention.

FIG. 4 is a characteristic diagram of a conventional example.

FIG. 5 is a characteristic diagram of a conventional example.

[Explanation of symbols]

1, 2 ... Generator, 3, 4 ... Generator breaker, 5 ... Frequency detection unit, 6 ... Governor control unit, 21 ... Deviation detection means, 22 ...
Governor control means, 23 ... Engine stop command means.

Claims (1)

[Claims] Claims: 1. A diesel engine, a gas engine, or a gas turbine engine equipped with a mechanical, electric, or electronic speed governor having a predetermined speed droop rate, and driven in parallel and in parallel with parallel control of the number of units. In a governor control system for a plurality of generators that performs load balancing control at the time, a frequency detection unit that detects the frequency of each generator and a governor control unit that controls the frequency Is a parallel / disconnection control method for multiple generators operating in parallel, which is characterized by first releasing the load, resetting the generator frequency after no-load operation to the rated speed, and then stopping the engine.