JP3315783B2 - Generator stop device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a generator stopping device.

[0002]

2. Description of the Related Art An example of a conventional generator stopping device will be described with reference to a generator stopping control block diagram of FIG. As shown in FIG. 3, there are a generator operation state 1, reactive power control 2, active power control 3, generator protection stop control 4, reactive power 0 detection 5, active power 0 detection 6, and generator disconnection control 7.

In the generator stop control block diagram configured as described above, when the generator is in the generator operating state 1 and a stop command is given, the reactive power control 2 and the active power control 3 are executed. In the reactive power control 2, the reactive power of the operating generator is detected, and the excitation of the generator is adjusted until the reactive power becomes zero. The reactive power 0 state is performed by reactive power 0 detection 5. In the active power control 3, the active power of the operating generator is detected, and the driving force of the generator is adjusted until the active power becomes zero. This active power 0 state is performed by active power 0 detection 6. When both the conditions of the reactive power 0 detection 5 and the active power 0 detection 6 are established, the generator is disconnected from the system by the generator disconnection control 7 and stopped. When a failure is detected during operation and stoppage of the generator, the generator disconnection control 7 is operated unconditionally by the independent generator protection stop control 4, and is stopped after the generator is disconnected from the system. Let it.

[0004]

Conventionally, the reactive power and active power of a generator are reduced regardless of the voltage and frequency of the system. Therefore, when the system is small and weak, the reactive power reduction control by the reactive power control 2 lowers the system voltage outside the voltage fluctuation range. Active power control 3
In the active power reduction control, the balance between the power generation amount and the load is lost, and the system frequency is deviated from the frequency fluctuation range.

As described above, when the generator is stopped, there is a danger that the system may be greatly shaken, causing a failure of a load connected to the system and a protection trip of another generator, resulting in a system shutdown. In addition, in order to reduce system fluctuations, it is necessary to stop automatic generators, stop the generators manually, adjust the reactive power and active power while linking with other power plants, and then stop the generators. Was.

That is, when the generator is stopped and controlled, if the system in which the generators are arranged in parallel is weak, the system voltage is lowered outside the voltage fluctuation range. There is a drawback of generating system fluctuation such as lowering the system frequency out of the frequency fluctuation range, and depending on the fluctuation width and time, there is a danger that the system may go down due to a protective trip of another generator.

[0007] The present invention is intended to minimize the fluctuation of the system in which the generators are arranged in parallel when the generator is stopped, and to keep the system stable. An object of the present invention is to eliminate the manual adjustment control by the automatic adjustment control, simplify the control, and improve the reliability of the generator stop control.

[0008]

In order to achieve the above object, according to the present invention, when a command to stop operation of a generator is output, adjustment control of reactive power and adjustment of active power of the generator are performed. Control means for reducing the reactive power and active power of the generator to zero within the set voltage fluctuation range and the set frequency range; and the reactive power and active power being reduced to zero by the first calculation means. In the process of decreasing, when the voltage and frequency of the generator deviate from the set voltage fluctuation range and the set frequency range, the adjustment control of the reactive power and the active power is stopped until the voltage and the frequency return to the respective ranges. A second arithmetic means for outputting an alarm in accordance with each control if the system does not return after a lapse of a certain time; and reactive power and active power after a lapse of a certain time after the alarm is output by the second arithmetic means. If not reduced, the reactive power and active power are reduced to zero irrespective of the conditions of the set voltage fluctuation range and the set frequency range, and it is detected that each power has become zero, and the generator is disconnected from the system. And a third calculating means for disconnecting.

According to a second aspect of the present invention, in the first aspect, the generator is stopped based on the reactive power. Claim 3
In the invention of the first aspect, the generator is stopped based on the active power.

According to a fourth aspect of the present invention, in the first aspect of the present invention, when at least one of the reactive power and the active power is not reduced to zero after a lapse of a predetermined time after the alarm is output by the second arithmetic means, The operation of the generator is continued without receiving the operation stop command of the generator. According to a fifth aspect of the present invention, in the fourth aspect, the generator is stopped based on the reactive power.

[0011]

When the operation stop command of the generator is output, the reactive power adjustment control and the active power adjustment control are performed. In the reactive power adjustment control, after detecting the presence or absence of the reactive power, if the generator has the reactive power, the reactive power reduction control signal is output. If the system voltage drops due to the reactive power reduction control and deviates from the set range, and if the state continues, an alarm is issued and attention is given to keep the system voltage within the allowable range by controlling the operation of the other generators. If the reactive power cannot be reduced to 0 with the system voltage lowered even after the alarm, the reactive power is reduced irrespective of the system voltage fluctuation.

In the active power adjustment control, after detecting the presence / absence of active power, if the generator has active power, an active power reduction control signal is output to the generator driver. The active power reduction control lowers the system frequency, deviates from the set range, and if the state continues, issues an alarm and warns the operator to keep the system frequency within the set range by controlling the operation of other generators. Even after this warning, if the active power cannot be reduced to 0 with the system frequency lowered, the active power is reduced irrespective of the frequency fluctuation of the system. It detects that both the reactive power and the active power have been reduced to 0 within the set range for both the system voltage and the system frequency, and disconnects and stops the generator. If neither the reactive power nor the active power can be reduced to 0 within the set time, the reactive power and the active power are set to 0 regardless of the voltage fluctuation and the frequency fluctuation of the system, and the generator is disconnected and stopped.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a generator stop control block diagram showing one embodiment of the present invention. As shown in FIG. 1, the generator operation state 1, reactive power control 2, active power control 3, generator protection stop control 4, reactive power detection 5, active power detection 6, and generator disconnection control 7, and their functions are The function is the same as that shown in FIG. 3, and the description is omitted here.

The difference from FIG. 3 is that a function including a stop mode switching control 8, a reactive power adjustment control 9, and an active power adjustment control is added. Next, the operation of this embodiment will be described.

When the generator is stopped from the generator operating state 1, the stop mode switching control 8 allows the user to select either the normal stop mode or the system stabilization stop mode shown in FIG. First, the stop mode switching control 8 is set to the system stabilization stop mode, and when a stop command is issued to the generator, the reactive power adjustment control 9 and the active power adjustment control 10 are executed.

In the reactive power adjustment control 9, it is determined whether or not the reactive power of the generator is substantially zero. It has a predetermined width in design. If reactive power is detected within this predetermined range, it is determined to be zero. The same definition applies to the control of active power, which will be described later. 0
If it is not determined, the reactive power is reduced to zero by executing a control for reducing the reactive power on condition that the system voltage is within the allowable range. If the system voltage has already deviated from the permissible range and is low or falls below the permissible range in the process of reducing the reactive power, the control for reducing the reactive power is stopped and the recovery of the system voltage is waited. If the system voltage returns to within the allowable range, the reactive power is reduced again to reduce the reactive power to 0, but if the system voltage does not return to the allowable range within the preset time T1, an alarm is issued and the operator is warned. To inform the system of the need for voltage control. In accordance with this alarm, the operator stops the reactive power adjustment control of the other generators to return the system voltage to within the allowable range when the system voltage returns to within the allowable range by this adjustment control, and stops the reactive power of the generator. Is executed again.

If the alarmed operator fails to return the system voltage to within an allowable range within a predetermined time T2, the operator gives up the system stabilization stop, shifts to the normal stop mode, and disables the system. The power control 2 controls the reactive power of the generator to zero irrespective of system voltage fluctuations.

On the other hand, in the active power adjustment control, it is determined whether or not the active power of the generator is substantially zero. If the active power is not zero, the active power is controlled on the condition that the system frequency is within an allowable range. The reduction control is executed to reduce the active power to zero.

If the system frequency has already deviated from the allowable range and is low and falls below the allowable range in the process of reducing the active power, the control for reducing the active power is stopped and the recovery of the system frequency is waited. When the frequency of the system returns to within the allowable range, the active power is reduced again and the active power is set to 0.
If the frequency of the system does not return to the allowable range within the preset time T3, an alarm is issued to notify the operator of the necessity of controlling the frequency of the system. In accordance with this warning, the operator performs active power adjustment control of another generator to return the frequency of the system to within an allowable range. When the system returns to the allowable range by this adjustment control, control for reducing the active power of the generator to be stopped is executed again.

If the operator who has received the warning cannot return the frequency of the system to within the allowable range within the preset time T4, the operator gives up the system stabilization stop, shifts to the normal stop mode, and activates the system. The process shifts to the power control 3, and the active power is controlled to 0 by the active power control 3 irrespective of the frequency fluctuation of the system.

When the reactive power is slowly reduced within the voltage fluctuation range of the system by the reactive power adjustment control 9 in the system stabilization stop mode, the reactive power 0 detection 5 operates. Similarly, when the active power is slowly reduced by the active power adjustment control 10 within the frequency fluctuation range of the system, the active power 0 detection 6 operates.

Only when both the reactive power 0 detection 5 and the active power 0 detection 6 operate, the generator disconnection control 7 is executed, the parallel breaker of the generator is disconnected, and the generator is disconnected from the system and stopped. .

If the reactive power has not been reduced by the reactive power adjustment control 9 or the active power has not been reduced by the active power adjustment control 10, the process shifts to the normal stop mode and the reactive power control 2 forcibly disables the power. The power is reduced or the active power control 3 is performed to forcibly reduce the active power. Also in this case, the reactive power 0 detection and the active power 0 detection 6 operate, and if both operate, the generator disconnection control is executed, the parallel breaker of the generator is disconnected, and the generator is disconnected from the system and stopped. Let it.

The generator protection stop control 4 is a stop control independent of the system stabilization stop mode and the normal stop mode selected by the stop mode switching control 8, and is used when the generator fails. And the generator is stopped prior to the normal stop mode.

As described above, according to the present invention, when the generator is stopped, the reactive power adjustment control and the active power adjustment control are operated by selecting the system stabilization stop mode, and the reactive power and the active power of the generator are reduced. The voltage can be reduced to zero slowly within the voltage fluctuation range and the frequency fluctuation range of the system, and fluctuations of the system voltage and frequency can be minimized to keep the system stable.

If the reactive power and the active power cannot be reduced within the voltage fluctuation range and the frequency fluctuation range of the system within the set time, respectively, an alarm is issued correspondingly,
By letting the operator recognize the necessity of voltage adjustment or frequency adjustment of the system, adjustment control by another generator can be executed. Also in this case, the reactive power adjustment control and the active power adjustment control are executed, the reactive power and the active power are automatically reduced, and the generator can be stopped while keeping the system stable, so that the adjustment control can be simplified. In addition, when the reactive power adjustment control and the active power adjustment control cannot be performed within the voltage fluctuation range and frequency fluctuation range of the system, respectively, the system shifts to the normal stop mode and stops the generator, improving the control reliability. Can be done.

In the above embodiment, the generator is stopped when the reactive power adjustment control and the active power adjustment control cannot be executed within the voltage fluctuation range and the frequency fluctuation range of the system in the system stabilization stop mode. Although the control method for shifting to the normal stop mode has been described for the purpose, there is also a control method in which the generator to be stopped is operated for system stability to the last.

Another method of stopping the generator will be described with reference to FIG. FIG. 2 is a generator stop control block diagram showing another embodiment of the present invention. As shown in FIG. 2, the generator operation state 1, reactive power control 2, active power control 3, generator protection stop control 4, reactive power 0 detection 5, active power 0 detection 6,
The generator disconnection control 7, the stop mode switching control 8, the reactive power adjustment control 9, and the active power adjustment control 10 have the same functions as those shown in FIG. The difference from FIG. 1 is that a stop command reset control 11 is added.

When the generator is stopped from the generator operation state 1, the stop mode switching control 8 enables the normal stop mode or the system stabilization stop mode to be selected. When the normal stop mode is selected, the reactive power and the active power are reduced to 0 by the reactive power control 2 and the active power control 3 in the same manner as in the stop method according to the related art. Detected by detection 6, and if both are established, generator disconnection control 7 is executed to stop the generator. When the system stabilization stop mode is selected, first, in the reactive power adjustment control 9, the reactive power is slowly reduced to zero on condition that the system voltage is within an allowable range. If the system voltage falls below the permissible range, the reactive power reduction control is stopped and the system is restored. If the system voltage continues for a preset time T1 or more, an alarm is issued and the operator is prompted to control the system voltage.

After that, when the system voltage returns to within the allowable range, the reactive power adjustment control 9 for reducing the reactive power of the generator 9
Is executed again, and the voltage of the system becomes a predetermined time T
If it does not return within the allowable range within two, the stop command reset control 11 is operated to reset the stop command issued to the generator control device and return the generator to the normal power generation operation.

In the active power adjustment control 10, the active power is gradually reduced to zero on condition that the system frequency is within an allowable range. If the system frequency falls below the allowable range, the active power reduction control is stopped and the system is restored. If the time is maintained for a predetermined time T3 or more, an alarm is issued and the operator is prompted to control the system frequency.

After that, when the frequency of the system returns to within the allowable range, active power adjustment control for reducing the active power of the generator
Step 10 is executed again, and if the frequency of the system does not return to the allowable range within the preset time T4, the stop command reset control 11 is operated to reset the stop command issued to the control device of the generator to generate power. Return the machine to normal power operation.

When the system stabilization stop mode is selected by the stop mode switching control 8, the reactive power adjustment control 9 and the active power adjustment control 10 are executed at the same time, but within a preset time within the voltage fluctuation range of the system. Reactive power, active power can not be reduced within the frequency fluctuation range,
When the stop command reset control 11 is operated by any of the adjustment controls, the generator stop command is reset and the generator returns to the power generation operation even if either the reactive power 0 detection 5 or the active power 0 detection 6 is established. .

The generator protection stop control 4 in the event of a generator failure is executed independently of the system stabilization stop mode and the normal stop mode, as in the embodiment of FIG. In the embodiment of FIGS. 1 and 2, the case where the system stabilization stop mode and the normal stop mode are manually selected by the stop mode switching control has been described. The generator is stopped according to the mode, and the system automatically shifts to the normal stop mode only when the reactive power cannot be reduced to 0 within the voltage fluctuation range of the system or the active power cannot be reduced to 0 within the frequency fluctuation range by the reactive power adjustment control. By doing so, the same effect can be obtained even if there is no function of independently selecting the normal stop mode.

In the above embodiment, the case where both the reactive power and the active power are reduced to 0 before the disconnection control of the generator has been described. Even if the fluctuation to be given is within an allowable range in which the fluctuation is small, the same effect and the quick response of control can be obtained. In this case, the condition for starting the disconnection control of the generator is to detect a value within an allowable range centered on 0 instead of detecting zero reactive power and zero detecting active power.

Further, in the above-described embodiment, the case where the generator disconnection control is executed after executing both the reactive power adjustment control and the active power adjustment control has been described. The same effect can be obtained by executing the column control.

Although the above embodiment has been described with respect to the disconnection control of the generator, the same effect can be obtained by applying the present invention to the disconnection control of a pumping power plant or a synchronous phaser having a synchronous generator motor or a variable speed machine. Obtainable.

[0038]

As described above, according to the present invention, it is possible to minimize the fluctuation of the system in which the generators are arranged in parallel when the generators are stopped and controlled, thereby keeping the systems stable. Further, by automatically performing the adjustment control of the reactive power within the voltage fluctuation range of the system and the active power within the frequency fluctuation range, the manual adjustment control by the operator can be omitted and the control can be simplified.

In the case where the control of the reactive power adjustment and the control of the active power cannot be controlled within a range where the system does not fluctuate, in combination with the stop command reset control as in the embodiment of the invention, It acts as backup control and can improve the reliability of control. Even if the system is always strong, even if the system temporarily becomes weak due to a failure or periodic inspection of the generator, the system can be kept stable.

[Brief description of the drawings]

FIG. 1 is a block diagram of a generator stop control showing one embodiment of the present invention;

FIG. 2 is a generator stop control block diagram showing another embodiment,

FIG. 3 is a block diagram of a conventional generator stop control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Generator operation state 2 ... Reactive power control 3 ... Active power control 4 ... Generator protection stop control 5 ... Reactive power 0 detection control 6 ... Active power 0 detection control 7 ... Generator disconnection control 8 ... Stop mode switching control 9: Reactive power adjustment control 10: Active power adjustment control 11: Stop command reset control

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J 3/00-5/00

Claims (5)

(57) [Claims] When an operation stop command for a generator is output, the controller performs adjustment control of reactive power and adjustment of active power of the generator, and adjusts the reactive power and active power of the generator to a set voltage fluctuation range and First calculating means for reducing the reactive power and active power to zero in the first calculating means, wherein the voltage and frequency of the generator are reduced to a set voltage variation range and the set When deviating from the frequency range, the control for adjusting the reactive power and the active power is stopped until the voltage and the frequency return to the respective ranges, and when the voltage and the frequency do not return after the elapse of a certain time, an alarm is issued according to each control. A second calculating means for outputting, when the reactive power and the active power have not been reduced to zero after a lapse of a fixed time after the alarm output by the second calculating means, a set voltage fluctuation range and a set frequency Third calculation means for reducing the reactive power and the active power to zero irrespective of the surrounding conditions, detecting that each power has become zero, and disconnecting the generator from the system. Generator stop device. 2. A first arithmetic means for performing a control of adjusting the reactive power of the generator when the operation stop command of the generator is output, and reducing the reactive power of the generator to zero within a set voltage fluctuation range. And in the step of reducing the reactive power to zero by the first arithmetic means, when the voltage of the generator deviates from the voltage fluctuation range, the control of the active power is returned to the voltage fluctuation range. A second calculating means for outputting an alarm in accordance with each control when the recovery is not performed after a lapse of a certain time, and the reactive power becomes zero after a lapse of a certain time after the alarm is output by the second calculating means. If not, the third step is to reduce the reactive power to zero irrespective of the condition of the set voltage fluctuation range, detect that the reactive power has become zero, and disconnect the generator from the system. Means, comprising: Stop device for electric motor. 3. A first calculating means for performing a control of adjusting the active power of the generator when the operation stop command of the generator is output, and reducing the active power of the generator to zero within a set frequency range. In the process of reducing the active power to zero by the first calculating means, if the frequency of the generator deviates from the set frequency range, the active power adjustment control is performed until the frequency returns to within the range. A second calculating means for stopping and outputting an alarm in accordance with each control when not returning after a lapse of a certain time; and an active power decreasing to zero after a lapse of a certain time after the alarm is output by the second calculating means. If not, a third computing means for reducing the active power to zero irrespective of the condition of the set frequency range, detecting that the active power has become zero, and disconnecting the generator from the system. Power generation characterized by comprising: Machine stop device. 4. When a generator operation stop command is output, control for adjusting the reactive power of the generator and control for adjusting the active power are performed, and the reactive power and the active power of the generator are set to a set voltage variation range and First calculating means for reducing the reactive power and active power to zero in the first calculating means, wherein the voltage and frequency of the generator are reduced to a set voltage variation range and the set When deviating from the frequency range, the control for adjusting the reactive power and the active power is stopped until the voltage and the frequency return to the respective ranges, and when the voltage and the frequency do not return after the elapse of a certain time, an alarm is issued according to each control. Outputting at least one of the reactive power and the active power after a lapse of a predetermined time after the alarm is output by the second arithmetic means, and stopping the operation of the generator. Generator stop device, characterized by continuing the operation of the generator without receiving a command. 5. A first calculating means for performing a control of adjusting the reactive power of the generator when the operation stop command of the generator is output, and reducing the reactive power of the generator to zero within a set voltage fluctuation range. And when the voltage of the generator deviates from the voltage range in the process of reducing the reactive power to zero by the first calculating means, the control of adjusting the reactive power is stopped until the voltage returns to within the range. The second arithmetic means outputs an alarm in accordance with each control if it does not return after a lapse of a certain time, and the reactive power is reduced to zero after a lapse of a certain time after the alarm is output by the second arithmetic means. A generator stopping device that does not accept the operation stop command of the generator when it is not present, and continues the operation of the generator.