JPH05219800A - Method for protecting generator - Google Patents

Abstract

PURPOSE:To obtain the protecting method for a generator without increasing a cost, when abnormal states are generated on voltage feedback control, current feedback control, or field current feedback control. CONSTITUTION:A voltage deviation detector 18 for comparing generator output voltage(AC) and the rectified voltage(DC) with each other is set, and when a deviation exceeds a fixed value, then an AVR 9 is controlled, and a generator is stopped. In the same manner, a current deviation detector 19 is set, and an ACR 10 is controlled, and the generator is stopped. By the output of an overvoltage detector 20, a field current regulator 13 is controlled, and the generator is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to feedback control of output voltage,
In an AC generator that is performing feedback control of output current or field current feedback control, when an abnormality occurs in those feedback controls, stop the operation of the generator to protect it. It concerns protection methods.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a conventional method of protecting a generator. In the figure, 1 is an armature winding of a generator to be protected, 2 is an AC voltage detector, 3 is an AC current detector, 4 is a rectifier, 5 is a DC voltage detector, 6 is a DC current detector, 7 is a generator field winding, 8 is an output voltage setting device, 9 is an automatic voltage regulator (AVR), 10 is an automatic current regulator (ACR), 11 is an overvoltage detector, 12 is an overcurrent detector, 13 Is a field current regulator, 14 is an overcurrent detector, 1
Reference numeral 5 is a field current detector, 16 is a voltmeter, and 17 is an ammeter.

In the generator, feedback control of the output voltage and
Conventionally, the protection of the generator at the time of the abnormality is performed as follows. That is, the AC voltage which is the output of the generator is detected by the AC voltage detector 2, and the voltage set by the output voltage setting unit 8 is taken into the AVR 9, and the AVR 9 outputs a regulated output so that both voltages match, which is It joins the field current controller 13 via the ACR 10 and adjusts the field current of the generator.

It is assumed that, while the output voltage of the generator is being feedback-controlled in this way, the overvoltage detector 11 detects that the AC voltage, which is the output of the generator, has become an overvoltage. If the feedback control of the output voltage is functioning normally, the output voltage of the generator should not be overvoltage. This means that the feedback control of the output voltage is abnormal. Therefore, since the generator is destroyed as it is, the detection output of the overvoltage detector 11 instructs the AVR 9 to stop the operation of the generator to protect it. At the same time, the voltmeter 16 is monitored and necessary measures are taken.

Further, in the generator, the feedback control of the output current and the protection of the generator when there is an abnormality have been conventionally performed as follows. That is, the output current of the generator is detected by the AC current detector 3 and the output current of the AVR 9 is detected by the ACR 10
The ACR 10 outputs a control output so that the both agree with each other. The ACR 10 adds the control output to the field current controller 13 to adjust the field current of the generator.

It is assumed that the overcurrent detector 12 detects that the output current of the generator is overcurrent while the feedback control of the output current of the generator is performed in this way. If the output current feedback control is functioning normally, the generator output current should not be overcurrent.
This means that the feedback control of the output current is abnormal. Therefore, since the generator is broken as it is, the detection output of the overcurrent detector 12 instructs the ACR 10 to stop the operation of the generator to protect it. At the same time, the ammeter 17 is monitored and necessary measures are taken.

Next, the field current is detected by the field current detector 15, and the field current controller 13 is operated so that it becomes a predetermined value. When the control becomes abnormal, the overcurrent detector 14 may detect that the field current is overcurrent. Therefore, at that time, the field current controller 13 is notified that the overcurrent detector 14 has detected the overcurrent, and the operation of the generator is stopped to protect it.

[0008]

In FIG. 2, when the AC voltage detector 2 fails to detect the voltage and the voltage is no longer detected, the AVR 9 is controlled to increase the generator output voltage because the feedback voltage is lost. As a result, the generator output voltage becomes an overvoltage, but the overvoltage detector 11 also
Since the overvoltage cannot be detected due to the failure of the AC voltage detector 2, the generator could not be protected. In order to solve this, two AC voltage detectors 2 should be provided and used separately for feedback control and protection. However, by providing two AC voltage detectors 2, the cost is increased. Will occur.

Similarly, when the AC current detector 3 fails and no longer detects the current, the ACR 10 controls so as to increase the generator output current because the feedback current disappears, and as a result, the power generation is stopped. Although the machine output current becomes an overcurrent, the overcurrent detector 12 also cannot detect the overcurrent due to the failure of the AC current detector 3, so the generator cannot be protected. In order to solve this, two AC current detectors 3 should be provided and used separately for feedback control and protection. However, by providing two AC current detectors 3, the cost is increased. Will occur.

Further, when a failure occurs in the field current detector 15, even if the field current becomes an overcurrent, it cannot be detected, so that the protection operation by the field current controller 13 does not occur. was there.

The object of the present invention is to solve the above-mentioned problems of the prior art and to protect the generator when an abnormality occurs in the voltage feedback control or current feedback control of the generator without increasing the cost. It is an object of the present invention to provide a method of protecting a generator that can be carried out, and that even if a failure occurs in the field current detector, the protection operation is performed by the field current regulator.

[0012]

To achieve the above object, the present invention provides an AC generator which has a rectifier on its output side and which converts the generated AC power into a DC output by the rectifier and outputs the DC output. A voltage deviation detector that outputs an error voltage by comparing the average value of the armature voltage detection value and the detection value of the DC voltage that is the output of the rectifier, and the average value of the armature current detection value and the output of the rectifier. A current deviation detector that compares the detected value of the direct current and outputs an error current, and an overvoltage detector that detects the occurrence of overvoltage in the field winding are provided.

[0013]

In the above generator, the armature voltage is detected, and the regulated output is output by the automatic voltage regulator so that it becomes the predetermined voltage, and the field current is fed by the field current regulator to which it is input. When performing the voltage feedback control of controlling, if the error voltage from the voltage deviation detector exceeds a certain value, it is determined that an abnormality has occurred in the voltage feedback control, and the automatic voltage regulator is controlled. Protect the generator by shutting it down.

Further, in the above generator, the armature current is detected, and a regulated output is output by the automatic current regulator so that it becomes a predetermined current, and the field current regulator is input to the regulated output. If the error current from the current deviation detector exceeds a certain value while performing the current feedback control, it is determined that an abnormality has occurred in the current feedback control, and the current automatic regulator is controlled. To stop the generator and protect it.

Further, in the above generator, when the field current is feedback controlled by detecting the field current and controlling the field current by the field current regulator so that it does not become an overcurrent, The voltage drop due to the field current in the field winding is detected by the overvoltage detector, and when it detects the overvoltage (which means that the overcurrent has flowed in the field winding). Assuming that an abnormality has occurred in the magnetic current feedback control, the field current regulator is controlled to stop the operation of the generator to protect it.

[0016]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the same components as those in FIG. 2 are designated by the same reference numerals. In addition, 18 is a voltage deviation detector, 19 is a current deviation detector, and 20 is an overvoltage detector.

Referring to FIG. The voltage deviation detector 18 is
The average value of the generator armature voltage detected by the AC voltage detector 2 and the detected value of the DC voltage output from the rectifier 4 (DC voltage detector 5) are compared. For both voltages, the voltage drop due to the rectifier 4 is not so large, so normally,
The values should be almost the same. Therefore, when the error between the two voltages exceeds a certain value, it may be judged that the AC voltage detector 2 has failed, and as a result, the voltage feedback control does not work well. The output of the device 18 controls the AVR 9 to stop the operation of the generator.

Similarly, the current deviation detector 19 detects the average value of the generator armature current detected by the AC current detector 3 and the detected value of the DC current output from the rectifier 4 (DC current detector 6). Compare with. Both currents would normally have approximately the same value. Therefore, when the error between the two currents exceeds a certain value, it may be determined that the AC current detector 3 has failed and, as a result, the current feedback control has failed. Bowl 1
The output of 9 controls the ACR 10 to stop the operation of the generator.

The field winding 7 can be generally considered as a constant resistance load, and the magnitude of the field current flowing therethrough and the voltage (voltage drop due to the resistance load) generated thereby are substantially proportional to each other. Therefore, in FIG. 1, if the overvoltage detector 20 detects an overvoltage in a state in which the field current protector 13 does not function to protect the field current, it is determined that the field current detector 15 has failed. You can think.

That is, that the overvoltage detector 20 detects an overvoltage (an overvoltage of the voltage across the field winding 7) means that an overcurrent has flowed in the field winding 7, and naturally the field winding is Since the current detector 15 detects it and transmits it to the overcurrent detector 14, and the field current protection operation by the field current controller 13 may function, it means that it does not function. It is considered that the current detector 15 has failed.

At this time, the output of the overvoltage detector 20 controls the field current regulator 13 to stop the generator and protect it. When the field current detector 15 and the overcurrent detector 14 are functioning normally, the field current regulator 13 may be controlled accordingly, and the overvoltage detector 2
Since the output of 0 becomes an obstacle, the overcurrent detector 14 is locked to the overvoltage detector 20 so that the overvoltage detector 20 does not operate.

[0022]

As described above, according to the present invention,
Since it is not necessary to use two AC voltage detectors or current detectors for feedback control and protection, it is necessary to protect the generator when abnormalities occur in the voltage feedback control or current feedback control of the generator. There is an advantage that it can be performed without increasing the cost.

Further, even if a failure occurs in the field current detector, there is an advantage that the protection operation can be performed by the field current regulator to protect the generator.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a conventional generator protection method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Armature winding, 2 ... AC voltage detector, 3 ... AC current detector, 4 ... Rectifier, 5 ... DC voltage detector, 6 ... DC current detector, 7 ... Generator field winding, 8 ... Output voltage setting device, 9
... automatic voltage regulator (AVR), 10 ... automatic current regulator (ACR), 11 ... overvoltage detector, 12 ... overcurrent detector, 13 ... field current regulator, 14 ... overcurrent detector, 15
... field current detector, 16 ... voltmeter, 17 ... ammeter, 18
... Voltage deviation detector, 19 ... Current deviation detector, 20 ... Overvoltage detector

Claims (3)

[Claims] 1. An alternating current generator having a rectifier on its output side, which converts the generated alternating current power into a direct current output by the rectifier and outputs the direct current output, detects an armature voltage, and makes it a predetermined voltage. , The average of the detected armature voltage when performing voltage feedback control, in which a field current controller controls the field current by outputting a control output by the automatic voltage controller The value is compared with the detected value of the DC voltage which is the output of the rectifier, and if the error therebetween exceeds a certain value, it is determined that an abnormality has occurred in the voltage feedback control, and the automatic voltage regulator is controlled to generate electricity. A method for protecting a generator, which comprises stopping the operation of the machine to protect it. 2. An AC generator which has a rectifier on its output side and which converts the generated AC power into a DC output by the rectifier and outputs the DC power, detects an armature current, and makes it a predetermined current. , The average of the detected armature currents when performing the current feedback control, in which the automatic current regulator outputs the regulated output, and the field current regulator that receives the regulated output controls the field current. The value is compared with the detected value of the DC current that is the output of the rectifier, and if the error therebetween exceeds a certain value, it is determined that an abnormality has occurred in the current feedback control, and the automatic current regulator is controlled to generate electricity. A method for protecting a generator, which comprises stopping the operation of the machine to protect it. 3. An AC generator which has a rectifier on its output side and which converts the generated AC power into a DC output by the rectifier and outputs the DC power, detects a field current, and prevents it from becoming an overcurrent. When performing the field current feedback control that controls the field current with the field current regulator, the voltage drop due to the field current in the field winding is detected as a voltage and it becomes an overvoltage. At this time, it is assumed that an abnormality has occurred in the field current feedback control, and the field current regulator is controlled to stop the operation of the generator to protect the generator.