JPS6355297B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic parallel disconnection device during parallel operation in a motor generator with an electromagnetic coupling.

Conventionally, a configuration shown in FIG. 1 has been known as an automatic disconnection device for a failed machine during parallel operation of this type of motor generator with an electromagnetic coupling. In FIG. 1, 1 is a driving power source for a motor generator, 2 is a wiring cutter inserted into the driving power source 1,
3 is an electromagnetic contactor for switching the power supply of the electric motor 5, which will be described later;
4 is a thermal relay for protection of the electric motor 5; 5 is a driving electric motor for the generator 7; 6 is an electromagnetic coupling for frequency control of the generator 7; 6a is a field coil of the electromagnetic coupling 6; 7 is a generator; 7a is a The field coil of the generator 7, 9 is an automatic frequency regulator (AFC) connected to the field power transformer 8, and 10 is an automatic voltage regulator (AVR) connected to the field power transformer 8. , 11 is a field current detector of the electromagnetic coupling 6, which operates the overcurrent relay 12 to open and close the normally open contact 12a of the overcurrent relay 12. Reference numeral 13 denotes a field current detector of the generator 7, which activates the overcurrent relay 14 to detect the overcurrent relay 1.
The normally open contact 14a of No. 4 is opened and closed. Reference numeral 15 denotes a load switch or disconnector, 15a an operating circuit for the load switch or disconnector 15, 16 a power supply bus, and 17 a motor generator with an electromagnetic coupling.

The circuit operation of the conventional device having such a configuration will be described below. First, the motor generator 17 with an electromagnetic coupling is used as a power source for a large computer, and is used by converting the voltage and frequency in order to improve the quality of the power source 1, that is, voltage stability and noiselessness. In this case, automatic frequency regulator (AFC) is used to control the frequency of the generator bus 16.
9 controls the current flowing through the field coil 6a of the electromagnetic coupling 6 to change the rotational speed of the generator 7. The voltage of the generator bus 16 is determined by controlling the current flowing through the field coil 7a of the generator 7 by an automatic voltage regulator (AVR) 10.

The protection devices for the motor generator 17 with electromagnetic coupling include a wiring shield and disconnector 2 for cable protection, a thermal relay 4 for protecting the motor, an air shield and disconnector 15 for protecting the generator and cables, and the automatic frequency adjustment. A current detector 1 is installed in each field coil 6a, 7a for field current caused by failure of the device (AFC) 9, automatic voltage regulator (AVR) 10, etc.
1, 13 and overcurrent relays 12, 14 are inserted, and when a field overcurrent occurs, these normally open auxiliary contacts 12a and 14a are closed to excite the trip coil of the air cutter 15 and turn on the power supply. It is made to trip more than 16.

However, since the conventional automatic parallel disconnection device for parallel operation of motor generators was configured as described above,
For example, if a failure occurs in which the induced voltage of the generator decreases due to field loss in a generator during parallel operation, other healthy generators will also try to quickly recover from the drop in bus voltage, causing the field to drop. A mis-trip occurred due to magnetic overcurrent. Similarly, in the event of an accident in which the field of the electromagnetic coupling is lost during parallel operation, even the healthy machine will overcurrent and mistrip in order to compensate for the drop in the bus frequency, resulting in a drawback.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology.It automatically determines the magnitude of the generator field current in response to bus voltage abnormalities during parallel operation, and also prevents bus frequency abnormalities. For,
It is an object of the present invention to provide a parallel operation automatic disconnection device for motor generators that can automatically identify a failed machine based on the magnitude of field current of an electromagnetic coupling and automatically disconnect it from the grid.

An example of the present invention will be explained below with reference to the drawings. In FIG. 2, the same parts as in FIG. 1 are designated by the same reference numerals. In FIG. A comparator for comparison, 20 a frequency detector for detecting frequency abnormality of the generator bus, 2
1 is a voltage detector for detecting voltage abnormality of the generator bus; 22 is a faulty machine discrimination circuit that compares the magnitude of the field current of the electromagnetic coupling in response to a frequency abnormality of the generator bus to determine a faulty machine; 23 is a generator A faulty machine discrimination circuit 24 compares the magnitude of the generator field current due to an abnormal bus voltage and discriminates the faulty machine. This is an automatic disconnection circuit that trips the disconnector.

The operation of the present invention configured in this manner will be described below. The following two cases can be considered as the abnormal phenomenon of the generator power supply. The first is a failure in the generator system that appears as some abnormality in the induced voltage of the generator, and the second is a failure in the drive side, such as an electromagnetic coupling system, that appears as an abnormality in the number of revolutions and frequency. Furthermore, the generator output voltage and field current, as well as the generator frequency, for example, the number of rotations, and the field current of the electromagnetic coupling are approximately proportional to each other. Therefore, if an abnormality occurs in the output voltage and output frequency during parallel operation, the field current of the electromagnetic coupling will also change for the reasons mentioned above. For example automatic voltage regulator (AVR)
When the generator output voltage becomes overvoltage due to a failure such as 10, the voltage detector 21 detects that the bus voltage has become overvoltage, and the comparator 19 compares the magnitude of the generator field current. The faulty machine identification circuit 23 clearly identifies the larger one as the faulty machine, and the automatic parallel disconnection circuit 24 detects an air leak or disconnection 1 on the faulty machine side.
5 are interlocked to trip and disconnected from the system.
Similarly, in the case of a failure in which the output voltage of the generator decreases, the faulty machine can be determined by comparing the result of the field current comparator 19 in the generator with the abnormality of the bus voltage based on the magnitude of the field current. The automatic parallel disconnection circuit 24 determines that the one with the smaller field current is the faulty machine using the circuit 23, etc., and trips the air leak or disconnection switch 15 on the faulty machine side among the generators operating in parallel to disconnect the system. Make it more disorganized. Similarly, in the case of frequency abnormality, the frequency abnormality is detected by the bus frequency detector 20, and then the faulty machine is detected from both the input signals of the frequency abnormality result and the magnetic current comparator 18 of the electromagnetic coupling. The judgment is made by the discrimination circuit 22, and when the bus frequency decreases, the one with the smaller field current of the electromagnetic coupling is determined to be the failed machine, and when the bus frequency increases, the one with the larger field current is regarded as the failed machine, and automatic An output signal is transmitted to the disconnection circuit 24 to trip the air disconnector 15 on the faulty machine side and disconnect the system from the system.

As described above, according to the present invention, the magnitude of the field current of the electromagnetic coupling is compared based on changes in the output voltage and abnormalities in the output frequency of the generator during parallel operation, and a faulty machine is identified and the faulty machine is removed. Since automatic paralleling is performed, there is a remarkable effect that an automatic paralleling device can be provided at a low cost during parallel operation of a motor generator with an electromagnetic coupling, which has a simple circuit configuration, high stability, and high reliability.

[Brief explanation of drawings]

Fig. 1 is a block configuration diagram showing a conventional protection device for a motor generator, and Fig. 2 shows an automatic parallel disconnection device for a failed machine during parallel operation of a motor generator with an electromagnetic coupling according to an embodiment of the present invention. FIG. 3 is a block configuration diagram. 11, 13... Current detector, 18, 19... Comparator, 20... Frequency detector, 21... Voltage detector, 2
2, 23...Failure machine determination circuit, 24...Automatic disconnection circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. In a faulty machine automatic disconnection device that automatically identifies and automatically disconnects a faulty machine due to a fault accompanied by voltage or frequency abnormality in the power generation system of either one of the motor generators with electromagnetic coupling that are running in parallel, a bus bar abnormal voltage detector and a bus bar frequency abnormality detector for detecting that the voltage and frequency of the power supply bus bar are abnormal; A field current comparator of the electromagnetic coupling and a field current comparator of the generator that compare both field currents respectively, and a field current comparator of the generator and the electromagnetic coupling that compares the field current of the generator and the electromagnetic coupling due to an abnormality in the voltage of the bus bar or the frequency of the bus bar during the parallel operation. An electromagnetic coupling failure determination circuit and a generator field current failure determination circuit that compare magnetic currents and determine a faulty machine;
A parallel operation automatic parallel disconnection device for a motor generator, comprising: an automatic parallel disconnection circuit that receives output signals from the two sets of failure determination circuits and disconnects a failed machine from the system.