JPS63133900A - Excitation controller for synchronous machine - Google Patents

Abstract

PURPOSE:To stably operate to a synchronous machine even at the time of defective machine by providing a low excitation protecting device for removing an AVR when the defect of a signal mixer, an overexcitation state and a low exciting state are detected. CONSTITUTION:A deviation between the terminal voltage of a synchronous generator 1 and a reference voltage is input to a signal mixer 53. A magnetic increasing signal is input from a low excitation limiter 5 and a magnetic decreas ing signal is input from an overexcitation limiter 8 to the mixer 53. A field tracking unit 56 so adjusts a base setter 55 that the output of the mixer 53 is always zero. An AVR automatic/removing switching contact 54 is opened by a low excitation protecting device 10 under the conditions that the output of the mixer 53 becomes a magnetic reduction signal of a certain value or more, a deviation between the output of the mixer 53 and the output of a monitoring signal mixer 153 becomes a certain value or more, an overexcitation limiter 8 outputs a magnetic decreasing signal, and a low excitation limiter 6 outputs a magnetic increasing signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low excitation protection device in an excitation control device for a synchronous machine.

[Conventional technology]

FIG. 8 is a configuration diagram of a conventional general excitation system equipped with an overexcitation control device and an underexcitation limiting device, as shown in, for example, Japanese Patent Application Laid-open No. 56-15196 and Japanese Patent Application Laid-Open No. 58-17600θ. In the figure, (1) is a synchronous generator, (
2) is the field winding, (3) is an excitation device that supplies the amount of excitation of the field winding (2), and (4) is the synchronous generator (1).
), a voltage detection unit that detects the terminal voltage (output voltage) of (5
) compares the output of the voltage detection section (4) with a reference voltage using an automatic voltage regulator M (hereinafter referred to as AVR) for adjusting the terminal voltage of the synchronous generator (1), and calculates the deviation. The excitation device (3) is controlled accordingly. (6) is a low excitation limiting device that detects the low excitation region of the generator from the terminal voltage, output current, and phase of the synchronous generator (1), and provides the signal to A V Rf5) as a low excitation limiting signal. It is something. (7) is a current shunt for detecting the field current flowing through the field winding (2). (8) is an overexcitation limiting device that detects the overexcitation region of the generator from the field current detected by the shunt (7) and provides the signal to A VR (s) as an overexcitation limiting signal. It is.

The AVR (5) includes a reference section (2) that generates a reference voltage that is a target value of the terminal voltage of the synchronous generator (1), and an amplifier (A) that amplifies the deviation between the reference voltage and the terminal voltage. , a signal mixer stirrup that adds the output of the amplifier A (52, the output of the low excitation limiter (6), and the output of the overexcitation limiter (6) at an appropriate level, A V Rf5); AVR automatic/exclusion switching contact-1 which closes when automatic operation is to be performed and closed during exclusion operation.When automatic operation is performed, the AVR automatic/exclusion switching contact-1 AVR (5) is kept at the same pace as the amount of excitation flowing to the field winding (2) above. When operating A VR(s) in an exclusive manner, the base setting device pressure is used as a manual excitation amount setting device, and the base setting is set according to the output of the signal mixing device to always keep the output of the signal mixing device at zero. Adds the output of the base setting device (50) and the output of the AVR automatic/exclusion switching contact diagram, further increases the width, and controls the excitation device (3). Amplifying part B 05 that outputs a signal to
71 etc. as the main components.

Next, the operation will be explained. Now, if the terminal voltage of the synchronous generator (1) fluctuates due to a disturbance while the synchronous generator (1) is in operation, the terminal voltage of the synchronous generator (1) detected by the voltage detection section (4) will change at the AVR (5). It is compared with the reference voltage from the reference section 15Il, and its deviation is determined by the amplifying section A f+s5, the signal mixing section, the AVR automatic/exclusion switching contact diagram, and the amplifying section B.
m7) and is amplified to an appropriate level. The excitation device (3) adjusts the field current of the field winding (2) according to the output control signal of this amplifier B f571, and controls the synchronous generator (1).
) is controlled. This series of control operations is continuously performed until the deviation between the reference voltage and the terminal voltage becomes equal to or less than a predetermined value, and the terminal voltage of the synchronous generator (1) is maintained at the target value. Furthermore, when the reactive power of the synchronous generator (1) during load operation becomes small (or on the leading side), the low excitation limiting device 6) issues a magnetization signal. This low excitation control device (6
) becomes a signal on the magnetizing side compared to the signal from the amplifying section Af52, the signal from the low excitation limiting device (6) is prioritized in the signal mixing unit and low excitation is limited. Further, when the field current flowing through the field winding (2) of the synchronous generator (1) exceeds a permissible value, the overexcitation limiting device (8) issues a demagnetization signal. The signal from this overexcitation limiting device (6) is added to the output of the normal demagnetizing section A in the signal mixing unit, thereby limiting overexcitation. Since the permissible value of the field current normally has a time limit characteristic, the overexcitation limiting device (8) also normally has a similar time limit characteristic. Also, in the normal signal mixing section, the overexcitation limiting device (8) is higher than the low excitation limiting device (6).

These overexcitation limiting device (8) and low excitation limiting device 46
1K, if the width increaser A (52) fails and, for example, the output of the width increaser AJZ becomes equal to the number of magnetization signal peaks, the overexcitation limiting device (8) will control the width increaser 152. When the output reaches the number of demagnetization signal peaks, a low excitation limiting device (6) is used to ensure stable operation.

[Problem that the invention seeks to solve]

Conventional excitation control devices are configured as described above, so even if the signal mixer or overexcitation limiter fails and the number of demagnetization signal peaks decreases, the low excitation limiter will not work (signal mixer (If the synchronous generator is in a low excitation state, the synchronous generator is in a low excitation state and the synchronous generator is out of synch.) There was a problem with this.

This invention was made to solve the above problems, and even if the signal mixing unit or overexcitation limiting device fails and the number of demagnetization signal peaks decreases, the synchronous generator remains in a low excitation state. An object of the present invention is to obtain an excitation control device incorporating a low excitation protection device that can prevent synchronization and step-out.

[Failure to solve the problem]

The low excitation protection device according to the present invention detects a failure in the signal mixing unit or the overexcitation limiting device, and synchronizes the AVR by switching the AVR from automatic operation to excluded operation when the operating state of the synchronous generator becomes a low excitation state. This is designed to provide low excitation protection for the generator.

[Function] The low excitation protection device of the present invention detects the low excitation state of the synchronous generator, thereby switching the AVR from automatic operation to excluded operation, thereby preventing tax adjustment of the synchronous generator.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (15B) is a monitoring signal mixing section, which, like the signal mixing section i5s, receives the output of the widening section A (5B, the output of the low excitation limiter (6), and the output of the overexcitation limiter (8)). (1 (l) is the low excitation protection device, and the respective appearance of the signal mixing unit, monitoring signal mixing unit (158), low excitation limiting device (6), and overexcitation limiting device (8) has been changed for a long time. When a low excitation state is detected, the AVR automatic/exclusion switching contact □□□ is opened. Fig. 2 shows the internal logic diagram of the low excitation protection device Q (I). In Fig. 2, (101) Each input terminal (102) is a comparator A that detects that the output between the signal mixing sections has become a demagnetized signal exceeding a certain value.(108) is a comparator B that detects the output of the signal mixing section. It is detected that the deviation between the output of the monitor signal mixer (158) and the output of the monitoring signal mixer (158) exceeds a certain value.

(104) detects with a comparator that the overexcitation limiting device (8) is outputting a demagnetization signal. (105) is a comparator which detects that the low excitation limiting device (6) is outputting a magnetizing signal. (106) is a comparator A-D (102-1
The timer (107) provided at the output of 05) opens the low excitation protection device Q (AVR automatic/exclusion switching contact paulownia at the output terminal of 1).

Next, the operation will be explained. Now, assuming that there is a failure between the signal mixers and the demagnetization signal peaks, the output of comparator A (102) is 'ON' and the output of comparator B (108) is The output is also related to the signal mixing section, so
It becomes ON'. On the other hand, the field winding (2) of the synchronous generator (+,)
) The field current flowing through the synchronous generator (
The operating state of 1) becomes a low excitation state, and the low excitation limiter (
6), and the output of the low excitation limiting device (6) outputs a magnetizing signal. As a result, the output of the comparator D (105) becomes 1ON1, and when the timer (106) completes its operation, an AVR exclusion command is generated from the output terminal (107) of the low excitation protection device 00, and the AVR automatic/exclusion switching single-point circuit is released. be done. As a result, the demagnetizing signal that has been output from the signal mixing section is disconnected, and the field current flowing through the field winding (2) returns to its original value. Overexcitation limiter (8)
Even if the synchronous generator (1) fails and the number of demagnetization signal peaks decreases, the synchronous generator (1) will generate the same @operation as described above, and as a result, the synchronous generator (1) will not go into a low excitation state, and step-out can be prevented.

In the above embodiment, the comparators for the outputs of the overexcitation limiting device (8) and the low excitation limiting device (6) were provided in the low excitation protection device Qd, but the overexcitation limiting device (8) and the low excitation limiting device ( 6) may be provided within. Further, although a monitoring signal mixing section (158) is provided for monitoring between the signal mixing sections, depending on hardware considerations, the monitoring section may include the amplification section AI2% standard υ, etc.

In addition, although the above embodiment explained the case of a Fi synchronous generator,
A synchronous motor may be used, and the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, failure of the signal mixing section, overexcitation state, and underexcitation state are detected in the excitation limiting device, and the AV
Since a low excitation protection device excluding R is provided, the synchronous generator can operate stably without stepping out even when the device fails.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an excitation system equipped with a low excitation protection device according to an embodiment of the present invention, Fig. 2 is a block diagram showing the operation of the low excitation protection device, and Fig. 3 is a block diagram of a conventional excitation system. shows. (5) is the AVR-scold signal mixing unit, (158) is the monitoring signal mixing unit, (6) is the low excitation limiter, (8) is the overexcitation limiter, aO is the low excitation protection device, and is the AVR Shows automatic/exclusion switching contact. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In the excitation control device of a synchronous machine, when a failure of the signal mixing unit or overexcitation limiting device is detected and the operating state of the synchronous machine becomes a low excitation state, the automatic voltage regulator is switched from automatic operation to exclusion operation. Excitation control device for synchronous machine with low excitation protection device.