JPH0246200A - Operation control of synchronous machine - Google Patents

Abstract

PURPOSE:To prevent an electric equipment from being damaged by over-. excitation by performing gate interruption of an excitation device by the output signal of an overexciting relay and that of a field circuit breaker trip incapability detection device. CONSTITUTION:When a generator 17 is stopped, a parallel circuit breaker 11 is opened in unloaded condition, and then a field circuit breaker is cut off. At this moment, the generator 17 is parallelled off from a system 11A. However, when a field circuit breaker 18 comes to be unable to trip, a main machine rotating speed 23 is reduced. Since an automatic voltage regulator 13 acts on so as to keep generator voltage 24 at a rated value 22 and corrects the reduced portion of voltage instantaneously, it causes excessive exciting current 25 to flow. An overexciting relay 16 inputs an AND signal of an operation signal and an output signal of a field circuit breaker trip incapability detection device 18A is inputted into the automatic voltage regulator 13 and performs gate interruption of an exciting rectifier 19. Abnormal rise of V/F value of the generator in the stopping control can thereby be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for controlling the operation of main equipment such as a generator, a main transformer, and an in-house transformer in a hydroelectric power plant.

(Prior art) When starting a generator at a hydroelectric power plant, excitation is applied at about 80% of the generator's rated voltage as shown in Figure 3, and the generator voltage phase is 9.
When the frequency matches the system bus voltage 2-phase 9-frequency, normal start-up control is performed so that the system is parallel to the system. As shown in Fig. 4, if the generator voltage drops due to a grid failure after the generator 17 is paralleled to the grid bus 11A, the ratio between the generator voltage and the frequency will change because the generator 17 is rotating at the rated speed. The voltage/frequency (hereinafter referred to as V/F) value expressed by becomes higher.

Alternatively, during stop control, the trip coil (not shown) of the field breaker 18 is disconnected and cannot be tripped, and when the generator voltage is constant and the frequency decreases, the V/F value increases. When this V/F value becomes high, the generator 17 becomes overexcited and overheats.

The cause of this overheating is that saturation of magnetic flux due to V/filtration excitation occurs in the core, which is a magnetic circuit. This occurs due to current overheating. This result V
If the /F value becomes high, the generator 17 will overheat and may even be damaged.

In order to avoid this damage, conventionally, the generator voltage is monitored by a voltage relay 41, a voltage value is set in advance, and a seed circuit is configured to stop the generator 17 when the voltage value exceeds the set value.

That is, as shown in FIG. 2, the main engine maintains its rated value up to the grid disconnection point 31, but in this case, when the breaker is released, the generator is disconnected from the grid and the main engine rotational speed 23 decreases.

At the same time, the field breaker is released and the excitation circuit is also disconnected. However, if the field breaker is not released for some reason, the automatic voltage regulator works to maintain the generator voltage 34 at the rated value, and in order to instantly compensate for the drop in voltage, excessive excitation current may be generated. 25, which is said to be 4 to 5 times the rated value.On the other hand, as the main engine rotational speed 23 decreases, the V/F value 26 increases. As a result, the main equipment of the power plant, such as the generator and main transformer, is placed in an overexcited state and the temperature rises.
There was a problem of insulation deterioration.

(Problem to be solved by the invention) As described in the conventional technology, overheating of the main engine due to the V/F value ratio occurs when the ratio between the generator voltage and the rotation speed (frequency) of the generator exceeds the allowable value. Occurs when exceeded. - For boat fishing, generators are operated so that the ratio of voltage and rotational speed does not exceed the permissible value.

Therefore, the fundamental problem is to change the voltage 2 rotations value to V/F.
There is a problem in that the operation control of the main engine must be performed based on the ratio of

The voltage/frequency ratio of major equipment such as generators and main transformers of a hydroelectric power plant is increased to prevent damage to the necessary equipment of the power plant due to overheating.

[Structure of the invention]

(Means for solving problems) In order to achieve the above-mentioned purpose, explanation will be given using drawings.

FIG. 1 is a diagram showing an embodiment of the present invention. That is, the parallel circuit breaker 11 connected in parallel to the system bus lIA
, the main transformer 1 connected in series with the parallel breaker 11
4, and a generator 17 connected in series with the main transformer 14. On the other hand, automatic voltage regulator 13 for excitation device
is connected via the excitation transformer 12 and connected to the gate circuit of the excitation rectifier 19. Overexcitation relay 16
is connected to the main bus through a protective relay transformer 15.

The field winding of the generator 17 is connected to the excitation rectifier 19 via the field breaker 18.
A field breaker tripping failure detection device 18A for detecting a tripping failure state of the field breaker 18 is connected to the field breaker 18.

(Operation) When stopping the generator 17, the output of the generator 17 is reduced, the parallel breaker 11 is opened with no load, and then the field breaker 18 is disconnected to stop the generator 17. In the case of an emergency stop, the parallel breaker 11 is released and the field breaker 18 is also released to disconnect the excitation circuit from the generator 1.
7 is normally controlled to stop. In order to detect the non-trip state of the field breaker 18, the field breaker 18 is monitored by the field breaker non-trip detection device 18A, and the field breaker 18 detects any cause such as disconnection of the trip coil (not shown). In other words, as shown in the second @, the main engine rated value is maintained until the grid disconnection point 21, but the generator 17 is disconnected from the grid 11A, but the field breaker 18
When the main engine rotation speed 23 becomes non-trippable, the main engine rotational speed 23 decreases. However, the automatic voltage regulator 13 works to maintain the generator voltage 24 at the rated value 22 and instantaneously supplies an excessive excitation current 25 to compensate for the drop in voltage, while the main engine rotational speed 23 decreases. Therefore, the V/F value 26 increases. At this time, the overexcitation relay 16 exceeds the set value and the overexcitation relay 16 operates. At this time, the AND signal of the output signal and the output signal of the field breaker trip failure detection device 18A is input to the automatic voltage regulator 13, and the gate is cut off to cut off the excitation current and the generator V/F in the stop control. Control can be performed to prevent abnormal increases in values and safely stop the generator.

Although the above example was explained using a generator, protective control can be performed in the same way even when the generator motor (synchronous motor) is operating in conjunction with the grid.

After the generator-generator is connected in parallel to the system bus, if the rotation speed of the generator-generator decreases due to input loss, etc. When the V/F value exceeds the preset value by the overexcitation relay, the overexcitation relay and the output signal of the field breaker trip failure detection device.

The generator motor can be safely stopped by shutting off the gate of the excitation device via an automatic voltage regulator, cutting off the excitation current, and reducing the excitation current of the generator.

〔Effect of the invention〕

As described above, according to the present invention, the generator or generator motive
If a voltage drop occurs due to input loss or grid failure during operation,
When an emergency stop operation is performed on the main engine, in the event that the main engine stops due to failure due to breakage of the trip coil of the field breaker, etc., the electrical equipment is controlled so that the voltage 9 frequency ratio is kept below a certain value. Damage caused by overexcitation can be prevented and the life of the equipment can be extended.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is a time chart explaining the operation when stopped, Fig. 3 is a time chart when the grid is parallel, and Fig. 4 is a schematic diagram of the generator operation control device. It is a diagram. 11... Parallel circuit breaker 11A... System bus 12
...' Excitation transformer 13... Automatic voltage regulator 14... Main transformer 15... Protective relay transformer 16... Overexcitation relay 17... Generator generator 18
...Field breaker 18A...Field breaker trip failure detection device 19
...Excitation rectifier 21...System disconnection point 22...
・Main engine rated value 23... Main engine rotation speed 24... Generator voltage 25... Exciting current 26... Voltage/frequency ratio 31... Voltage characteristic curve 32... Rotation speed characteristic curve 41...・Voltage relay agent Patent attorney Norihiro Ken Yudo Daishimaru Ken System bus line Figure 2 Figure 1 Figure System bus line diagram

Claims (1)

[Claims] In a hydroelectric power plant with a synchronous machine, the system bus, the parallel line disconnector, the main transformer, the generator, the field liner, the automatic voltage regulator for the exciter, the overexcitation detector, and the field liner are used. The overexcitation detection device monitors the voltage/frequency ratio of the main transformer and generator when the field is turned off or the breaker becomes unable to trip.
A synchronous machine characterized in that when a preset value is exceeded, the thyristor gate of the excitation device is cut off by the output signal of the overexcitation detection device to protect the generator and the main transformer from damage. Operation control method.