JPH03138462A - Control for speed governing - Google Patents

Abstract

PURPOSE:To surely detect a trouble even in the case where a speed signal generator is used for detecting the speed of a power generator, by comparing the power generator frequency and power generator speed, judging the generation of trouble when the speed difference becomes over a prescribed value and generating a main machine stop signal. CONSTITUTION:When a waterwheel starts and a speed signal is generated from a speed signal generator 11, the speed governing control part in an integrally formed controller 14 converts the speed signal to the power generator speed 20. Further, when the revolution speed of the waterwheel increases and reaches about 70-80%, excitation is applied by the excitation control past of the integrally formed controller 14, and a voltage is generated in a power generator 1, and at this time, the power generator voltage is F/V-converted in a synchronous control part, and the power generator frequency 19 is detected and used for the synchronous control. In a comparing part 21, the power generator frequency 19 and the power generator speed 20 are compared, and the speed difference 22 is detected, and judgement part 23 judges if the speed difference 22 is within a prescribed value 25 or not. In the case of failure where the result of the judgement is 'NO', a main machine stop signal is generated.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention compares the frequency of a generator and the speed signal of a speed signal generator, and detects whether the speed signal generator is malfunctioning or has a circuit break. This invention relates to a speed governing control method for an integrated control device that can quickly and safely stop the main engine when the speed signal disappears due to a short circuit or the like.

(Prior art) Generally, when the speed detection method of the generator is a permanent magnet generator, the speed signal from the permanent magnet generator disappears during operation due to a failure of the permanent magnet generator or a circuit disconnection or short circuit. When this occurs, an undervoltage relay detects this voltage drop in the speed signal and issues a stop command. A conventional speed governor control device will be explained below. FIG. 4 shows a control circuit configuration of a conventional speed governor control device. 1 is a generator, 2 is a breaker for paralleling and disconnecting from the grid, 3 is a permanent magnet generator that generates a speed signal, 4 is a rectifier that rectifies the speed signal, 5
is a speed relay that detects the frequency of the generator 1; 6 is a tachometer that displays the frequency of the generator 1; 7 is a speed governor control device 10
8 is a speed detection transformer that supplies a speed signal to the speed governor control device.

The operating procedure of the governor control device will be explained below with reference to FIG. First, the water wheel (not shown) starts and the rotation speed reaches 70.
When the voltage reaches ~80%, the undervoltage relay 9 is restored and the governor control device 10 is activated. The speed governor control device 10 is
Adjust the rotation speed of the water wheel to the specified value. Then, it enters the grid in parallel through the parallel breaker 2 and enters the operating state. Thereafter, if the permanent magnet generator 3 breaks down or a malfunction such as a disconnection or short circuit occurs in the circuit, the speed signal from the permanent magnet generator 3 disappears.

For this reason, the power supply and speed signal of the speed governor control device 10 are lost and control becomes impossible, so the undervoltage relay 9 detects a drop in the power supply voltage of the speed governor control device 0 and issues a stop signal.

(Problems to be Solved by the Invention) As described above, when the speed detection method of the generator is a permanent magnet generator, malfunctions such as failure of the permanent magnet generator 3 or circuit breakage or short circuit may occur during operation. However, the undervoltage relay 9 can detect this malfunction and stop the operation quickly and safely. However, permanent magnet generators are very expensive, and recently, because precision is required, the speed detection method has been changed from permanent magnet generators to speed signal generators. If the speed detection method is a speed signal generator, the power to the speed governor control device is supplied from the power supply device, so if a similar problem occurs, the speed governor control device remains alive and only the speed signal is output. It will disappear. For this reason, the governor control device tries to reduce the speed, but since it is parallel to the system, the speed does not increase and the load increases, which may cause overload operation to continue.

Therefore, an object of the present invention is to prevent the speed signal generator from failing or breaking the circuit during operation, even when the speed signal generator is used as the speed detection method of the generator, as in the case of using a permanent magnet generator. To provide a control method that can quickly and safely stop a main engine even if a malfunction such as a short circuit occurs.

[Structure of the Invention] (Means for Solving the Problem) The present invention constantly compares the generator frequency and the generator speed, and detects failure of the speed signal generator, disconnection of the circuit, short circuit, etc. during operation. When a problem occurs, the speed deviation between the generator frequency and the generator speed increases, so a stop command is issued when this speed deviation is larger than a specified value.

(Function) Therefore, even if the speed signal is lost due to a failure of the speed signal generator or a malfunction such as disconnection or short circuit of the circuit while the generator is in operation, the main engine can be stopped quickly and safely.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 shows an integrated control device according to one embodiment of the invention. In this figure, the same or corresponding parts as in FIG. 3 are designated by the same reference numerals, and the explanation thereof will be omitted. In the figure, 11 is a speed signal generator for speed governor, 12 is a speed signal generator for speed relay, 13 is a transformer for a synchronizer that supplies generator voltage, and 14 is a sequence control.

My-4 = common speed governor control, excitation control, and secondary adjustment control This is an integrated control device that processes using a microprocessor.

The integrated control device 14 performs speed regulating control by performing the processing shown in FIG.

In FIG. 1, a comparison section 2 is a comparison section 23 that compares a generator frequency 18 and a generator speed 20 to calculate a speed deviation 22;
is a determination unit that determines whether or not the speed deviation is within the specified speed deviation value 25, and outputs a stop command 24 if the speed deviation is greater than or equal to the specified speed deviation value 25.

First, when a water turbine (not shown) is started, a speed signal is generated from a speed signal generator. The governor control unit in the integrated control device 14 converts the speed signal from the governor control speed signal generator 11 into a generator speed 20, and uses it for governor control. Then, when the rotation speed of the water turbine increases and reaches 70 to 80%, excitation is applied by the excitation control section of the integrated control device 14, and a voltage is generated in the generator 1. At this time, the synchronous control section in the integrated control device 14 performs F/V conversion on the generator voltage, detects the generator frequency 19, and uses it for synchronous control.

The comparing section 21 compares the generator frequency 19 and the generator speed 20 to calculate a speed deviation 22, and the determining section 23 determines whether or not this speed deviation 22 is within a specified speed deviation value 25. If the speed deviation 22 is within the specified speed deviation value 25, the determination unit 23 does not operate, but the speed control speed signal generator 11
If a failure or a circuit breakage, short circuit, etc. occur, the generator speed 20 will be lost, and the speed deviation 22 will increase and become equal to or higher than the specified speed deviation value 25. The determination unit 23 determines the speed deviation 22
detects that the speed deviation exceeds the specified speed deviation value of 25 and issues a command to stop the main engine.

As described above, even if a problem such as a failure of the speed signal generator or a circuit disconnection or short circuit occurs during operation, the main engine can be stopped quickly and safely. In the case of an integrated control device, the generator frequency is a signal for synchronous control, and the generator speed is a signal for conventional speed governor control, so there is no need to install a new converter, which is a big advantage. .

Up until now, we have focused on cases in which the speed signal is lost due to a failure in the speed signal generator or due to a disconnection or short circuit in the circuit, but conversely, when the speed signal generator and circuit are normal, power generation may occur due to a failure in the excitation device, etc. The same effect can be obtained even if the machine voltage is lost.

However, in this case, other protection circuits will detect it first.

Although the present invention detects a failure of the speed signal generator, a circuit break, a short circuit, etc. by comparing the generator frequency and the generator speed, it is also possible to detect a failure, a circuit break, a short circuit, etc. by comparing the generator speed and a reference frequency setting value. FIG. 3 shows the processing method.

First, the comparison unit 21 is
The generator speed 20 is compared with the reference frequency setting 26, and a speed deviation 22 is calculated. The determination unit 23 determines whether the speed deviation 22 is within the specified speed deviation value 25, does not operate if it is within the specified speed deviation value 25, and issues a stop command when the speed deviation specified value is 25 or more. This method is applicable not only to integrated control devices but also to general governor control devices.

〔Effect of the invention〕

As described above, by using the speed governor control method to which the present invention is applied, even if the speed detection method of the generator uses a speed signal generator, the speed signal generator may fail during operation, or the circuit may be disconnected or short-circuited. Even if such a malfunction occurs, the main engine can be stopped quickly and safely without overloading.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the speed governing control method of the present invention, FIG. 2 is a configuration diagram of a device to which the present invention is applied, FIG. 3 is a block diagram showing another embodiment, and FIG. 4 FIG. 1 is a configuration diagram showing a conventional speed governor control method. 1... Generator 2... Parallel breaker 3.
... Permanent magnet generator 4 ... Rectifier 5 ... Speed relay 6 ... Tachometer 7 ... Power transformer
8... Speed detection transformer 9... Undervoltage relay
10... Speed governor control device 11... Speed signal generator for speed governor

Claims (1)

[Claims] In an integrated control device that processes sequence control, speed governing control, excitation control, and secondary regulation control in a hydroelectric power plant using a common microprocessor, the generator frequency of the generator voltage and the generator speed signal from the speed signal generator are used. and a determination section that determines whether the speed deviation, which is the output of the comparison section, is within a specified speed deviation value, and the generator frequency and the generator speed, which are the outputs of the comparison section. If the speed deviation of the signal is within a specified speed deviation value, the judgment section does not operate, and when the speed deviation is above the specified speed deviation value, the judgment section issues a stop command to stop the main engine. Speed regulating control method for control device.