KR20010028872A - The method of electrical overspeed protection and speed signal generation for speed control of prime movers for electric power generation - Google Patents

Abstract

PURPOSE: A method of generating a signal for preventing overspeed and controlling the speed of a generating motor is provided to electrically protect the motor from dangerous situations to guarantee stable operation and secure reliability of speed signal required for starting, normal operation and stopping procedures of the motor. CONSTITUTION: A pulse signal generated by a speed signal detector for detecting the speed of a motor is divided to be applied to three intermediate value selection electronic cards(101,101a,101b) capable of selecting the intermediate value of the pulse signal. A speed signal that has passed through one electronic card is divided into three to be input to three microprocessors(103,103a,103b) and then become input signals of intermediate value selectors(104). The output signals of the intermediate value selectors are applied to a final intermediate value selector(105). When a speed control signal that is the output signal of the final intermediate value selector is higher than a predetermined value, a comparator(106) generates an emergency stop signal. When at least two output signals of the three intermediate value selection electronic cards are higher than a value set by A/D converters(102,102a,102b), an emergency stop signal is generated. The two emergency signals pass through an OR-gate(108) to be a final emergency signal to stop the motor.

Description

The method of electrical overspeed protection and speed signal generation for speed control of prime movers for electric power generation}

The present invention relates to a method for generating an electrical overspeed protection and a speed control signal for a power generator. More specifically, the prime mover that imparts rotational power to the generator of a power plant is at the moment of separation from the power system, or the mechanical stress caused by the rapid increase in the centrifugal force of the rotating shaft in the overspeed state due to the failure of the controller or equipment exceeds the allowable limit of the material. There is a risk of rupture of the prime mover. Conventionally, six speed signal detectors are installed for the purpose of emergency stop to protect the prime mover in abnormal situation. The three speed signals for speed control are input to the control electronic card. The three overspeed protections are input to the protection-only electronic card, and three speed signal detectors are used for the program via each electronic card, and then used for overspeed protection by controlling the speed of the motor and overspeed protection. If two of the three speed signal detectors failed, a normal overspeed protection function could not be performed.

The present invention is intended to be applied to a power plant employing electric governors (EHC and D-EHC) as a prime mover, that is, a steam turbine, a hydraulic turbine, and a gas turbine, which are high-speed rotary machines operating in a power plant, exceeding the rated speed. In this case, it is to secure the safe operation by protecting the prime mover from the dangerous situation and to ensure the maximum reliability of the speed signal which is essential for the procedure of starting, operating and stopping the prime mover of the high speed rotating chain power plant.

The present invention is to electrically protect the prime mover from a dangerous situation in order to solve the problem that the normal overspeed protection function can not be performed when two of the three speed signal detectors used in the conventional overspeed protection and speed control occurs The objective is to secure safe operation and to ensure the reliability of the speed signal, which is essential for the procedures of starting, operating and stopping the prime mover of a high-speed rotating chain power plant.

1 is a field installation of nine gear and speed detectors mounted on a prime mover shaft.

2 is a flow chart illustrating a process of generating a speed control signal and an overspeed protection emergency stop signal from a controller by inputting nine pulse signals proportional to the speed of the prime mover;

3 is a flow chart showing an example (I) of conventional speed control signal generation and overspeed protection signal generation.

4 is a flow chart showing an example (II) of conventional speed control signal generation and overspeed protection signal generation.

<Description of the code | symbol about the principal part of drawing>

100: speed detector

101, 101a, 101b: hardware intermediate value selector (electronic card that outputs the intermediate value of three analog signals input)

102, 102a, 102b: A / D converters (contact signal is generated when the input analog signal exceeds the set value)

103, 103a, 103b: central processing unit of the controller

104: intermediate value selector (programmable intermediate value selector running on each microprocessor)

105: final median selector (from the three medians output from each microprocessor, the median is selected again and used as a speed control signal)

106: comparator (if the speed control signal exceeds the set value, it generates a digital signal)

107: 2 out of 3 voting (electric circuit that recognizes the result as true if two of the three digital input signals are true and false as two if the two are false)

108: logical sum gate

109: emergency stop

㉮: emergency stop signal

비상: Emergency stop signal via 2 out of 3 voting

㉰ = final emergency stop signal after ㉮ and ㉯ have passed the logic sum gate

In the conventional speed control signal generation and overspeed protection signal generation (Fig. 3), three speed signals, that is, pulse signals (output signals of the speed detector 1, the speed detector 2, and the speed detector 3) are controlled electronic cards (control P to A). Is converted into an analog signal. The three analog signals output from the control electronic card are input to the tripled controllers (controller 1, controller 2, controller 3). Three tripled controllers refer to the signal of the other controller and send the final output signal to the intermediate value selector.

The intermediate value selector performs speed control of the prime mover using the intermediate value among the three input signals. Three speed signals for overspeed protection, that is, pulse signals (speed detector 4, speed detector 5, speed detector 6) are inputted to a protection-only electronic card (emergency stop P to D). Is generated and input to the 2 Out of 3 circuit. When two digital signals are generated, an overspeed protection signal is output to emergency stop the prime mover.

In the conventional speed control signal and overspeed protection signal generation (FIG. 4), three speed signals for speed control, that is, pulse signals (output signals of the speed detector 1, the speed detector 2, and the speed detector 3) are input to the P to A converter. After being converted into an analog signal, the average value is selected by the average selector (software), and used as a signal for speed control and acts as an input to the A / D converter. If this signal exceeds the preset value in the A / D converter, an overspeed protection signal is generated and the prime mover is stopped.

The present invention is a hardware that can select the intermediate value of the pulse signal as shown in Figure 2 by using three sets of pulse signals generated by nine speed signal detectors installed to detect the speed of the prime mover as shown in FIG. The middle value selection of the images is distributed and input to three electronic cards 101, 101a, and 101b. The speed signals outputted through one electronic card are branched into three and input to three microprocessors 103, 103a, and 103b, and each microprocessor is input to software, that is, the input signal of the intermediate value selector 104 in the program. Function. The outputs of the three intermediate value selectors are input to the final intermediate value selector 105 on the program mounted on another microprocessor, and the output signal is used as a speed control signal. Therefore, the intermediate value selection is performed simultaneously in hardware and software. In addition, when the speed control signal is larger than a predetermined set value, an emergency stop digital signal is generated in the comparator 106 (Fig. 2). In addition, the three intermediate value selection electronic card output signals are set to 2 out of 3 bowing 107 on the hardware when at least two of the set values determined by the respective A / D converters 102, 102a, and 102b exceed the set values. The emergency stop signal is generated via (Fig. 2B). When the X signal of FIG. 2, that is, the software overspeed protection signal and the X signal of FIG. 2, that is, the overspeed protection signal on hardware, passes through the OR gate 108, the final emergency stop signal (X of FIG. 2) becomes. This signal becomes an emergency stop signal and is sent to the site, and consequently shuts off the working fluid flowing into the prime mover, causing the prime mover to emergency stop 109.

If two out of three conventional field speed detectors fail, normal protection operation cannot be performed.However, using the technique proposed in the present invention, the speed control and overspeed protection functions are normally performed even if the maximum five speed detectors fail. Can be done.

Claims (4)

Distributing and inputting into three intermediate value selection electronic cards 101, 101a, and 101b that can select the median value of the pulse signal generated by the speed signal detector installed to detect the speed of the prime mover; The speed signals outputted through the electronic card are divided into three, inputted to three microprocessors 103, 103a, and 103b, and then used as input signals of the intermediate value selector 104. The output signal is input to the final intermediate value selector 105, and the output signal is generated by the comparator 106 when the speed control signal is larger than a predetermined set value. The intermediate value selection electronic card (101, 101a, 101b) output signal is 2 out of 3 bowing on the hardware if at least two of the set values set in each A / D converter (102, 102a, 102b) exceed the set values. Rain via 107 When the phase stop signal (X in Fig. 2) is generated, and the X signal and X signal pass through the logical sum gate 108, it becomes the final emergency stop signal (X in Fig. 2) and is sent to the site to emergency the prime mover. A method of generating an electrical overspeed protection and a speed control signal of a power generator for a power generation, characterized in that for stopping (109). The method of claim 1, wherein nine speed detectors (100) are installed to be used in common for overspeed protection and speed control. The method of claim 1, wherein the intermediate value selection is simultaneously performed in hardware and software. The method of claim 1, wherein the overspeed protection signal of the hardware and the overspeed protection signal of the software are combined in a logical sum.