JP2000080972A - Output adjustment controller for hydroelectric power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform control suitable for elimination or prevention of abnormalities caused by abnormality factors by quickly detecting the hunting of output control caused by surging generated in the conduit system of a hydroelectric power plant or independent running by the remote control operation of an electric wire. SOLUTION: In the abnormality detecting section 200 of an output adjustment controller 10, means 201, 202 and 203 are provided to detect the peak deviation and the peak cycle of the actual output Pd of a generator. A function generator 204 having areas preset according to abnormality factors including 'independent running', 'surging', 'sudden command change' and the like inputs the peak deviation and the peak cycle of Pd, and outputs '1' when entering any of these function areas. A cycle determination section 205 takes in the peak cycle, and outputs '1' to cycle range of a corresponding abnormality factor. AND 206 to 208 respectively identify 'surging', 'independent running' and 'sudden command change', outputs abnormality generating signals and perform locking for an increasing/decreasing command 65PR/PL.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output adjustment control device of a hydroelectric power plant which performs a follow-up control with respect to an output command value. The present invention relates to a control device for preventing such a situation.

[0002]

2. Description of the Related Art A hydroelectric power plant is unmanned, and an output command value of an output adjustment control is numerically controlled by a remote control.
Frequency control (generally called AFC) is performed.
For output adjustment, the amount of water used is adjusted according to the opening degree of the guide vane. When the amount of used water is changed in accordance with a change in output, a sharp rise or fall in pressure or hydraulic pulsation occurs.
A surge tank is provided between the pressure tunnel and the penstock so that the water hammer does not directly reach the penstock.

[0003] However, when the sudden change of the output coincides with the cycle of the surge tank, a resonance phenomenon occurs, and the water level changes greatly, and there is a risk of exceeding the reference water level of the surge tank. For this reason, the frequency characteristics of the surge tank and the frequency characteristics of the guide vane opening / closing operation are analyzed, and the surge tank capacity is determined so as to suppress fluctuations in the water level of the surge tank within a stable limit (see “The latest high-class electric test course; Vol., Hydroelectric Power Station, Denki Shoin, 1976).

Further, it is known that the output of a water turbine fluctuates due to the water hammer action and water pressure pulsation of a water channel system, and there is a known example in which surging is detected from the fluctuation cycle of the output value and the output is locked (Japanese Patent Application Laid-Open No. H10-157,197). 59-5882, 5883).

On the other hand, when the transmission line is opened due to an accident or the like,
In some cases, an isolated operation is performed in which a generator supplies power to a small system. FIG. 9 shows an electric power system that is operating independently. When the transmission line is opened as indicated by the mark x, the generator G performs the isolated operation of the power P1 with a small load L.
The load of the generator G is controlled by the speed control device GOV.
The control gain of V is increased. However, at the time of isolated operation, the control gain is too large and becomes unstable, leading to divergence or a limit cycle.

[0006]

The central power supply command station outputs a power supply command to the hydroelectric power plant in response to a load change at the end of the transmission line. For this reason, the command value of the output adjustment control of the hydroelectric power plant often changes suddenly, reflecting the momentary load fluctuation. Water turbine operation due to a sudden change in the output command causes water hammer action and water pressure pulsation, and the output of the turbine is often fluctuated. In addition, during islanding operation by remote cutoff of the transmission line,
The control system becomes unstable and the turbine output fluctuates. Surging of the water system due to water hammer, vibration of the control system due to isolated operation, and the like may lead to serious accidents if not addressed immediately.

As described above, the fluctuation of the actual output in the hydroelectric power plant includes a plurality of abnormal factors in addition to the sudden change of the command value, and these may be overlapped to cause abnormal fluctuation. However, since there is no method for discriminating between the plurality of abnormal factors, there has been a problem that appropriate operation control for eliminating abnormalities cannot be quickly performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydroelectric power plant output adjustment control device which discriminates an abnormal factor of output fluctuation of a hydroelectric power plant and quickly eliminates the abnormality according to the factor in view of the problems of the prior art. It is in.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an output adjustment control device for a hydroelectric power plant, which operates a guide vane of a turbine to control the output of a generator rotated by the turbine. Output command (Pre
f) and an output command generation unit that generates a command to increase or decrease the opening degree of the guide vanes in accordance with a deviation between the actual output (Pd) of the generator and a plurality of hydropower stations based on the generator output vibration function. A plurality of abnormal vibration regions caused by the abnormal factors are set, and the maximum value and the minimum value of the actual output (Pd) are obtained in real time. An abnormality detection unit that issues an abnormality signal when entering any of the abnormal vibration regions.

Here, the generator output oscillation function is an actual output (Pd) whose deviation from the output command (Pref) is zero.
Is a function indicating a change from the steady state with reference to the steady state, and is a vibration function represented by two elements of a changing amplitude and a period (or frequency).

The abnormality detecting section detects the abnormality signal when a change in the output command obtained in real time is equal to or less than a predetermined value and a pair of a peak deviation and a peak cycle of the actual output enters the abnormal vibration region. Issuing is characterized. That is, abnormal vibration of the actual output Pd that does not depend on a change in the output command Pref is regarded as abnormal occurrence.

[0012] In addition, due to the above-mentioned abnormal factors, the generator is operated independently (hereinafter, referred to as "independent operation") by remote cutoff of a transmission line, and the surging of the water system of the hydroelectric power plant (hereinafter, referred to as "surging").
And an abrupt change of the output command (hereinafter referred to as a command abrupt change) is included, and when each abnormal vibration region is set to be differentiated by a cycle (or frequency) characteristic, the abnormality detection unit issues an abnormality to be issued. It is characterized in that the cause of the signal abnormality is discriminated based on the peak period of the actual output. In addition,
The setting of the abnormal vibration area for each factor may be performed by a fuzzy function.

Further, an abnormality handling control unit corresponding to the cause of the abnormality is provided, and in the case of the single operation, a control gain for operating the guide vane is reduced. Further, in the case of the surging, the output of the increase / decrease command is locked, and in the case of the sudden change of the command, the output command is held at the previous value and an alarm is issued to the power supply station.

Alternatively, the abnormality detecting section obtains a maximum value and a minimum value of the output command in real time, and a pair of a peak deviation and a peak cycle (time difference) based on the maximum value and the minimum value is an abnormal vibration area of the command sudden change. Judge whether to enter,
When entering, the output of the abnormal signal due to the actual output is suppressed and an alarm is issued to the power supply station. That is, when the fluctuation of the actual output Pd is following the output command Pref, the corresponding control may be reserved assuming that an abnormality has occurred, and an alarm may be issued for the time being to see the situation.

The abnormality detecting section issues the abnormality signal when the pair of the peak deviation and the peak cycle of the actual output enters the abnormal vibration region and the peak deviation increases from the previous value. It is characterized by the following. That is, it is determined whether the fluctuation of the actual output Pd is in the enlargement direction or the contraction direction, to avoid a quick response to the transient change, and to ensure the stability of the control.
Further, by monitoring the enlargement direction in real time, the occurrence of an abnormality can be detected at the stage of its sign, and the occurrence or enlargement of the abnormality can be prevented.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an overall configuration diagram of a power plant according to an embodiment to which the present invention is applied. In the hydroelectric power plant, the upper dam 1 and the lower dam 2 are connected to a water turbine 5 through a pressure tunnel 3 and a penstock 4, and a surge tank 6 is installed between the pressure tunnel 3 and the penstock 4. In the electric system, the generator 9 is connected to the transmission line 13 via the main transformer 7 and the parallel circuit breaker 8.

The output adjustment control device 10 includes the output detection device 1
1 and an output command value Pref, which is a power supply command from a central power supply command center, and outputs an output increase command 65PR and an output decrease command 65PL to the water turbine controller 12. The water turbine control device 12 generally includes a governor control device and an actuator (mechanical system), and the governor control device controls the guide vane opening in response to a guide vane increase / decrease command.

FIG. 1 shows the configuration of an output control device according to one embodiment. The output control device 10 includes an output command generator 100 shown in the upper half of the dashed line and an abnormality detector 200 shown in the lower half. The output command generation unit 100 outputs the output command Pre by remote control.
f and the actual generator output Pd are input, the difference between Pref and Pd is calculated by the subtracter 101, and the output adjuster 102 outputs increase / decrease commands 65PR and 65PL according to the difference. Command 65PR, 65
The PLs are provided by AND circuits 103 and 104, respectively.
Logical operation with the output from the
The output of the decrease command 65PL is blocked.

The abnormality detecting section 200 receives Pd and generates a function corresponding to the maximum value detecting section 201, the minimum value detecting section 202, the cycle detecting section 203, and the cycle (time difference) of Pd and the difference between the maximum value and the minimum value. Function generator 204, period determination unit 205, and AND circuits 206 to 208 for performing arithmetic processing on their outputs, and NOT circuit 209
It consists of a logic circuit consisting of

Next, the operation of the output control device 10 will be specifically described. FIG. 3 shows a temporal change of the output command Pref and the actual output Pd. In this example, the pulsation occurs in the actual output Pd even though the output command Pref is constant. Maximum value detector
201 and minimum value detector 202 is the maximum value P ₁ and the minimum value P ₂ of the actual output Pd, maximum value P ₃ and the minimum value P _4,. . . Is detected in real time, and the period detection unit 203 detects the time differences t ₁₂ and t ₁₂ between the peaks.
_23, t _34. . . And the function generator 204 calculates | P ₁ −P ₂
│ and t _12, │P ₂ -P ₃ │ and t _23, │P ₃ -P ₄ │ and t _{3 4,.} . . Are successively output as function values ('0' or '1') corresponding to. In the other sets to which the output command Pref is input, since Pref is constant, the peak deviation and the peak cycle are 0, and the output of the function generator 204 is “0”.

FIG. 4 is a conceptual diagram showing the generation of a function by the peak deviation and the peak period. The function generator 204 has an actual output P
For the peak deviation and the peak period (time difference) of d, a function in the shaded area shown in the figure is set. In this shaded region, an abnormal range such as surging resonance or vibration caused by isolated operation is set in advance. Then, when the peak deviation and the peak cycle of Pd are within the range of the shaded region, “1” is output, and when it is out of the range, “0” is output. Since the peak deviation is small and the peak period is short between P1 and P2 in FIG. 3, it is outside the range of the setting function. However, P2 to P3 and P3 to P
4 is within the setting range of the function generator 204, so that the output becomes "1", indicating the occurrence of an abnormality.

By the way, the oscillation cycle of the isolated operation is 20
The vibration period due to surging is 60 to 120 seconds. The vibration cycle of the command sudden change that induces surging is 90 to 150 seconds. In the present embodiment, the function generator 204 is set with the respective area functions of “independent operation”, “surging”, and “command sudden change”.

FIG. 5 is an explanatory diagram of a function generator having a setting function for each abnormality factor. The hatched area (a) with a peak cycle of 20 to 30 seconds is a function of "independent operation", and a peak cycle of 60 to 1
A hatched area (b) of 20 seconds indicates a function of “surging”, and a hatched area (c) of a peak cycle of 120 to 150 seconds indicates a function of “command sudden change”. Note that the oscillation cycle of "surging" differs depending on the length of the water channel and the amount of water, and tuning is performed according to the power plant.

When the peak fluctuation of the actual output Pd enters the function setting area, the output of the function generator 204 changes from "0" to "1" and is output to the AND circuits 206 to 208. On the other hand, the cycle determination unit 205 determines whether the current peak cycle is “40 to 90 seconds” or “less than 40 seconds” according to the peak cycle from the cycle detection unit 203.
It is determined whether it is “more than 90 seconds”, and “1” is output to the output terminal of the corresponding cycle. The output terminal of each period range is AN
D circuits 206, 207, and 208 are connected. If there is an overlap in the periods of the function setting areas of the function generator 204, "1" is output to a predetermined priority or both.

The output of the AND circuit 206 is output to the function generator 20
4 is “1” and the current peak cycle is “40 to 90”.
Seconds ”, that is,“ 1 ”upon detection of“ surging ”, and is input to the ANDs 103 and 104 via the NOT 209. Therefore, the increase / decrease commands 65PR and 65PL from the output command generation unit 100 to the water turbine control device 12
4 locks until the surging is removed.

The output of the AND circuit 207 is output to the function generator 20
4 is “1” and the current peak cycle is “less than 40 seconds”, that is, “1” upon detection of “single operation”, and is transmitted to the water turbine controller 12. The water turbine controller 12 receiving this lowers the speed control gain to a predetermined value,
Oscillation due to "independent operation" is prevented. At the same time, the increase / decrease command may be locked.

The output of the AND circuit 208 is output from the function generator 20
When the output of No. 4 is “1” and the current peak cycle is “more than 120 seconds”, that is, it becomes “1” upon detection of “command sudden change”. In the case of "command sudden change", an alarm (30-Pref) is output to the remote control because it causes "surging" or the like. Further, the output command value Pref is held at the previous value,
Prevent the occurrence of abnormal phenomena in advance.

FIG. 6 shows an output command value holding circuit. The holding circuit 220 is provided at an input unit of the output command Pref of the output command generation unit 100. The holding circuit 220 sets the alarm output 30Pref to 0.
When ⇒1, Pref is held at the previous value, and when 30Pref is 1⇒0, Pref is output as it is.

According to the present embodiment, as an abnormal factor which appears in the fluctuation of the actual output of the generator, it is possible to discriminate an isolated operation, a surging or an abnormal power supply command, and to perform a corresponding control according to a factor such as locking of the control system. Since it can be executed promptly, it is possible to eliminate or prevent the abnormality.

FIG. 7 shows the configuration of an output control device according to another embodiment. The main difference from FIG. 1 lies in that an abnormality detection function of the output command Pref and a deviation direction determination function are provided.

The abnormality detection function of the output command Pref includes a maximum value detection unit 211, a minimum value detection unit 212, a cycle detection unit 2113,
a function generator 214 for generating a function corresponding to the difference between the period (time difference) of f and the maximum value-minimum value, and a period determination unit 205;
The configuration is similar to that of the actual output Pd. However, the function generator 214 only needs to set the "command sudden change" area,
The function generator 204 need not have the “command sudden change” area.

Thus, when Pref enters the area of "command sudden change", the output of the function generator 214 becomes "1", and an alarm "30-Pref" for the remote control is output. Although similar to the case of FIG. 1, the change in the output command is directly monitored, so that the “command sudden change” can be detected quickly.

On the other hand, the function generator 204 outputs “1” to the AND circuit 210 when the vibration characteristic of the actual output Pd falls within the “single operation” or “surging” region. In addition, the deviation direction determination circuit 215 inputs the maximum value and the minimum value of Pd, obtains the peak deviation, compares it with the previous peak deviation, and when the present deviation value is large (vibration is expanding). 1 is output to the AND circuit 210 when the present deviation value is small (the vibration is reduced). Further, the NOT circuit 216 outputs “1” to the AND circuit 210 when the output of the function generator 214 is “0”, that is, when there is no “command sudden change” of Pref.

Thus, the AND circuit 210 detects an abnormality of “single operation” or “surging”, and determines that an abnormality has occurred if the abnormality is in the enlargement direction and no abrupt change is found in the output command. To output '1'. Therefore, the reliability of abnormality determination can be improved, and erroneous determination due to transient vibration or the like can be avoided. Further, the output of the deviation direction determination circuit 215 may be monitored and detected as a sign of an abnormal phenomenon when the enlargement direction continues. These enable early detection and prevention of abnormal phenomena.

The AND circuit 210 is divided for each factor.
An abnormality may be discriminated by the same cycle determination unit as in FIG. 1 and control may be performed according to the cause of the abnormality. Alternatively, FIG.
May be added to the abnormality detection unit 200 of the first embodiment.

In the above embodiment, the functions of the peak deviation and the peak period of the abnormal vibration of the actual output of the generator are set in advance for each cause of the abnormality and discriminated. The setting of the function corresponding to each factor can be made by past performance values, simulations, and the like. However, the range to be set in advance may not be limited due to the water level difference between the upper dam and the lower dam. in this case,
The function of the peak deviation and the peak period is set by a fuzzy function, and fuzzy inference is performed.

FIG. 8 shows a membership function with the peak period as input. In the figure, A indicates the degree of certainty of "independent operation", B indicates "surging", and C indicates the degree of certainty of "command sudden change". The certainty is tuned based on the peak deviation for each factor, with the probability of occurrence of an abnormality of 100% being 1.0 and the probability of occurrence of an abnormality of 0% being 0.0. According to this, since the complicated operation of the waterway system can be expressed by the fuzzy function, the configuration of the abnormality detection unit becomes easy.

In the above embodiment, the actual output of the generator was used to detect the islanding operation. However, the frequency of the transmission line was used as an input, and the frequency fluctuation and the period generated when the transmission line was cut off at the far end were set as functions. Can also be achieved.

Further, in variable speed pumped-storage power generation, AFC is performed by changing the rotation speed even during pumping. However, since the change in the rotation speed changes the amount of water used, water pressure pulsation occurs. Therefore, by using the same circuit configuration with the input of the rotation speed command and the actual rotation speed instead of the input of the output command and the actual output, it is possible to discriminate the same cause of abnormality as described above.

[0040]

According to the present invention, a plurality of abnormal vibration characteristics of a hydroelectric power plant are compared with the vibration characteristics of the actual output of the generator. Since the determination is made, there is an effect that the abnormality can be quickly detected.

Further, since the cause of the abnormality is discriminated from the vibration cycle at the time of occurrence of the abnormality, and the control for eliminating or preventing the abnormality is performed according to the cause, the safe operation of the hydroelectric power plant can be ensured.

[Brief description of the drawings]

FIG. 1 is a block diagram of an output adjustment control device of a hydroelectric power plant according to one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a hydroelectric power plant to which the present invention is applied.

FIG. 3 is a time change diagram of an example of an output command and an actual output.

FIG. 4 is a conceptual diagram showing a setting region of an abnormal characteristic in a hydroelectric power plant.

FIG. 5 is an explanatory diagram showing setting regions of a plurality of abnormal characteristics according to one embodiment.

FIG. 6 is a configuration diagram of a hold circuit of the output adjustment control device.

FIG. 7 is a block diagram of an output adjustment control device of a hydroelectric power plant according to another embodiment of the present invention.

FIG. 8 is an explanatory diagram showing an example in which a setting region of an abnormal characteristic is set by a fuzzy function.

FIG. 9 is an explanatory diagram showing a system configuration during an isolated operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper dam, 2 ... Lower dam, 3 ... Hydraulic tunnel, 4 ... Hydraulic iron pipe, 5 ... Turbine, 9 ... Generator, 10 ... Output adjustment control device, 11 ... Output detection device, 12 ... Water turbine control device, 100
... Output command generator, 102 ... Output adjuster, 103,10
4: AND circuit, 200: abnormality detection unit, 201, 211
... Maximum value detectors, 202, 212 ... Minimum value detectors, 20
3. Period detection unit, 204, 214 ... Function generator, 205
... Period determination unit, 206-208 ... AND circuit, 209 ...
NOT circuit, 210: AND circuit, 215: deviation direction determination circuit, 216: NOT circuit, 220: hold circuit.

Claims (6)

[Claims] 1. An output adjustment control device for a hydroelectric power plant, which operates a guide vane of a water turbine to control an output of a generator rotated by the water turbine, wherein an output command from a central power supply station and an actual output of the generator are An output command generation unit that generates a command to increase or decrease the guide vane opening in accordance with the deviation; and sets a plurality of abnormal vibration regions in advance due to a plurality of abnormal factors of the hydroelectric power plant based on a vibration function of a generator output. In addition, a maximum value and a minimum value of the actual output are obtained in real time, and an abnormal signal is issued when a pair of a peak deviation and a peak cycle (time difference) based on the maximum value and the minimum value enters any of the abnormal vibration regions. An output adjustment control device for a hydroelectric power plant, comprising: 2. The abnormal detection unit according to claim 1, wherein the change of the output command obtained in real time is equal to or less than a predetermined value, and a pair of a peak deviation and a peak cycle of the actual output enters the abnormal vibration region. The output adjustment control device of the hydroelectric power plant, wherein the abnormality signal is issued at times. 3. The method according to claim 1, wherein the abnormal factors include a single operation of the generator (hereinafter, referred to as “single operation”), a surging of a water system of the hydroelectric power plant (hereinafter, “surging”), and a sudden change of the output command. (Hereinafter referred to as a command sudden change), and when each abnormal vibration region is set to be differentiated by a cycle (or frequency) characteristic, the abnormality detection unit determines the cause of the abnormality of the abnormal signal to be issued by the actual condition. An output adjustment control device for a hydroelectric power plant, which performs discrimination based on a peak cycle of output. 4. The control device according to claim 3, further comprising an abnormality handling control unit corresponding to the cause of the abnormality, wherein the control gain for operating the guide vane is reduced in the case of the single operation, and the increase / decrease command is locked in the case of the surging. ,
In the case of the command sudden change, the output command is held at the previous value and an alarm is issued to the power supply station.
An output adjustment control device for a hydroelectric power plant, comprising: 5. The abnormality detection unit according to claim 3, wherein the abnormality detection unit obtains a maximum value and a minimum value of the output command in real time, and a pair of a peak deviation and a peak cycle based on the maximum value and the minimum value is the command sudden change. And determining whether or not the vehicle enters an abnormal vibration region. If the vehicle enters, suppresses the output of the abnormal signal based on the actual output, and issues an alarm to the power supply station. 6. The abnormality detection unit according to claim 1, wherein a pair of a peak deviation and a peak cycle of the actual output enters the abnormal vibration region, and the peak deviation increases from a previous value. The output adjustment control device of the hydroelectric power plant, wherein the abnormal signal is issued when the power is on.