JPH023205B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water level adjustment device for a hydroelectric power plant that controls guide vanes of a water turbine according to the water level of a regulating pond and a surge tank provided upstream of the hydroelectric power plant.

Generally, in a conduit-type power plant, water upstream of the power plant is stored in a regulating pond from the headrace, and from there is supplied to the water turbine via the pressure headrace, surge tank, and pressure iron pipe, and after rotating the water turbine generator. ,
Water is discharged to the lower pond, and in order to adjust the amount of water discharged at this time, that is, the flow rate of the water wheel, according to the water level of the regulating pond and the surge tank water level, a water level adjustment device is provided.

Conventionally, in such conduit-type power plants, the surge tank water level did not need to be adjusted so strictly, so the water level adjustment device was also configured with the main purpose of adjusting the water level in the regulation pond, and the surge tank water level was not adjusted. , not much consideration was given to it.

However, recently, due to the effective use of water resources,
The water upstream of the power plant is used not only for power generation, but also for multiple purposes such as agricultural water and drinking water. A long pressure conduit is laid from the regulating pond, and a surge tank is installed near the fields or private sector. It has become common practice to extract water for domestic use.

For this reason, if a conventional water level adjustment device is applied to a recent waterway power generation plant, the surge tank water level will rise excessively when a flow disturbance occurs.
As a result of the downward movement, a large amount of water may instantly flow out of the surge tank, or water may not be able to be taken in.
There were drawbacks that had a negative impact on the surrounding living environment.

The present invention enables safe operation of a conduit power generation plant having a long pressure conduit and a not-so-large-volume surge tank without excessively raising or lowering the surge tank water level when a flow disturbance occurs. The purpose is to provide a water level adjustment device.

The present invention will be explained below with reference to the embodiments shown in the drawings.

FIG. 1 shows a conceptual diagram of a conduit-type power generation plant according to an embodiment of the present invention, where 1 is a headrace, 2 is
is a regulating reservoir, 3 is a pressure conduit, 4 is a surge tank,
5 is a pressure iron pipe, 6 is a guide vane, 7 is a water wheel, 8
is a generator, 9 is a lower pond, and 10 is a water level regulator (WLR).

This water level adjusting device 10 has a water level H _T of the regulating pond 2,
Using the water level H _S of the surge tank 4 and the opening degree η of the guide vane 6 as input, predetermined calculation processing is performed as described later, and the output drives the motor 11 to drive the guide vane 6 via the guide vane drive mechanism 12.
It is configured to adjust the opening degree of.

In addition, Q ₁ in the figure is the inflow amount to the regulating pond 2, and Q ₂
is the outflow amount from regulating pond 2, Q ₃ is surge tank 4
It represents the amount of outflow from the turbine, that is, the flow rate of the water turbine. Further, several water turbine generators are also connected to the surge tank 4 via pressure iron pipes (not shown), but in this embodiment, these water turbine generators do not have a water level adjustment function. Therefore, in the following description, the illustrated water turbine generator will be referred to as a water controller, and the unillustrated water turbine generator will be referred to as a non-water controller.

FIG. 2 shows the internal structure of the water level adjustment device 10, and also shows the other physical systems such as the waterway system and water wheel in FIG. ₁ in a block diagram. ,A ₂ ,
Gain circuit C ₁ , incomplete differentiation circuit C ₂ , low frequency correction circuit C ₃ , high frequency correction circuit C ₄ , increase command output circuit C ₅ , decrease command output circuit C ₆ , lower limit detection circuit C ₇ , upper limit detection circuit C ₈ , and consists of contacts S ₁ and S ₂ . In addition, in the figure, H _ref is the reference water level, HR is the water level drooping rate, which will be described later.
η _F is the guide vane opening bias, T _D is the incomplete differential time constant, K _D is the incomplete differential gain, H _H is the surge tank upper limit water level, H _L is the surge tank lower limit water level,
S represents a Laplace operator.

On the other hand, in the physical system other than the water level adjustment device 10, B _O is the motor 11, the guide vane drive mechanism 1
2 represents the overall transfer function of the drive unit consisting of the guide vane 6.

B ₁ and B ₂ are adjustments indicating that the water level H _T in the regulating pond 2 changes with the integral time constant T _HT due to the difference between the inflow Q ₁ to the regulating reservoir 2 and the flow rate Q ₂ in the pressure headrace 3. Pond 2
is the transfer function element of

B ₃ and B ₄ are transmission signals of the surge tank 4 indicating that the water level signal H _S of the surge tank 4 changes with an integral time constant T _HS due to the difference between the flow rate Q ₂ of the pressure headrace ₃ and its turbine flow rate Q 3 It is a functional element.

B ₅ and B ₆ are the water level H _T of regulating reservoir 2 and surge tank 4
This is a transfer function element of the pressure conduit 3 that indicates that the flow rate _Q2 of the pressure conduit 3 changes with a gain of 1/R and a first-order lag of the time constant L/R according to the difference from _the water level H S of .

B ₇ is the flow rate of the water turbine according to the opening degree η of the guide vane 6 of the water turbine 7, with the gain Q _R and the first-order lag of the time constant T _G.
This is a transfer function element of the water turbine 7 indicating that Q ₃ changes. Here, the gain Q _R indicates the rated flow rate of the water turbine.

In the configuration shown in the figure, if the surge tank water level is not fluctuating, that is, in a stable state, circuits C ₂ , C ₃ ,
C ₄ , C ₇ , and C ₈ are inactive, and the guide vane 6 is controlled according to the regulating pond water level H _T , and the water turbine flow rate Q ₃ is adjusted according to the relationship shown in FIG. 3.

In other words, the regulating pond water level H _T is set to the reference water level by adder A ₁ .
It is compared with H _ref , and its deviation output is multiplied by the reciprocal 1/HR of the water level droop rate HR in a gain circuit C ₁ and added to an adder A ₂ . The adder A ₂ adds the guide vane opening bias η _F to this to calculate the actual vane opening η and the deviation. The calculated deviation, that is, the operation signal is output from the increase command output circuit C ₅ or the decrease command output circuit C ₆ to the overall transfer function B ₀ via the closed contact S ₁ or S ₂ depending on its polarity,
The guide vane opening degree η is adjusted.

As a result, if the regulating pond water level H _T is at the reference water level H _ref , the turbine flow rate Q ₃ becomes the rated flow Q _R , and if the regulating pond water level T _T is lower than the reference water level H _ref by the water level droop rate HR, The guide vane 6 is fully closed and the water turbine flow rate Q ₃ is adjusted to zero.

On the other hand, when a non-water controller connected to the surge tank 4 starts, stops, or changes its output, or when a flow rate disturbance occurs immediately after the water controller is used from exclusion, the surge tank water level H _S may fluctuate significantly. becomes.
Regulation pond water level H _T and surge tank water level H _S at this time
The function of the incomplete differential circuit _C2 is to accelerate the attenuation of the water exchange between the regulating reservoir 2 and the surge tank 4 based on the difference between the two, and to stabilize the regulating reservoir water level H _T and the surge tank water level H _S. .

That is, when the surge tank water level H _S is decreasing due to a flow rate disturbance, a negative polarity signal proportional to the rate of decrease is input to the adder A ₂ to operate the guide vane 6 in the closing direction, thereby reducing the turbine flow rate Q ₃ , thereby suppressing the drop in the surge tank water level H _S and keeping the surge tank water level H _S constant. As a result, the water level H _T in the regulating pond is also stabilized, and the turbine flow Q ₃ is then adjusted according to the change in the inflow quantity Q ₁ of the regulating pond, that is, the change in the water level H _T in the regulating pond, while stabilizing the water level H _S in the surge tank. This can be adjusted.

In addition, due to flow disturbance, the surge tank water level H _S
A similar operation is performed when the value increases.

However, the values of the incomplete differential time constant T _D and the incomplete differential gain K _D of the incomplete differential circuit C ₂ are limited to suppress the exchange of water between the regulating pond 2 and the surge tank 4 due to minute changes in flow rate. It is set optimally. Therefore, when a flow disturbance occurs, the surge tank water level H _S reaches the upper and lower limits H _H , due to the inertia peculiar to water.
Attempting to deviate significantly from H _L. The function of circuits C ₃ , C ₄ , C ₇ and C ₈ is to prevent this.

That is, when the surge tank water level H _S falls below the lower limit water level H _L due to a flow rate disturbance, the lower limit detection circuit C ₇ immediately operates, opens its contact S ₁ and blocks the vane opening command to the motor 11 . At the same time, the low frequency correction circuit _C3 outputs a guide vane closing signal proportional to H _S - H _L and adds it to the adder _A2 . This guide vane closing signal decreases command output circuit _C3 , contact
As a result of the application to the motor 11 via S ₂ , the guide vane 6 is forced to move in the closing direction. This speeds up the recovery of the surge tank water level H _S and prevents the surge tank water level H _S from decreasing excessively.

In addition, due to flow disturbance, the surge tank water level H _S
A similar operation is performed when water is about to deviate significantly from the upper limit water level H _H.

Next, the operation of the water level adjusting device 10 described above will be specifically explained with reference to the time chart of FIG. 4.

In the figure, before time T ₀ , the water level H _T of the regulating pond is
It is assumed that the water level is slightly higher than H _ref −HR, and the water turbine flow rate Q ₃ is approximately 0. on the other hand,
It is assumed that the amount of inflow Q ₁ into the regulating reservoir 2 is gradually increased from time T ₀ by opening an upstream gate (not shown), and is finally increased to 2×Q _R . Furthermore,
It is assumed that the non-water controller is started at time T ₂ on the way, and its water turbine flow rate Q _X reaches the rated flow rate Q _R at time T ₄ .

Under the above assumptions, if we follow the changes in the regulating pond water level H _T , surge tank water level H _S , and turbine flow rate Q ₃ , at time T ₀
In the previous state, the surge tank water level H _S was
The water level is lower than H _ref −HR by the amount of loss in pressure conduit 3.

As the regulating pond water level H _T gradually rises from time T ₀ to _{T 1} , the water turbine flow rate Q ₃ of the water controller is increased. Then, especially when the pressure conduit 3 is long, the outflow amount Q 3 from the surge tank 4 changes faster than the inflow amount Q ₂ to the surge tank ₄ due to the increase in the water level H _T of the regulating pond. For,
The surge tank water level H _S is decreasing. The output of the incomplete differentiator C ₂ changes to suppress this downward direction, but as described above, the transient decrease in the surge tank water level H _S cannot be suppressed by the incomplete differentiator C ₂ . Therefore, the surge tank water level H _S will fall below the lower limit water level H _L from time T ₁ , but as soon as the surge tank water level H _S falls below the lower limit water level H _L , the lower limit detection circuit C ₇ will operate, and the contact will close. S ₁
is used to block the increase command to the motor 11.
At the same time, a guide vane closing signal proportional to H _S -H _L is output from the low frequency correction circuit C ₃ , and this signal is transmitted from the adder A ₂ to the reduction command output circuit C ₆ and the motor 11 via the contact S ₂ . , the turbine flow rate Q ₃ begins to decrease. As a result, the surge tank water level H _S recovers quickly, and during this period, the surge tank water level H _S remains at a level slightly below the lower limit water level H _L.

When the surge tank water level H _S recovers to the lower limit position H _L at time T' ₁ , the output of the low-frequency correction circuit C ₃ becomes 0, and the water turbine flow rate Q ₃ of the water controller at that time is the same as that at time T ₁ . Become. Then, at time T ₂ ,
When the water level H _T in the regulating pond rises to near the reference water level H _ref , the non-water regulator is started and the turbine flow rate Q _X begins to flow, but the surge tank water level H _S continues to rise due to the inertia unique to water. Eventually, at time T ₃ , when the surge tank water level H _S recovers to H _L +α, the lower limit detection circuit C ₇ becomes inoperable, and the contact S ₁ closes again.
As shown in Fig. 3, the water controller flow rate _Q3 is adjusted so that the water turbine flow rate is based on the regulating pond water level H _T.

On _the other hand, when _the non- _water controller flow rate _Q
At time T ₅ , the water level becomes lower than the lower limit water level H _L again. but,
At this time, the water level adjustment device 10 operates in the same manner as in the case of time T ₁ to T' ₁ , and despite the sudden change in _the non-water controller flow rate _Q Guide vane closing control prevents the surge tank water level H _S from dropping excessively and speeds up the recovery of the surge tank water level H _S to within the allowable value.

In this way, the surge tank water level is adjusted at time T′ ₅ , which is a shorter time than before from time T ₅ .
H _S becomes higher than the lower limit water level H _L and the output of the low frequency correction circuit C ₃ becomes 0, while the output of the lower limit detection circuit C ₇ becomes 0 until time T ₆ .
operates to keep the turbine flow rate Q ₃ constant and encourage the surge tank water level H _S to rise. Eventually, at time T ₆ when the surge tank water level H _S recovers to H _L +α, the lower limit detection circuit C ₇ becomes inactive, and as described above,
The turbine flow rate Q ₃ increases toward the rated flow rate Q _R , and the time
At T ₇ , the turbine flow rate Q ₃ reaches the rated flow rate Q _R.

After time T ₇ , the flow rate Q ₁ to the regulating pond 2 is _Q 3 , the water turbine flow rate Q ₃ of the non-water regulating machine _{is Q R ,} the regulating pond water level H _T is H _ref , and the surge The tank water level H _S becomes stable at a level lower than the regulating pond water level H _T by the difference in head loss based on the flow rate 2Q _R.

The above has been explained for the case where the surge tank water level H _S is in the decreasing direction, but in the same way when the surge tank water level H _S is in the rising direction, when the surge tank water level H S becomes equal to or higher than the upper limit water level H _H due to the operation of the high frequency correction circuit C ₄ . , H _S −H _H
The motor 11 controls the guide vane opening command proportional to
To prevent the surge tank water level H _S from rising excessively and to speed up the recovery of the surge tank water level H _S.

Therefore, when a flow disturbance occurs, the surge tank water level
H _S does not deviate significantly from the upper limit water level, and the amount of deviation can be minimized.
It becomes possible to significantly shorten the time it takes to return to within the limit value.

As a result, domestic water can be optimally supplied to the living area around the surge tank, making it possible to utilize water resources even more effectively.

At the same time, in the power generation plant, the upper and lower limit water levels can be set close to the permissible limit of the surge tank, and the value of the upper and lower limit width H _H - H _L can be set to a large value. As a result, it becomes possible to rapidly and frequently repeat starting and stopping of the water turbine generator, which is necessary for power supply. In addition, it is possible to widen the output fluctuation range of other units, increase the frequency of startup and shutdown, and greatly contribute to system operation. Furthermore, as the surge tank water level H _S can be prevented from rising or falling excessively, there is no risk of overflow or drought, or damage to civil engineering works, water turbine generators, etc. due to cavitation, etc., even though the vertical amplitude is increased. , the power plant will be fully operational.

Note that the low-frequency correction circuit C ₃ and the high-frequency correction circuit C ₄ in the above embodiment can also be realized together as a single dead band circuit. In addition, the low frequency correction circuit _C3 ,
The high frequency correction circuit C ₄ may be omitted, and constant close signal bias and open signal bias may be applied to the adder A ₂ by the ON outputs of the lower limit detection circuit C ₇ and the upper limit detection circuit C ₈ .

As described above, according to the present invention, when a flow disturbance occurs, the water level in the surge tank can be effectively used without excessively raising or lowering the water level, and the water level can be used to safely operate a canal power plant. A regulating device is obtained.

[Brief explanation of drawings]

Fig. 1 is a conceptual configuration diagram of a waterway power generation plant according to an embodiment of the present invention, Fig. 2 is a block diagram of its control system, Fig. 3 is a water level control diagram of its regulating pond, and Fig. 4 is its control system. This is a time chart to explain the operation. 1... Water conduit, 2... Regulating pond, 3... Pressure conduit, 4
... surge tank, 5 ... pressure iron pipe, 6 ... guide vane, 7 ... water turbine, 8 ... generator, 9 ... lower pond, 10 ... water level adjustment device, 11 ... control motor, 12 ... guide vane drive mechanism, A ₁ , A ₂ ... Adder, B ₀ ... Overall transfer function, B ₁ , B ₂ ... Transfer function element of regulating pond, B ₃ , B ₄
… Transfer function element of surge tank, B ₅ , B ₆ … Transfer function element of pressure conduit, B ₇ … Transfer function element of water turbine, C ₁ … Gain circuit, C ₂ … Incomplete differential circuit, C ₃
...Low range correction circuit, _C4 ...High range correction circuit, _C5 ...Increase command output circuit, _C6 ...Decrease command output circuit, _C7 ...Lower limit detection circuit, _C8 ...Upper limit detection circuit, S...Laplace operator, S ₁ , S ₂ ... Contact, Q ₁ ... Inflow amount, Q ₂ ... Outflow amount,
_{Q 3 , Q _ _}
Water level droop rate, T _D ... Imperfect differential time constant, K _D ... Imperfect differential gain, H _H ... Surge tank upper limit water level, H _L
… Surge tank lower limit water level, T _HT … Integral time constant, Q _R
…gain (water turbine rated flow rate), T ₀ to T ₇ … time.

Claims (1)

[Claims] 1. A guide vane opening signal of the water turbine according to the difference between the actual water level of the regulating pond and the reference water level, and a signal obtained by incompletely differentiating the water level signal of the surge tank installed in the waterway system between the regulating pond and the water turbine. Water level of a hydroelectric power plant that is equipped with an addition means for adding a guide vane opening bias signal of a water turbine and an actual guide vane opening feedback signal, and controls the guide vane opening according to an increase/decrease signal output from the addition means. In the adjusting device, when the water level of the surge tank becomes equal to or lower than the lower limit value, a low-frequency correction means applies to the adding means a signal in a direction to close the guide vane, which is proportional to the difference between the water level and the lower limit value; a high-frequency correction means that applies, to the adding means, a signal in the direction of opening the guide vane that is proportional to the difference between the water level and the upper limit when the water level exceeds the upper limit; means for blocking the output of the guide vane opening direction increase signal outputted from the addition means and for unblocking the output when the water level exceeds the lower limit value by a predetermined value; The invention is characterized by comprising means for blocking the output of the guide vane closing direction reduction signal outputted from the adding means, and unblocking when the water level falls below the upper limit value by a predetermined amount. Water level adjustment device.