JPH061999B2 - Variable speed turbine generator system controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a turbine or pump turbine provided with a guide vane, a generator or generator-motor directly connected to the turbine or pump turbine, and Control for controlling the speed and output of a variable speed turbine power generation system composed of a variable frequency power supply that applies exciting power to a generator or generator motor by the opening of a guide vane and the exciting power of the generator or generator motor It relates to an improvement of the device.

(Prior Art) The efficiency η of a turbine is the unit speed n (however, the unit speed is the speed N
Is a speed normalized by the head, and n = N / √H)
And the guide vane opening degree a
Shown as shown. That is, as is apparent from FIG. 4, the conventional turbine operates at a constant N, so in a power plant with a large variation in head difference or in a power plant with a large output range operated and a large guide vane opening variation range. , Are forced to drive inefficiently. From this, in order to perform highly efficient operation regardless of the head and output,
A variable-speed turbine power generation system in which the speed of the turbine is changed according to the head and the output has begun to be studied (for example, "JP-A-57-113971").

FIG. 5 shows an example of this type of variable speed turbine power generation system. In FIG. 5, on the secondary winding of the induction generator 2 directly connected to the water turbine 1 equipped with the guide vanes 1A,
By applying the output of the variable frequency power source 3 as the exciting power, the primary winding of the induction generator 2 generates a power synchronized with the system. On the other hand the control device includes an output control unit 5 from the output request P ₀ to generate an output command E _R of the variable frequency power source 3, and a said output request P ₀ and electrostatic drop H _ST, the speed command N _R with the maximum efficiency a function generator 7 for outputting a speed control unit 6 for outputting the guide vane opening command a _R based on the speed command N _R from the function generator 7,
The guide vane control device 4 controls the guide vane opening A so that the guide vane opening command A _R from the speed controller 6 is controlled.

According to the above configuration, the guide vane opening A is the output demand P
₀ and electrostatic drop H _ST and by the control of the guide vane opening command A _R to achieve a speed command N _R determined, also the excitation power E of the induction generator 2 is the output of the variable frequency power source 3 to realize a output request P ₀ is controlled to the command E _R, it is possible to perform efficient operation.

However, in the control device of the variable speed turbine power generation system as described above, there is a disadvantage that the transient characteristics are poor. As an example, the static drop H _ST , the output P ₁ , the speed N ₁ ,
From the first operating point, which is the guide vane opening A ₁ and the exciting power E ₁ , the static drop H _ST , the output P ₁ + ΔP, the speed N ₁ + Δ
N, guide vane opening A ₁ + ΔA, excitation power E ₁ + ΔE
The transient characteristic when changing to the second operating point is described. For the sake of simplicity, it is assumed that the static head does not change.

That is, when the static drop H _ST is constant, the input / output characteristic of the function generator 7 is approximately N _R = K ₁ P ₀ . Where K ₁
Is a positive constant determined by the head. Therefore, in order to change from the first operating point to the second operating point, the output request P
₀ Increasing ΔP from _{P 1,} the speed command _{N R} from _{N 1} delta
N increases, the output command _{E R} also increases ΔE from _{E 1.} As a result, both the guide vane opening A and the generator excitation power E start to increase. Further, the relationship between the change dA of the guide vane opening A and the change dP _M of the turbine output P _M is represented by a transfer function as shown below, as is well known.

However, T _W is the channel constant determined by the channel cross-sectional area and channel length,
It is usually about 0.6 to 2.0 seconds. On the other hand, since the delay of the generator output P is about several milliseconds due to the change of the generator excitation power E, the increase of the output demand P ₁ is faster than the increase of the turbine output P _M , and the speed N is decreased. I will end up. Further, due to the delay from the change dA of the guide vane opening A to the change dP _M of the water turbine output P _M , the characteristics of the speed control unit 6 have poor stability and poor responsiveness. Therefore, the settling of the speed N is slow as shown in FIG. 6, and it takes time to reach the second operating point.

(Problems to be Solved by the Invention) As described above, in the conventional control device for the variable speed turbine power generation system, the stability when the speed and output of the variable speed turbine power generation system are controlled by following the output request. However, there was a problem that the system could not be operated efficiently because of poor performance and responsiveness.

Therefore, in the present invention, the speed and output of the variable speed turbine power generation system are controlled stably and quickly by following the output request, and a highly reliable variable speed turbine power generation system capable of always performing efficient operation is provided. An object is to provide a control device.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, a turbine or pump turbine provided with a guide vane, and a generator directly connected to the turbine or pump turbine, or The speed and output of a variable-speed turbine generator system composed of a generator-motor and a variable-frequency power source that applies excitation power to this generator or generator-motor, the opening of the guide vane, and the generator or generator-motor In a control device that controls with excitation power, an output control unit that outputs a guide vane opening command according to an output request, and a guide vane that has an opening according to a guide vane opening command from the output control unit. A guide vane control device that controls the opening, and a guide vane opening command based on either the guide vane opening command from the output control unit or the guide vane opening. Output response compensator that outputs the opening reference, the function generator that outputs the speed command based on the guide vane opening reference from this output response compensator, and the static head, and the speed from this function generator. It is characterized in that it is configured to include a speed control unit that outputs an output command to the variable frequency power supply so that the speed corresponds to the command.

(Operation) In the control device of the variable speed turbine power generation system described above,
The output control by the guide vane opening control and the speed control by the excitation power control from the variable frequency power source are simultaneously performed, and the control for obtaining the generator output at a speed with high efficiency of the water turbine is realized according to the output request. Further, in response to a rapidly changing output request that cannot be completely tracked by the guide vane opening control, the generator output can be tracked by temporarily changing the speed reference.

(Example) Hereinafter, the present invention will be described with reference to an example shown in the drawings.

FIG. 1 shows a configuration example of a variable speed turbine power generation system to which the control device according to the present invention is applied, and the same element names as those in FIG. 5 are designated by the same reference numerals. In FIG.
Variable speed composed of a water turbine 1 having a guide vane 1A, an induction generator 2 directly connected to the water turbine 1, and a variable frequency power source 3 for applying exciting power to a secondary winding of the induction generator 2. The control device for controlling the speed and output of the turbine power generation system consists of the following. That is, the guide vane opening command A according to the output request P ₀
An output control unit 5 for outputting _R, guide vane controller 4 for controlling the guide vane opening A such that opening corresponding to the guide vane opening command A _R from the output control section 5
And the guide vane opening command A _R from the output control unit 5
Based on an output response compensation unit 8 for outputting the guide vane opening reference A _R1 serving as a reference when obtaining the optimum speed, the guide vane opening reference A _R1 from the output response compensation unit 8
When, a function generator 9 for outputting a speed command N _R based on a static drop H _ST, the speed command from the function generator 9 N _R
Are to be configured with a speed control unit 6 for outputting the output command E _R to said variable frequency power supply 3 so that the response rate to.

Here, the output control unit 5 includes a generator 51 that detects a deviation between the generator output P detected by an output detector (not shown) and the output request P ₀ , and a proportional-plus-integral controller 52.
The speed control unit 6 and the speed N detected by the speed detector (not shown), a subtraction unit 61 for detecting the deviation ΔN of the speed command N _R described above, it constitutes a proportional controller 62. Further, the function generating unit 9 obtains the speed at which the efficiency becomes maximum when the guide vane opening degree and the static head difference are given, from the turbine characteristic. Furthermore, the output response compensating unit 8 obtains the guide vane opening reference input to the function generating unit 9 so that the output response becomes good, and the detailed calculation method will be described later.

Next, the operation of the control device of the variable speed turbine power generation system configured as described above will be described with reference to FIG.
Note that FIG. 2 (a) is a block diagram showing the operating characteristics of the entire control system in FIG.

In FIG. 2 (a), Gp (S) is the output control unit 5
Is a characteristic of the proportional-plus-integral controller 52 of FIG.
If p and the integration time constant are Tp, Becomes Further, G _T (S) is a guide vane opening command A _R
Is a response of the turbine output P _M to, and when the delay time constant of the guide vane control device 4 is T _V and the waterway time constant is T _W , normally T _V << T _W. Becomes Further, K ₁ is a value obtained by linearly approximating the guide vane opening-versus-speed characteristic of the function generator 9 near the operating point. T
Is an inertial time constant of the water turbine 1 and the induction generator 2, K _N is a proportional gain of the proportional controller 62 of the speed control unit 6, and K _N >> 1.

On the other hand, Gc (S) shows the characteristic of the output response compensator 8, but if the equivalent conversion on the block is performed in order to clarify the role that Gc (S) plays in the output control, FIG.
become that way. As is clear from FIG. 2 (b),
It can be seen that it is possible to improve the response of the output P with respect to the guide vane opening command A _R. Note that Gc (S) = 0
It goes without saying that the above case becomes the output control system of the conventional constant speed turbine power generation system.

Next, how to determine the Gc (S) will be described.

Now, when the desired response of the output P to the guide vane opening command A _R is P = Gx (S) A _R, and the response improvement amount of Gc (S) is Gc (S), Gc (S) is obtained, Becomes As an example, if Gx (S) = 1, Becomes However, since in order to perform efficient operation of the water turbine 1 is always desirably Gc (S) is 1, for the fast component from the output control reply guide vane opening command A _R Gc (S ) ≈Gc ′ (S), and Gc (S) is determined so that Gc (S) = 1 for a component slower than the output control system response of the guide vane opening command A _R ,
Gc (S) is calculated by the following equation.

As a result, the change from the first operating point shown above to the second operating point is as shown in FIG. From FIG. 3, it can be seen that, with respect to the same output request P ₀ , the stability of the speed N is improved and the initial response of the output P is improved as compared with FIG. 6 described above.

As described above, in the control device of the variable speed turbine power generation system having the configuration of the present embodiment, output control by guide vane opening control and speed control by excitation power control from the variable frequency power source are performed at the same time, and an output request is made. In order to realize a control that obtains a generator output at a highly efficient speed of the turbine according to the above, and for a rapidly changing output request that cannot be followed by the guide vane opening control, the speed reference is temporarily changed. This allows the generator output to be tracked. As a result, the reverse response in the initial stage of output change due to the influence of the waterway system seen in the output response of the conventional constant-speed turbine power generation system, that is, when the output is increased (or decreased), the output temporarily decreases (or increases). There is no phenomenon. Moreover, in accordance with the output demand, the operating point is highly efficient, that is, the speed and guide vane opening, which are the most efficient for generating the output at the time of the static drop, are reached quickly, and the extremely efficient power generation operation is achieved. It is possible to obtain the effect that it becomes possible to perform.

It should be noted that the present invention is not limited to the above-described embodiments, but can be carried out as follows.

(A) above in the embodiment of FIG. 1, as the output response compensation unit 8 has been described a case of outputting the guide vane opening reference A _R1 based on the guide vane opening command A _R from the output control section 5 Not limited to this, even if the output response compensating unit 8 outputs the guide vane opening reference A _R1 based on the guide vane opening A, the same operational effect as described above can be obtained.

(B) In the above embodiment, the case where the present invention is applied to the variable speed turbine power generation system including the turbine and the induction generator directly connected to the turbine has been described. The present invention can be similarly applied to the variable speed turbine power generation system including the generator motor.

In addition, the present invention can be variously modified and implemented within the scope of the invention.

[Effects of the Invention] As described above, according to the present invention, an output control unit that outputs a guide vane opening command according to an output request, and an opening degree according to the guide vane opening command from the output control unit. A guide vane control device for controlling the guide vane opening degree so that the guide vane opening degree command from the output control unit,
Alternatively, a speed command is output based on the output response compensator that outputs the guide vane opening reference based on either of the guide vane opening, the guide vane opening reference from this output response compensator, and the static head. Since the function generator and the speed controller that outputs the output command to the variable frequency power source so that the speed corresponds to the speed command from the function generator are provided, the variable speed turbine generator system is provided. Stable and quick control of the speed and output of the
It is possible to provide a highly reliable controller for a variable speed turbine power generation system that can always perform efficient operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a variable speed turbine power generation system to which a control device according to the present invention is applied, and FIG. 2 (a) is a block diagram showing characteristics of the entire control system in the embodiment, FIG. 2B is an equivalent block diagram of the response characteristic in FIG. 2A, FIG. 3 is a diagram showing the response characteristic in the same embodiment,
FIG. 4 is a diagram showing characteristics of a water turbine, FIG. 5 is a configuration diagram showing an example of a conventional variable speed turbine power generation system, and FIG. 6 is a diagram showing response characteristics in FIG. 1 ... Turbine, 1A ... Guide vane, 2 ... Induction generator, 3 ...
Variable frequency power source, 4 ... Guide vane controller, 5 ... Output controller, 51 ... Adjuster, 52 ... Proportional-integral controller, 6 ... Speed controller, 61 ... Adjuster, 62 ... Proportional controller, 7 ... Function Generator, 8 ... Output response compensator, 9 ... Function generator, P ₀
Output request, P output, A _R guide vane opening command,
A ... guide vane opening, H _{ST ...} static drop, N R _... speed command, N ... speed, E R _... variable frequency power output command, the excitation power of the E ... induction generator 2, P M _... hydraulic turbine output.

Claims (1)

[Claims] 1. A turbine or pump turbine having a guide vane, a generator or generator motor directly connected to the turbine or pump turbine, and a variable frequency power source for applying exciting power to the generator or generator motor. In a control device that controls the speed and output of a variable speed turbine power generation system by the opening of the guide vane and the excitation power of the generator or generator motor, a guide vane opening command is output according to the output request. Output control unit, a guide vane control device that controls the guide vane opening so that the opening is in accordance with the guide vane opening command from the output control unit, and a guide vane opening command from the output control unit. , Or an output response compensator that outputs a guide vane opening reference based on the guide vane opening, and a guide vane from this output response compensator. A function generator that outputs a speed command based on the opening degree reference and the free fall difference, and a speed control that outputs an output command to the variable frequency power supply so that the speed corresponds to the speed command from the function generator. And a control unit for a variable speed turbine power generation system.