JPS59103525A - Interlocking power controlling method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an active power control device, particularly an active power control device having an interconnection transmission line, and in which an interconnection line power flow schedule is given as a target power amount for each unit time. Regarding the method of controlling the case.

[Prior art]

Conventionally, two control methods, economic load distribution control and frequency control, have been combined to control the active power generated in a power system.

Of these, economic load distribution control targets load fluctuation components with a relatively long period of about several minutes, and usually predicts the load fluctuation curve of the day based on past load results, and uses the predicted curve to The effective power of the entire system is estimated, and a power generation target value is given to each power plant in advance to match this estimate. The command value for each power plant determines the power generation target value for each power plant using the law of equal incremental fuel costs so as to be most economical for the entire system. The law of equal incremental fuel costs and its theoretical explanation are described in "Power System Engineering" (written by Taiji Sekine, Denki Shoin), etc.

On the other hand, frequency control is performed for relatively short load fluctuation components of several seconds to several tens of seconds, and from the frequency deviation Δf and the interconnection line power flow deviation ΔPT with the adjacent power system, the power imbalance amount ΔP is calculated as follows. Calculate as shown in the formula.

ΔP = KΔf + ΔP.

=K(fj”o)+PT−PTO・−・−・(1) K knee system constant f: Actual gravity system frequency f: Reference frequency PT: Actual interconnection line power PT (1: Reference interconnection line power (Target value) ΔP is, so to speak, the generated active power deviation of the entire system, but
The sum of the proportional value and the integral value of this ΔP is distributed to each generator in a feedback manner (Frequency control is also explained in books such as the above-mentioned "Power System Engineering", so details regarding the theory will be omitted here. ).

The active power control device is configured as shown in FIG.

That is, the frequency f measured in the power system I and the interconnection line power Pt of the adjacent power system are input to the frequency control device 2, and the power imbalance amount ΔP is determined. ΔP is distributed to each generator via a proportional and dividing circuit.

On the other hand, the total power demand (ΣP) measured in the power system is input to the load prediction device 3, and a correction amount is given to the predicted load curve obtained in advance to predict the total power demand after a certain period (control period). used. The economical load distribution device 4 distributes the predicted load so that the total fuel cost is minimized according to the fuel characteristics of each generator, and instructs it as a base output to each power plant or generator. The output of the economic load distribution control device 4 and the output 2 of the frequency control device are combined and transmitted to each power plant or generator. These two output values may be transmitted separately and combined at the power plant.

Recently, there are many cases in which such control mechanisms are implemented using electronic computers.

Here, when controlling the interconnection line power, proportional-integral control is performed based on the instantaneous value of the deviation of the force between the actual interconnection line force and the reference interconnection line.

The purpose of interconnection is as follows.

1) Even if an accident occurs in power equipment, other equipment will continue to supply power in its place, increasing supply reliability.

2) Since the supply reserve capacity can be pooled among all the tonne companies, the burden of reserve capacity on each tonne company can be reduced, and equipment costs can be saved.

3) Even in daily operation, when the power generation cost of another system is low, power generation costs can be reduced by purchasing power from that system.

4) By interconnecting, it becomes possible to use large-capacity equipment, and economic effects due to economies of scale can be obtained.

In this way, interconnection of electric power systems greatly contributes to stable and economical operation of electric power, but on the other hand, an accident within one system can spread to other interconnected systems. Or,
There are also adverse effects, such as disturbances in active power control in one system affecting other interconnected systems. Therefore, in order to prevent each other's active power control from having an adverse effect on each other during normal times, the hourly interconnection power flow power amount is determined in advance for each hour, and this hourly schedule [be sure to follow] The method uses active power control.

However, looking at equation (1) here, in conventional automatic active power control, the control amount is determined by the instantaneous value of the interconnection line power flow deviation, so the hourly scheduled power amount can always be met. There is no guarantee. For this reason, in recent active power control devices, the operator corrects the calculation of ΔP as follows, so that the hourly schedule capacity can be maintained.

ΔP=K(f-fo)+Pt-Pro+ΔPs-(2)
ΔPB: Correction amount set by the operator Furthermore, in order to automate the control to maintain such an interconnection line power flow power amount schedule, the following control is being attempted.

ΔP=K(f?o)+PrPro+ΔP8+ΔPc
・-・-(3) ΔPcPc Dual power line power automatic correction value Integrated value of interconnection line power deviation from every hour on the hour [8: Time measured from every hour (seconds) Generated interconnection line power l1
The 11-tub difference is then distributed evenly over the remaining time in that one hour period to compensate. By doing this, it is possible to automatically control the effective power so as to maintain the interconnection line power amount every hour. , which gives the feedback control amount, so Δ in equation (3)
Terms such as P8 and ΔPc will impose disturbances on frequency control.

For example, if the correction is performed at the end of an hour as shown in FIG. 2, the denominator of equation (4) is small, so ΔPC becomes small. For this reason, too much effort is made to maintain the interconnection line power amount according to the schedule, which results in a negative effect on system frequency stability. That is, in this method, the area of the shaded area before the calculation time shown in FIG. 2 is equal to the area of the shaded area after d1°1. Therefore, in a time period in which yPr deviates significantly from the prediction, a large ΔPc is output in the second half of the hour in order to reset the power deviation up to that point. If a large ΔPc is superimposed on the frequency control signal as in equation (3), the frequency e and number control will be disturbed by that amount.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to realize an active power control device having an interconnection line power amount control function in coordination with grid frequency control.

[Summary of the invention]

The present invention focuses on the fact that a target is set so that the interconnection line power amount falls within a certain range around the schedule value, and the limit value is set in the first half of the time period in which the interconnection line power amount is monitored. A first limit value is set to be small and the limit value increases as the end of the time period approaches, and a second limit value is set to be smaller than the first limit, and the second limit value is set to be smaller than the first limit value. When the grid power amount exceeds the first limit value, the power amount is corrected by a predetermined value minus the power amount (load reduction control is performed, and the grid power amount is made smaller than the second limit value. The feature is that the power amount correction is canceled when the power amount correction is reached.

[Embodiments of the invention]

The present invention will be explained in detail below. FIG. 3 is a diagram of the equipment of the embodiment (1\composition).The frequency measurement value and the generated power are transmitted from the variable type RGR 36 to the information transmission line 35 and the information transmission device 34.
It is fed into the coupling device 33 through. electronic computer 31
inputs these data via the coupling device 33.

The auxiliary storage device 32 stores programs and long-term data necessary for performing active power control. A cathode ray tube display device 37 and an operation console 38 are used for a man-machine interface with an operator. The printer 39 is used to output control results and report documents. The input data is processed q4 times in total by an electronic computer in the same manner as shown in FIG. 1, and command values for each power plant are outputted from the coupling device to the power plants.

Next, FIG. 4 shows the processing procedure performed inside the computer with such a device configuration.

1. By the method described later, the power generation power independent and equilibrium ΔP+ at the time of calculation (time point 1) is determined.

2) Calculate the integral and proportional components of ΔPI and combine them as shown in the following equation to obtain the control output ΔP1'.

Here, al and a are weight distribution constants for integral and proportional components.

3) Allocate ΔP+' to each power plant or generator.

The method of allocation is to allocate in proportion to the currently generated power of each power plant or generator. The currently generated power is input to the computer through the transmission line.

4) Transmit and output the distributed command values to each power plant or generator.

Frequency control is performed by repeating such processing at a constant period of about several seconds. Economic load distribution control also
In the same way, calculations are performed at a longer fixed period and combined with the frequency control output to form the power generation command value.

Here, the procedures 1) to 4) are the same as conventional active power control, but the generation power imbalance amount ΔP1
The method of calculation is different from the conventional method.

FIG. 6 shows how to obtain this ΔPI.

Further, FIG. 5 diagrammatically shows the state of this interconnection line correction. Next, how to obtain ΔPI, which is the key point of [Mizumoto ψ], will be explained using a 2n6 diagram.

1) Check whether the Rt37 point is on the hour.
)do. The hour on the hour is the division of unit time at which the interconnection line power amount schedule value is given.

For example, if the hourly Lianyu Line Power Supply is scheduled, 0 o'clock, 1 o'clock, 2 Pi'... river will be on the hour.

2) Integrate the power flow Pt+ currently flowing through the interconnection line into the interconnection line i power amount deviation as follows.

u+ = ut-t + (Pt+ - Po 1)/I Here, ■ is the number of frequency control processes performed in one hour, and Po+ is its schedule value.

3) Initialize the correction amount. (ΔPc+=0)4)
When either of the following two conditions is satisfied, a fixed value ΔPco or −ΔPc6 is given to the correction amount ΔPcI.

(1) When interconnection line power amount correction has started but has not yet been completed and Jul) DLx is output.

(11) Interconnection line power amount correction is not cultivated and 1u1
>When DLl.

The sign of ΔPco is opposite to that of U.

Here, the start of interconnection line power correction refers to the point in time when (11) is satisfied for the first time within a certain unit time.

5) Find ΔPI using the following formula.

ΔPs = K (f I - fo ) + Pt 1 - PTO
I+ΔPcI Here, since the systematic constant is known in advance, it is stored in the auxiliary storage device or the main storage device in the computer. Reference frequency fo and reference interconnection line power PT◎
is set and inputted by the operator using the polar ray tube display device and the operation console, and the measurement frequency f is input.

and interconnection line power Pt1 are transmitted from the power plant or substation.

At step 4), two dead zones D L l and DLz appear, but as shown in FIG. 5, these values change temporally within a unit time. By providing a larger dead zone after a unit time, unnecessary correction operations are prevented, and the interconnection line power ffl deviation within a unit time is suppressed to a constant level. In addition, since the correction amount ΔPco is one step, it has a large negative impact on frequency stability rt? It has no effect on

FIG. 7 shows this situation graphically. The solid line in the figure shows the case where the interconnection line does not perform power control, and the broken line indicates the case where the interconnection line power control is performed.In the conventional method A correction signal ΔPc is output.Also, it can be seen that a large ΔPc is output toward the end of the unit time giving the interconnection line power amount schedule.On the other hand, in the method according to the present invention, the interconnection line A constant correction signal is output only when the power amount deviation is large, so
Frequency control is not disturbed by excessive correction signals. Furthermore, although the interconnection line power amount deviation becomes 0 in the conventional method at the end of the unit time, it does not necessarily become 0 in the method according to the present invention. This may seem like a shortcoming of the sample method, but the purpose of the control is to bring the interconnection power amount within the target range, and even if it is within the range, it may not match the schedule value exactly. Considering the positive aspects, this method is superior in that it does not perform unnecessary control operations.

Next, the dead zones DLI and DL2 in FIG. 5 will be explained. The dead zone D L 1 can be expressed as shown in F.

Komude uII is the power amount deviation allowed per unit time. When = 0, consider that u = = Q, and the control objective 2 is l = 1][1, Iul > un, and a small deviation that occurs at the beginning within unit time [ This dead zone curve is designed based on the idea that it can be left alone. The insensitivity %i'DLz is K D L 1 in order to stabilize ΔPc by giving hysteresis to the control.
Make it a small straight line.

If Pc6 is too large, the disturbance given to frequency control will be large, and if it is too small, no control effect will be produced. For example, if the influence of interconnection line power amount deviation on frequency control is 0.
If it is less than 01H2, Pco ” 0.01 X
It can be calculated as K.

In this manner, according to the present embodiment, it is possible to perform schedule control of the grid-connected power amount per unit time without adversely affecting the frequency control.

In addition, in this embodiment, there are two dead bands (DL* and DIJ).
2) B) 1 The magnitude of ΔPCO was kept constant, but the number of dead zones was increased, and several different magnitudes of ΔPco were prepared accordingly, so that when the deviation was large, a large ΔPc
It is also possible to perform more fine-grained control by outputting .

According to the present invention, it is possible to perform automatic active power control that keeps the power amount schedule between interconnection lines within a permissible value without adversely affecting frequency stability.

[Brief explanation of the drawing]

FIG. 1 is an example of a block diagram of a conventional active power control device.
Fig. 2 shows the current correction amount 801: an example, Fig. 3 shows the device configuration in an embodiment of the present invention, and Fig. 4 shows a frequency control flowchart in an embodiment of the present invention. ,
Figure 5 shows the explanation of the interconnection line power amount deviation and dead zone at this time.
FIG. 6 is an S-th γ flowchart of unbalanced power generation loading ΔF+, and FIG. 7 is a comparison diagram between the conventional method and the method according to the present invention. 1... Power system to be controlled, 2... Frequency control device,
3...Load prediction device, 4...Economic negative f distribution device, 31...Electronic computer, 32...(iii auxiliary storage device, 33...Coupling device, 34...Information transmission device 1.
L, 35... Strange/tυ transmission line, 36... Source, substation, 37... Cathode ray tube display device, 38... Operation console, 3
9...Printer. Agent Patent Attorney Akio Takahashi Fue 2 Figure 3 (2) 4th (2) Tsume 50th 60th 70th

Claims (1)

[Claims] 1. A power control method in a power system that is connected to an indirect power system and an interconnection transmission line when the power flow limit flowing through the interconnection line is given as the power product n per unit time. a first power amount limit value that increases as the limit value approaches the end of the unit time period and becomes the permissible value of the interconnected power amount at the final time of the time period; and a second power limit value set to a value smaller than the power limit value, and when the integrated power amount exceeds the first limit value, the load is limited by a predetermined amount. . A grid-connected power control method, characterized in that the load restriction is canceled when the integrated value of the grid-connected power amount becomes smaller than the second limit value.