JPH03215125A - Power system supervisory control system - Google Patents

Abstract

PURPOSE:To decide the condition of stability of a system voltage and inform the results of decision stepwisely by estimating a total demand and distributing an amount, corresponding to the amount of change, to respective loads and generators. CONSTITUTION:An increasing solution and/or decreasing solution obtaining means S10 effects power float operation based on system information to obtain an increasing solution of voltage and a decreasing solution of the same. A total demand increasing means S20 estimates the total demand under a condition that system constitution and phase control facilities are not changed. A respective loads and respective generators distributing means S30 distribute an amount, corresponding to the amount of this change, to respective loads and respective generators. The increasing solution and/or decreasing solution obtaining means S40 carriers out the power flow operation again after said distribution to obtain the increasing solution and the decreasing solution sequentially. A P-V curve estimating means S50 obtains a proximate P-V curve based on a plurality of increasing solutions and decreasing solutions, which are obtained by the means S30, S40. A voltage stability condition deciding means S60 obtains the margin of power and the amount of demand increasing limit from the means S50 and outputs them through an output means S70. The results of deciding of the stability condition of the system voltage can be informed to an operator at every several stages and stabilized operation can be effected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a power system monitoring and control system that supports the stable supply of high quality power with high reliability.

Conventional technology> In the conventional power system monitoring and control system, the system voltage cannot be controlled. When monitoring, the current state of the grid voltage is displayed, and it is monitored whether it is within the upper and lower limits of the specified voltage operation target value, and if it is outside the range, an alarm is issued. I try to do that.

(Problem to be Solved by the Invention) As described above, in the conventional system, the stability of the grid voltage is left to the judgment of the operator. However, there was no way to know where the voltage stability limit was, so when a unique power system situation that had not been experienced in the past occurred, such as an unexpectedly heavy load or a sudden change in load. When this occurs, depending on the situation, it may become uncertain whether the system voltage can be maintained stably.

The present invention was made in view of the above circumstances, and it calculates the p-v curve of the current power system and the future power system (predicted system several minutes or hours ahead), and calculates the current voltage margin and demand increase. By determining the stability state of the grid voltage by determining the limit amount, future electric shock margin, and demand increase limit amount, and notifying the operator of the results in several stages, more stable operation of the power system can be achieved. The purpose of this project is to provide a power system monitoring and control system that supports the system.

Ellipsis of the Invention] (Means for Solving the Problems) The configuration for achieving the above object will be explained with reference to FIG. In a power system monitoring and control system that inputs data into the system, processes the information based on this information, and outputs various data regarding voltage stability to a display device, it processes the information based on the system information input via the information transmission device. The first means (S10
), the total demand is assumed on the condition that the system configuration and phase adjustment equipment do not change (S20>), and a second means (8) of allocating the amount corresponding to this change to each load and each generator
30), a third means (S40) for sequentially obtaining a higher solution and a lower solution by performing the power flow calculation again after the distribution, and a plurality of higher solutions and lower solutions obtained by the second and third means. A fourth means (S5
0), a fifth means (S60) for determining the voltage margin and the limit increase in demand from the fourth means, and a sixth means (S70) for outputting the results obtained by the fifth means. Configured.

(Operation) Execute power flow calculations in the current power system or future power system to determine higher solutions (■■ in HO Figure 3) and lower solutions (■).
■、。 ■) in Figure 3 is determined, and then the system configuration is determined. Assuming that the operating status of the adjustment teeth does not change, the total demand is changed by ΔP, and each load and each generator output power are corrected accordingly, and then the power flow calculation is executed again to find a higher solution (■ in Figure 3 of VH1). )
and lower solutions (■, 1 in Figure 3)), and then repeat the same operation twice to obtain 4 higher solutions and 4 lower solutions.

Next, from the 4 higher solutions (■HO"H1"H2" H3), find a PV curve that approximates the 4 points with a quadratic curve using the method of least squares, and from the 4 lower solutions (■10"11"12" L
From 3), P approximates the four points with a quadratic curve using the least squares method.
−■ Find the curve. Furthermore, near the stability limit (4th figure force 0)
V to find the P-■ curve of. 2” H3'■12.
A P-■ curve is obtained by approximating the four points of X'13 by a quadratic curve using the method of least squares. Finally, from the P-■ curve obtained, the voltage margin (ΔV (■ in Figure 4)) and the demand increase limit (ΔP limit ([Phase] in Figure 4) are determined to determine the stability state. , and outputs the results to a man-machine interface such as a CRT.

(Example) Examples will be described below with reference to the drawings.

For convenience of explanation, the explanation will start from FIG. 2, which is a diagram showing an example of the configuration of the power system monitoring and control system according to the present invention.

In FIG. 2, 1 is an electric power system, and an information transmission device 2-1 that measures the state of this electric power system and transmits the measured value.
, an information transmission device 2-2 that receives the information via the transmission line 3, a computer 4 that receives this information and processes the voltage stability, and a man-machine that displays the processing results of the computer 4. - Consists of an interface device (H old) 5.

FIG. 1 is a flowchart of the present invention in which the computer 4 performs processing related to voltage stability state determination, in which the high solution/low solution solving means S10, 540 and the total demand increment means 3 are used.
20 and each load. It consists of each generator distribution means S30, p-v curve estimating means S50, voltage stability state determination stage 860, and output means S70.

Next, I will explain the effect.

The higher solution/lower solution solving means S10 transmits information from the power system 1 to the information transmission device 2-1 . Perform power flow calculations using the current power system or future power system (predicted system for several minutes or several hours ahead) received via 2-2 as the initial value (total demand Po), and calculate the higher solution in Figure 3 and Get a lower solution.

Since the P-■ curve is a curve that represents the relationship between total demand and voltage when the system configuration and the operating status of the harmonizing equipment do not change, the total demand increment means is Perform S20.

The total demand incrementing means S20 assumes the total demand by adding the incremental demand ΔP to the total demand from the previous calculation, but since the power flow calculation often does not converge near the point [F] shown in FIG. , ■ in Figure 3. ■． ■． Once ■ is obtained, estimate the P-■ curve to find the limit increase in demand, and if that value is small, reduce the incremental demand ΔP and assume the total demand so that it does not exceed the voltage limit point. do. Each load and each generator distribution means S30 performs an operation of distributing the generator output and load values by the amount of change ΔP in order to balance the total demand changed by the total demand increment means S20. The distribution method is to proportionally distribute the change ΔP for the active power P, and to distribute the reactive power Q by calculating the change in Q at a constant power factor with respect to the change in the active power P.

however, : Effectiveness of the i-th load after the total demand change electric power : Invalidation of i-th load after total demand change electric power P1 1”f’: Active power of the i-th load before demand change : Invalidation of i-th load after total demand change electric power Q Q P becomes.

The system assumed above is considered as the basic system and is highly resolved.
A higher solution and a lower solution are determined by the lower solution solving means S10. By repeating this process, you can get higher solutions■,■. ■． ■、Lower solution■
, ■, ■, ■ are obtained. ■、■■． ■、■． ■． ■． Since ■ may not be approximated by a quadratic curve, the P-■ curve estimating means S50 calculates ■. 4 points of ■, ■, ■ r2 P-a1'v + b1V + CI ---
---(i) is approximated by the quadratic curve, and the parameter a1b of equation {1). c 1 is ■. Identification is performed using the least squares method 1 from the values of ■, ■, and ■, and a P■ curve of the portion shown by ■ in Fig. 4 is obtained. ■ By the same method. From the four points ■, ■, ■, obtain the P-■ curve of the part shown by ■ in Figure 2, and ■. ■． ■． ■
From the four points, the p-v curve of the part shown by ◎ in Figure 2 is obtained.

The voltage stability state determining means S60 determines the voltage margin and the limit amount of demand increase from the P-■ curve obtained in the means S40.

for example vHO+VEO Voltage margin one system voltage 2 Demand increase limit = Total demand limit - Po ■Ho: Total demand P. Higher voltage solution Lower voltage solution for “LO’ total demand P. Total demand limit value: This is the total demand at point [F] in Figure 4.

The output means S70 determines to which level the voltage margin and demand increase limit determined by the means S60 belong according to a preset level, and displays and outputs an alarm message corresponding to the level.

As described above, according to this embodiment, various data regarding the stability of the voltage of the power system can be appropriately provided to the operator.

[Effects of the Invention] As explained above, according to the present invention, current and future voltage stability limits and stability can be appropriately provided to the operator regarding the system voltage of the power system, and as a result, it is possible to take prompt action. This makes it possible to monitor and operate the power system with even higher quality, making it possible to provide a more stable supply of electricity.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing the processing content regarding voltage stability performed by the present invention, Fig. 2 is a diagram showing an example of the configuration of the power system monitoring and control system according to the present invention, and Fig. 3 shows solutions for increasing and decreasing voltage based on total demand. Figure 4, which is a diagram plotted after finding the solution, shows the relationship between the method of approximating the P-■ curve, the voltage margin, and the limit amount of demand increase. S10. S40...Solving means S for higher and lower solutions
20...Total demand increment means S30...Each I load. Each generator distribution means S50...p
-v curve estimating means S60... Voltage stability state determining means S70... Output means

Claims (1)

[Claims] In a power system monitoring and control system that inputs system information from the power system to a computer via an information transmission device, processes this information based on it, and outputs various data regarding voltage stability to a display device. The first means calculates the power flow based on the system information input via the information transmission device to obtain higher and lower voltage solutions, and the first means calculates the power flow based on the system information input through the information transmission device, and the total method is calculated on the condition that the system configuration and phase adjustment equipment do not change. A second means for estimating the demand and allocating the amount corresponding to this change to each load and each generator; and a third means for calculating the power flow again after the distribution to sequentially obtain a higher solution and a lower solution. and a fourth means for obtaining an approximated PV curve based on the plurality of higher solutions and lower solutions obtained by the second and third means,
A power system monitor characterized by comprising: a fifth means for determining a voltage margin and a limit increase in demand from the fourth means; and a sixth means for outputting the results obtained by the fifth means. control system.