JPH03215126A - Power system supervisory control system - Google Patents

Abstract

PURPOSE:To estimate the system condition of future properly by a method wherein an estimated total future demand is operated from a difference between an actual total demand and a total demand obtained statistically as well as the changing rate of the difference. CONSTITUTION:A total demand estimating means S11 is interposed after a system condition determining means S10 to detect a difference between an actual total demand and a total demand obtained statistically from accumulated data in the past as well as the changing rate of the difference. A total demand estimating means S11 corrects the statistically obtained total demand by the difference and the changing rate of the difference and operates an estimated total demand in future. A future system condition estimating means S20 estimates the system condition in future based on the present system condition, determined by the means S10, and the total demand estimated by the means S11. As a result, the future system condition can be estimated properly by estimating the future total demand with a good accuracy even when the total demand is being changed suddenly whereby more stabilized operation of a power system can be supported.

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 past, the stability of grid voltage was left to the operator's judgment, but recently a method that automatically determines voltage stability and calculates the necessary adjustment amount has been attracting attention. became.

FIG. 3 shows an example of the configuration of a power system monitoring and control device for this purpose, and includes an information transmission device 2-1, 2-2 that measures the state of the power system 1 and transmits the measured value via the transmission line 3, and voltage stabilization. It is composed of an electronic computer 4 that performs processing related to degrees, and an H old device 5 that displays processing results.

In FIG. 3, the computer 4 receives the voltage and output of the generator from the information transmission device 2-2, the active power and reactive power of the load, the active power flow, the reactive power flow, the bus voltage, the circuit breaker and the disconnection. The measurement data of the power system status such as the opening/closing status of the equipment and the tap position of the transformer is processed in terms of voltage stability.
Data regarding various voltage stability is displayed on the H old device 5.

FIG. 4 is a flowchart showing an example of the means by which the computer 4 performs processing related to the stability of grid voltage, which includes grid state determination processing S10, future grid state prediction processing S20, stability limit calculation processing S30, and stability monitoring processing. S40, effect size calculation process S50, adjustment amount calculation process S60, and output process S7
Consists of 0.

In FIG. 4, the system state determination process S10 uses measurement information including errors of the power system inputted from the information transmission device to determine the most probable state value of the power system by a weighted least squares estimation method.

The future system state prediction process S20 predicts the future system state based on the current system state determined in the process S10 using the following procedure.

The load power and generator output after Δt with respect to the current time t are determined as follows.

[SL(t+Δt)−Stft)] ...(
1) QL. (t+Δt)=QL. (t)+PF. (t)
[PL (t soil Δt) - PL (t) ] ... (
2) pa. (t + Δt): Obtained from the total demand SL (t + Δ1) using the driving schedule J Yule and economic load distribution.

...(3) VG. (t+Δt): Determine from the VR operation reference value pattern. ...(4) Here, PL. (t+Δt): Active power QL of load i at time t+Δt; Effective power PG of load i at time t+Δ1. (t+Δt) J active power VG. of two generators J at time t+Δ1. it + Δt): J voltage of generator j at time t+Δ1 PFit): Power factor Sl of load i at time t
(t): Total demand at time t At this time, the power factor of the load and the total demand use values statistically determined from past data that has been classified and accumulated by season, day of the week, and time.

Power flow calculations are performed using the above values as constraint conditions.

Next, by simulating the response of independent control devices such as individual VQCs and determining the future state of voltage regulating equipment such as capacitors, reactors, and transformer tags, and performing the current flow calculation again, the final state at the future time is determined. Obtain accurate power system status data.

Stability ■ field calculation process S30 inputs the result of process S20 to determine the voltage stability limit at a future point in time, and stability monitoring process 54
0 uses the results of processing S20 and processing 530 to determine the stability of the power system at a future point in time, and effect size calculation processing S50 uses the results of processing S20 to determine the voltage stability of the power system voltage regulating equipment at a future point in time. An adjustment amount calculation process S60 calculates the amount of adjustment of the voltage adjustment equipment necessary to stabilize the system voltage when it is unstable in the future by calculating the results of processes S40 and S50. The output process 870 is the process 810 . 820S30, S40. S50
, various data resulting from S60 are displayed on the H old device 5.

(Problem to be solved by the invention) In future electric power system monitoring and control systems, future power system conditions have been predicted using total demand statistically determined from past data. If the voltage changes, it is not possible to appropriately predict the future grid state, and depending on the situation, there is a risk that it will be uncertain whether the grid voltage can be maintained stably.

The present invention has been made in view of the above circumstances, and even when the total demand is changing rapidly, the future power system state can be appropriately predicted by accurately predicting the future total demand, thereby improving the power system. The purpose of this project is to provide a power system monitoring and control system that supports even more stable operation of power systems.

[Evaluation of the Invention] (Means for Solving the Problems) The configuration for achieving the above object will be explained with reference to FIG. 1. The present invention is composed of an information transmission device, an electronic computer, and a man-machine interface device, A system state determination means (S10) that determines the state of the power system, and a future system state prediction means (S20) that predicts the future system state from the current system state.
), a stability limit calculation means (S30) that determines the voltage stability limit for the future system state, and a stability limit calculation means (S30) that determines the degree of stability of the future system voltage from the future voltage stability limit. a monitoring means (S40), an effect amount calculation means (S50) for determining the effect amount for increasing voltage stability of the means for improving future voltage stability, and a method for stabilizing future system voltage when it is unstable. An adjustment amount calculation means (360) that calculates the amount of adjustment necessary for Output means (5
70), a total demand forecasting means (S1
1) to detect the difference between the actual total demand and the total demand statistically determined from past accumulated data and the rate of change in the difference, and correct the statistically determined total demand from this difference and rate of change. The system was configured to calculate the future predicted total demand using the corrected predicted total demand, and to predict the future system status using the corrected predicted total demand.

(Function) The system status determining means determines the status of the power system using measurement information including power system errors input from the information transmission device, and the total demand forecasting means determines the status of the power system based on past performance and current total demand. Predict future aggregate demand for a short period of time. The future power system state prediction means predicts the future state of the power system in a short time based on the current power system state determined by the power system state determination means and the short time future total demand predicted by the total demand prediction means. predict,
The stability limit calculation means uses the results of the future system state prediction means as an initial value to determine the stability limit of the system voltage, and the stability monitoring means uses the results of the future system state prediction means and the stability inverse limit calculation means. to determine the level of voltage stability of the future power grid. The effect size calculation means uses the results of the future system state prediction means to determine the effect size of the voltage regulating equipment to increase voltage stability, and the adjustment amount calculation means uses the results of the stability monitoring means and the effect size calculation means , the amount of adjustment required to stabilize the unstable state of the system voltage in the future is determined, and the output means is used to output the various results of the above-mentioned means to a man-machine interface device such as a CRT.

(Example) An example will be described below with reference to the drawings. The configuration of the power system monitoring and control system according to the present invention is the same as the conventional configuration shown in FIG. 3, so a description thereof will be omitted.

FIG. 1 is a flowchart of the implementation means of the present invention in which the electronic computer 4 performs processing related to the stability of grid voltage, including grid state determination processing S10, total demand prediction processing S11, future grid state prediction processing S20, and stability limit calculation. The process includes a process S30, a stability monitoring process S40, an effect amount calculation process S50, an adjustment amount calculation process S60, and an output process S70.

Next, the operation will be explained, or in FIG. 1, the process S10.
S20. 330, S$, S50. S6
0. 570 C Since the means are the same as the means with the same number in the prior art shown in FIG. 4, the explanation will be omitted.

The total demand forecasting means 11 calculates the current time t and Δ using the total demand statistically determined from past accumulated data and the actual total demand.
C. Find the total demand after Δt with respect to the previous total demand as follows.

ΔSL(t) =SLft) −SL(t)
...(5) ΔSt'ft+Δ1)=α・ΔS
Lft) +β・[ΔSL(t)-ΔSt(t-ΔC
,)]SL' ft+Δt)= Stft+Δt)+
ΔS1′ft+Δt)...(7) Here, SL[) Actual total demand Slltl at two times: By season. By day of the week. Hourly. Total demand at time t ΔSt′ (tmo Δ1) statistically determined from past data classified and accumulated by weather: Total demand predicted value at time (t + Δ1) α, β: Calculated as above by coefficient The predicted total demand will be explained using Figure 2. If the actual total demand from time ΔC to t increases with respect to the total demand S1 statistically determined from past data, it is assumed that the actual total demand increases in the same way after Δt. You can. Therefore, (5) above. (6).
Equation (7) allows us to appropriately predict future total demand by Δt.

Next, the future system state prediction process S12 predicts the future system state in the following steps based on the current system state determined in process S10 and the total demand predicted in process S11! II.

The load power and generator output after Δt with respect to the current time t are determined as follows.

[SL' it+Δt)-SL(t) 3...(8
) QL. (t+Δt)=QL. (t) +PF
．． (t) [PL. (t+Δt)−PI. (
t)]...(9) PGj (t±Δt) is obtained by calculating the operation schedule and economic load distribution from the predicted total demand st'(t+Δ1). ...(10)VGj (t
+Δt): Obtained from the AVH operational standard value pattern. ...(11) Here, PL. (t+Δ1): Active power QL of load i at time tmoΔt. (t+Δ1): Reactive power PGJ of load i at time t+Δt (t±Δt): Active power VG of generator j at time t+Δt, (t+Δ↑): Voltage Prit of generator j at time t+Δt): Load i Power factor Sl at time t
it): Actual total demand SL' at time t
It+Δ[): Result of process S11 At this time, the power factor of the load uses a value statistically determined from past data that has been classified and accumulated by season, day of the week, and time.

The relationship between the above-mentioned total demand and time is shown in FIG.

Power flow calculations are performed using the above values as constraint conditions.

Next, the response of an independent control device such as an individual VQC is simulated and the capacitor is adjusted. The future state of voltage regulating equipment such as reactors and transformer taps is determined, and power flow calculations are performed again to obtain the final power system state data at the future time.

According to the embodiment described above, future total demand can be appropriately predicted, and appropriate data regarding voltage stability can be provided to the operator.

[Effect of the invention j As explained above, according to the present invention, future total demand is predicted by correcting statistical values of past data using current values, so that total demand does not suddenly increase. Not only does it accurately predict future total demand even when it is changing, it also appropriately predicts future grid conditions and provides the necessary amount of adjustment when adjustment is necessary, resulting in more stable power supply. It becomes possible to operate the grid.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the processing contents of the power system monitoring and control system according to the present invention, FIG. 2 is a relationship diagram between total demand and time, and FIG. 3 is a configuration diagram of the power system monitoring and control system.
FIG. 4 is a flowchart showing the contents of conventional processing. S10... Grid state determination processing S11... Total demand prediction processing S12... Future grid state prediction processing S30... Stability limit calculation processing S40... Stability monitoring processing S50... Effect size calculation processing St30...Adjustment amount calculation processing S70...Output processing

Claims (1)

[Claims] A system state determination means that determines the state of the power system, which is composed of an information transmission device, an electronic computer, and a man-machine interface device; a future system state prediction means that predicts the future system state from the current system state; a stability limit calculation means for determining a voltage stability limit for a future voltage stability limit; a stability monitoring means for determining a future degree of grid voltage stability from a future voltage stability limit; an effect amount calculation means for determining an effect amount for increasing the voltage stability of the improving means; an adjustment amount calculation means for calculating an adjustment amount necessary to stabilize the future grid voltage when it is unstable;
In a power system monitoring and control device having an output means for presenting various data to an operator and for giving an alarm to that effect when the stability of the system voltage is insufficient or the system voltage is unstable, A total demand forecasting means is interposed after the determining means to detect the difference between the actual total demand and the total demand statistically calculated from past accumulated data and the rate of change in the difference, and to calculate the difference statistically based on this difference and the rate of change. An electric power system monitoring and control system that calculates future predicted total demand by correcting the determined total demand, and predicts future system status using the corrected predicted total demand.