JPS6392229A - Method of stabilizing power system - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention stabilizes the power system by determining whether or not the generator is under tax control when an accident occurs in the power system, and when it is determined that the power system is unstable, by shutting off the water pump. This article relates to a power system stabilization method that maintains energy efficiency.

[Conventional technology]

Figure 1 is a system diagram of a conventional power system stabilization method using pumped storage cutoff, as shown in, for example, Japanese Patent Application No. 60-53610.
The embodiment of the present invention is also applied to the stabilization control shown in the figure, as will be described later. In the figure, 1 is a pumped storage (generator) that is subject to cutoff control, 2 is a generator that supplies power to the grid, 6 is a pumped storage load that is pumped up to the upper dam by the pumping operation of pumped storage device 1, and 4 is the generator. 2 is a boiler turbine for driving the water pump 1, 5 is a breaker on the side of the water pump 1, 6 is a transformer, and 7 is a bus bar on the pumping side. tfc, 8a.

8b are pumping lines IL and 2L that send power to the pumping machine 1.

9a, 9bH water pumping line 8a, sb breaker, 10a.

10b is a current transformer that measures the pumping line current; 11 is a transformer that measures the voltage of the pumping side bus 7; 12a and 12b are the current transformers I Da and 1 ob and the transformer 11 (the current transformer and An instantaneous power converter outputs the power value of each pumping line 8a, 8b from the current and voltage from the transformer (referred to as power monitoring means), 16 is a transmission terminal device that transmits the generator power to the pumping side, 14F'i A transmission terminal device that receives data on the pumping side, 15 a microwave transmission route, and 16 a pumping end control terminal device that performs a step-out determination calculation based on the pumping power received at the pumping end and the transmitted generator power. , 17 indicates a shutdown command), and 18 indicates an electric power system to which the generator 2 and the water pump 1 are connected.

Next, the operation will be explained. First, a description will be given according to a flowchart showing the control sequence shown in FIG.

First, there are various calculation methods for determining step-out of the generator 2, but here we calculate the phase angle θ from the equation of motion of the rotating machine and determine whether or not the generator step-out occurs by determining whether or not the phase angle θ exceeds a critical value. This will be explained in terms of the method of discrimination. Hereinafter, G indicates various quantities on the generator side, and L indicates various quantities on the pumping machine side.

First, an interrupt is generated every calculation cycle to execute the next calculation. That is, in (S-1), the number of operating initial water pumps before the accident is always taken. Subsequently, in (S-2), power data at a predetermined measurement point A is taken in at its own end. At this time, the pumping lines 8a, s that send power to the pumping machine 1
The various amounts on the pump side of b are also taken in. Moreover, after receiving the power data from the measurement point 5-3), the process moves to the calculation of the initial phase angle θ for the first time (S-4).

(1) It is balanced with i before the accident, PC input) = P (output), and it is calculated as the amount of pumped water (= PL (output)) = total received power before the accident (= PL (input)). , the initial number of units in operation on the pumping side is also determined.

(2) Next, when the power value drops by more than a set value from the pre-fault value, the occurrence of an fault is detected (S-5).

If it is established, the detection of the accident is confirmed, and the pre-accident value po at that time
(t(00mB), Pl-(t-100m+3
) are Pa et +, Pt, (0+ and fixed (S-
6).

(3) Once the accident occurrence detection is confirmed, calculate the momentary phase difference θ(1) after the accident occurrence as θ0: initial phase difference (S
-7).

(4) Stable critical value θ until calculation termination time. Compare θ(1) with 5-8), θ. If ≦θ(11), it is determined that it is unstable, and a pumping cut-off calculation is performed, the control amount is calculated, and system stabilization control is performed (S-9). Also, if θ.>θ(1), it is determined that it is stable, and the following The check for instability is repeated every calculation cycle (S-10).

Next, Figure 4 shows an example of power change in a system fault other than the pumping lines 8a and sb.
Pumper power Pdt) also fluctuates roughly following the fluctuations in t), but in the case of a pumping line accident, as in the examples in Figures 5 and 6, the amount of water pumped differs from the actual pumped water. Pumping machine power PL (t)
occurs, making the power system unstable. In other words, in the example shown in Fig. 5, if the pumping line accident does not cause the pumping line to be released when 1L is opened, the control device misrecognizes the actual pumping amount R by the shaded pumping amount S1. As a result, the pump power (t) is evaluated unstable.

In addition, FIG. 6 shows that when 1L is opened at the time of a pumping edge accident and pumped water is decoupled, the stabilizing effect S2 due to decoupling can be evaluated, and the corrected pumped water amount R2U is lowered. Here, area A is when the number of operating pumps is (nl+n2), area B is when 1L of pumps is opened and the pumping disassembly is performed, and area C is when the number of operating pumps is n3. It is. Further, tI indicates the time when an accident occurs, and tti indicates the time when the accident is removed.

[Problem that the invention seeks to solve]

Conventional power system stabilization systems are configured as described above, so there is no problem with system accidents like the one shown in Figure 4.
In the case of a pumping-edge accident like the one shown in the figure (Figure 6), the disconnection of the pumps due to the opening of the transmission line is not taken into account, so the decrease in received power due to the disconnection is taken in as is, whereas in Figure 1 ◆ Since the breaker 5 on the pumping side, which is monitoring the stoppage, is not opened and the breaker 9a or 119a on the power line side is released, changes in the number of pumping units in operation are not taken into account. Inside P
μt) becomes a small value, and θL (<0) is overestimated. That is, U(1)=θo(1)−〇, (tl
Ten. , θ (tl becomes large, and even though in reality only the pumped hydrolysis train has a considerable stabilizing effect, θ is determined to be on the unstable side. There were some problems, such as getting stuck.

This invention was made in order to solve the above-mentioned problems, and it is a power system that determines whether a pumped-storage line is disconnected due to a pumping edge accident, evaluates the resulting stabilizing effect on the power system, and prevents excessive control. The purpose is to obtain a stabilization method.

[Means for solving problems]

In the power system stabilization method according to the present invention, the pumping section power is monitored, and if the power is not restored even after the fault has been removed, it is determined that an fault has occurred in that pumping line and the pumping machine has been disconnected as the fault is removed. However, even if the breaker on the pump side is not opened, the number of pumping units in operation is adjusted appropriately to prevent excessive control while evaluating the stabilizing effect of the parallel pumps.

[Effect]

In this invention, the stoppage of the storage pump is recognized by incorporating the open/closed state of the circuit breaker shown in Figure 1, but if the circuit breaker on the transmission line side is opened due to a pumping edge accident, the storage pump will be disconnected from the system. However, the circuit breaker is not opened sequentially until much later. Therefore, we checked the power of the pumping line when the accident was removed, and determined that the pumping line where the power had not been restored despite the detection of the accident removal had been opened, and the number of operating pumping units connected to that pumping line was initialized. Subtract it from the number of operating units to correctly recognize the number of pumping units in operation after the pumping-storage line is disassembled.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

As mentioned at the beginning, the construction of the device itself is the same as that of the prior art shown in FIG. 1, so the main parts will be explained with reference to the prior art section. FIG. 2 is a flowchart of the system stabilization method according to the present invention.

Next, the operation shown in FIG. 1 will be explained with reference to the flowchart shown in FIG. First, the initial number of operating pumps 1 before the accident is determined for each pumping line 8a, 8b, IL, and 2L ((S-
1). Let each of these be ni*n2. (S-1) to (
The operations up to S-5) are the same as those of the prior art.

40rns after accident removal detection, pumping lines 8a, 8bIL
, check the power value of 2L, and if the pumping section power is 20% of the capacity of the single pump, it will be determined that it is a pumping-related accident.5-8)
The pumps connected to that pumping line are considered to have been disconnected from the system.

Next, a step-out determination calculation is performed to determine the presence or absence of step-out. At this time, for example, when using the phase angle, (nt+nt)ΔP=P
L(0)-PL(t) M=(n++nz)”z
(S-9, 10) oHere, if the 1L side of the storage pump is opened due to an accident (however, pL"(t) l'j, the momentary power for nm units, θ゛ is the time of accident removal. (phase angle of Mechanical output (= pumped water = pre-accident power) to (n++n,) units → n
I need to fix it to t level.

The integrated phase angle calculation value θ is compared with a stability critical value (180°, etc.) to determine whether there is a tax adjustment (system instability phenomenon) (
S-11) When determining instability, perform pumping cutoff control (S-11)
-12), when determining stability, the comparison with the stability critical value is repeated 9 times until the calculation abort time.

In the above example, an example was explained in which the phase angle is used to determine the presence or absence of out-of-step. However, if the pumping side angle has the same tendency, the system is out-of-step (unstable), and if it is in a convergence tendency, the system is stable. There is also a method of determining stability as described above, and it is also possible to perform appropriate tax adjustment determination by correcting and calculating Δω1 in accordance with the pumping and disassembly sequence.

〔Effect of the invention〕

As described above, according to the present invention, by monitoring each pumping linear force value, it is possible to determine the pumping line failure caused by a pumping line accident, and to evaluate the stabilizing effect of only the resulting pumping line accident, thereby preventing excessive shutoff. This has the effect of providing appropriate control for stabilizing the power system. Furthermore, since the pumping line power as an input value is used, there is no need to provide any special equipment or input for identifying pumping line accidents, and the device can be constructed at low cost.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram when a system stabilizing device according to an embodiment of the present invention is applied to an electric power system, Fig. 2 is a flowchart showing the control sequence of the present invention, and Fig. 3 shows the control sequence of the conventional technology. Flowchart, Figure 4 is a characteristic diagram showing an example of power change in a system accident other than a pumping line, and Figures 5 and 6 are characteristic diagrams showing an example of power change in a pumping line accident. Pumped storage (generator) generator, 2? I machine, 5 is a breaker, 6 is a transformer, 7 is a bus bar, 8a, 8b are pumping lines, 9a, 9b are breakers (of the pumping lines), 10a, 10b
11 is a transformer, 16 is a pumping end control terminal device,
17 is a cutoff command route, and 18 is a power system. Patent applicant Mitsubishi Electric Corporation Maki 2 Figure 3

Claims (1)

[Claims] In order to stabilize the power system, a system stabilizing device such as a transmission line breaker or a water pump breaker is provided, and in the event of a system accident, the breaker is released as appropriate to stabilize the system. In the power system stabilization method described above, the power of the pumping line connected to the power system is taken in, the power of the pumping machine is monitored by a power monitoring means, and in the event of an accident in the pumping line, a breaker on the power transmission line side is released, and the Immediately after the breaker on the power transmission line side is released, the power of the pumping line is checked by the power monitoring means, and if the power is not restored even though fault removal detection has been performed, the pumping end determines that the pumping line has been released. The control terminal device determines the number of operating pumping machines connected to the pumping line, and properly recognizes the number of operating pumping machines after the pumping line is disassembled to prevent excessive control. Power system stabilization method. (2) As a step-out determination calculation method in the pumping end control terminal device, the pump side angular frequency and the generator side angular frequency are determined, and if the difference between the two tends to diverge, the system is unstable, and if the difference tends to converge, the system is stable. The power system stabilization method according to claim 1, characterized in that the power system is determined.