JPS6151496B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power system stabilizing device, and particularly to a power system stabilizing device that is equipped with an accident type discrimination function and that appropriately and promptly controls various system stabilizing devices in consideration of the system operating state. The present invention relates to a control device for a stabilizing device.

As power system stabilization devices, as is well known, high-speed valve control devices (hereinafter referred to as EVA control devices),
Braking resistance control device (hereinafter referred to as SDR control device),
Forced excitation control device, power suppression control device (hereinafter referred to as GS)
(hereinafter referred to as control device) and system stabilization device (hereinafter referred to as PSS)
devices) are known.

All of these devices are control devices designed to ensure a stable supply of power even in the event of a system failure, system operation changeover, or even in the event of a slight disturbance in the system.The following is a brief description of each control device. The control details will be explained.

In a power system, power supply and power consumption are balanced during steady state, and the power system operates stably at a roughly constant frequency while maintaining synchronization with each other. However, if an accident such as a 1-wire ground fault, 2-wire ground fault, or 3-wire ground fault occurs in the grid, the balance between power supply and demand will be significantly disrupted, and the generator on the power supply side will accelerate significantly unless appropriate control is applied. Even after the accident point was removed, synchronization could not be maintained, leading to loss of synchronization.

For this reason, it is possible to reduce mechanical input using EVA control, force load application using SDR control, limit the power supply using GS control, or suddenly increase the generator's excitation to increase rotation. Control is performed to eliminate imbalances in power supply and demand to prevent synchronization.

The above is a stabilizing device aimed at improving so-called transient stability, but even if transient stability is achieved in the next step, that is, even if the first wave of power fluctuation is pulled back and no step-out occurs, Continued shaking can cause vibrations to dissipate, leading to loss of synchronization. To deal with this, the damping constant of the system can be increased by installing a PSS device.
The aim is to quickly suppress oscillations and improve dynamic stability.

By the way, among these system stabilization devices, the forced excitation control and PSS device have the property of automatically operating and being controlled in the event of a system abnormality, but the remaining SDR control, EVA control, and GS control In this case, it is necessary to detect a system abnormality and to manually start one of the controls or a combination of controls only when the abnormality occurs.

However, until now, these latter three types of control devices have only been used as control devices for system stabilization, and the effectiveness of each type of control device has been verified individually under the same conditions. Currently, important factors such as efficient system operation and practical operation methods are not taken into account. Therefore, it would be very meaningful to have an integrated control device that can appropriately separate and control these three types of control devices based on the accident type, operating status, plant configuration, etc.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to unify various system stabilizing devices and use them properly in consideration of the system operation status, so that the various system stabilizing devices can be used appropriately. It is an object of the present invention to provide a control device for a power system stabilizing device that can perform quick control.

An embodiment of the present invention will be explained below with reference to the drawings. FIG. 1 shows in block form an example of the configuration of the present invention. In FIG. 1, numerals 1 to 4 indicate external signals input to the present device, that is, an external relay output, a secondary output of an instrument transformer, a system operation status signal, and other status quantity signals, respectively. External relay output 1 is a contact output when the protection relay and the control relay operate due to a change in the state amount that occurs due to an accident on the grid side or a change in the system operation state. The secondary output 2 of the instrument transformer is the secondary output (analog quantity) of the instrument transformer (current transformer) on the system side and the generator side. The system operation status signal is a contact output for grasping the system configuration and operation status through contacts such as disconnectors, disconnectors, etc., and other status quantity signals 4 include phase angle, rotation speed, etc. other than the above as necessary. It is a state quantity signal. On the other hand, numeral 5 designates a control device for a power system stabilizing device to which each of these external signals 1 to 4 is input, and is configured as follows.

The fault type determination circuit 6 is a circuit for determining the type of fault occurring in the system, and inputs the external relay output 1 and the secondary output 2 of the instrument transformer, and outputs the reference signal generation circuit 7.
The type of accident is determined by detecting how the analog quantity due to the occurrence of the accident has changed from the steady state using the basic signal from the system. The system status determination circuit 8 is the secondary output (analog signal) of the instrument transformer.
2 and system operation status signals (digital signals) to determine the information on the system operation status and power transmission power status before the accident, and at the same time determine changes in the system operation status such as one line being opened when there is no accident. . The control content determination command circuit 9 selects the control content according to a preset pattern based on the input from the accident type determination circuit 6 and the system status determination circuit 8, and instructs the controlled object, which is an operation, to start control. It is. Reset circuit and pattern program circuit 1
0 confirms that the other state quantity signals 4 have returned to normal after an operation command is issued by the control content determination/command circuit 9, or resets the operation end according to a time-series patterned program. Instruct the timing to the control content determination/command circuit 9,
Further, at a certain timing after an accident occurs, a reset signal is sent to the accident type determination circuit 6 and the system status determination circuit 8 in order to determine whether the re-closing is successful or unsuccessful. The operation circuit 11 is for starting or stopping EVA control, and the operation circuit 12 is for starting or stopping EVA control.
This allows GS control to be performed. Operation circuit 13
is for performing the second GS control, and the operation circuit 14 is for starting or stopping the SDR control. All of these control objects are operated by commands from the control content determination/command circuit 9.

Next, to describe the operation of the present device, first, an example of a control pattern will be explained in order to facilitate understanding. Figure 2 shows a typical example of the control contents that are operated in the event of a system accident.The upper part divided by dotted lines shows the processing contents at the time of the accident in chronological order as an example, and the time when the system accident occurs is t ₀ 0, t ₅
Accident point removed at time (0.1 seconds after t ₀ ), t _8
SDR input or
GS control, reclose at t ₂₆ (0.52 seconds after t ₀ ), break due to failure of reclosure at t ₃₁ (0.62 seconds after t ₀ ), and break at t ₃₄ (0.62 seconds after t ₀₎ as 0.68
This shows the timing at which SDR control is turned off and GS control is performed (seconds later). This content is designed so that the operation content is a sufficient condition for all cases, but there are some operations that are unnecessary in each case. Note that T (between t ₅ and t ₂₆ ) indicates the no-voltage time.

In addition, the lower part divided by dotted lines shows the contents of the control items at each point in time mentioned above in more detail.
Two transmission lines are in operation, two or more generators are in operation, and two
This is based on the assumption that reclosing will not be performed and EVA control will not be performed in the event of a line-to-ground fault (hereinafter abbreviated as 2LG) or a three-wire fault (hereinafter abbreviated as 3LG). In other words, accident type A indicates the accident type during two-line operation, and assuming that both the first and second lines have the same impedance and are connected to the same bus at the beginning and end, the combination of accident types is as shown in the figure. This results in 9 cases. In addition,
In addition to this, a case of single-line operation may also be considered, but it will be omitted here. For fault point removal B, in the case of a 1-line ground fault (hereinafter abbreviated as 1LG), one phase of the fault phase is disconnected (hereinafter abbreviated as 1LO) in order to reclose the circuit, and in the case of 2LG and 3LG, the circuit is reclosed. To prevent this, the 3-phase fault line was disconnected (hereinafter abbreviated as 3LO). SDR input or GS control In the case of SDR input control, SDR is input uniformly, and in the case of GS control, the stability of the system is examined and control is performed according to the required GS amount. Note that the GS amount varies depending on the operating status of each plant, but for ease of understanding, it is shown here as "1" when GS control is implemented and "0" when GS control is not implemented. Reclosing circuit D is 1
This is carried out only in the case of LO, but if it is successful, it will move directly to SDR removal control F, and if it fails to reclose, it will move to SDR removal control E, and then continue.
The process moves to SDR exclusion control and GS control F, and the series of stabilization control device controls ends. The amount of GS at the time of failure in reclosing is displayed as "1" or "0" for the same reason as mentioned above, and at the same time, it is displayed in parentheses to distinguish it from the time when reclosing is successful.

These series of control contents are determined by conducting stability analysis in advance for each accident type, system operation status, power transmission capacity before the accident, and each case of successful reclosing and failure, and the necessary GS amount if stability is maintained. , SDR ON/OFF timing, and GS control timing, and by memorizing these in advance in the control content discrimination/command circuit 9 shown in Figure 1, simple logical judgment and Time-series control enables prompt, error-free and efficient operation of a series of system stabilizers.

Next, the operation of the present device will be described by taking an example from among the control patterns described above. Figure 3 is a flowchart showing the operation based on an example of the control pattern.
There is a case of LG, 2 lines 1 LG. Now, the grid operation status signal 3 and the secondary output of the instrument transformer 2
is input to the system status determination circuit 8, and the system status determination circuit 8 determines that the power transmission system is in operation with two circuits, the maximum capacity of the transmission power before the accident, and the number of operating generators are, for example, two. It is assumed that a signal is applied to the control content determination/command circuit 9. In such a situation, if an accident occurs in the power system on line 1 LG and line 2 3 LG, the external relay output 1 and instrument transformer output 2 at that time will be
In response to the input of the next output 2, the accident type discrimination circuit 6 discriminates the type of system accident and provides the discrimination signal to the control content discrimination command circuit 9. Then, in control content determination/command time 9, the control mode in this case is instantaneously selected, commands are immediately given to operation circuits 12 to 14, SDR input control and GS-1 control are performed and activated, and one unit is activated. Performs GS control of the generator. After such control is performed, when the scheduled time has elapsed, the reset circuit and pattern program circuit 1
A reset signal is sent from 0 to the accident type discriminating circuit 6 and the system status discriminating circuit 8, and both discriminating circuits 6 and 8 are reset. Here, the control content determination/command circuit 9 checks whether or not the re-closing has been successful based on the state of the determination signals from both the discriminating circuits 6 and 8 after the reset, and if the re-closing is confirmed to be successful, the operation path 14
A command is given to SDR off control.

The above has taken up one example of the control mode and described its operation, but in reality it is
The command circuit 9 has various control modes built-in as shown in Fig. 2, and the system stabilization device can be controlled in the control mode corresponding to the system operation status in other cases or in response to system accidents. Control can be performed appropriately and quickly.

In the above embodiment, the explanation has mainly focused on measures against transient stability, but if the power system has severe dynamic stability, even if one line is opened without an accident, it may go out of synch. Incorporating a pattern in which EVA control is performed simultaneously with opening into the control content determination/command circuit 9 provides a great advantage in terms of system operation. In addition, if the power transmission capacity is equivalent to a partial load, the control content command determination/command circuit 9 ranks the power transmission capacity range and classifies it into about four patterns, and performs the corresponding GS control. By omitting this, complication of control can be avoided. Furthermore, although EVA control is not mentioned in Figure 2, EVA control is a desirable method for system operation among system stabilization devices, and it is desirable to incorporate it into the control pattern with priority over SDR control and GS control. .

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

As described above, according to the present invention, the system stability is maintained by analyzing the transient stability and dynamic stability in advance by inputting the system fault state, pre-fault system operating state, number of generators, etc. We created a pattern for operating procedures when a system accident occurs, and automatically select the appropriate operating procedure pattern based on the data input at the time of a system accident, so we can effectively and quickly integrate various system stabilization devices A control device for a power system stabilizing device that can be controlled can be provided.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of a control device for a power system stabilizing device according to the present invention, and Fig. 2 shows a typical example of a control pattern built into the control content determination/command circuit in the same embodiment. FIG. 3 is a flow chart showing an operation based on an example of the control pattern shown in FIG. 2. 6... Accident type discrimination circuit, 8... System status discrimination circuit, 9... Control content discrimination/command circuit, 10...
Reset circuit and pattern program circuit, 11
~14... Operation circuit for operating various system stabilizing devices.

Claims (1)

[Claims] 1. A first device that determines the type of accident based on the input of the output signal of the protection and control device that responds to changes in the amount of electricity in the system at the time of a system accident and changes in the system operation status associated with this, and system configuration and generator operation. a second device that inputs a system operation status signal according to the number of systems and determines a system state that affects system stability; The operating procedures of various system stabilizing devices for maintaining system stability when a system condition that affects the system stability determined by the second device is patterned and built-in are prepared in advance, and the first When the device determines the type of accident in the system and the second device determines the system state that affects the transient stability of the system, a pattern of operation procedures corresponding to the accident type and system state is selected to stabilize the various systems. A control device for a power system stabilizing device, comprising a third device that collectively controls the device.