JPS6258225B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load selection and disconnection device for a power receiving and distribution system, which promptly and optimally disconnects a load in the event of an accident.

In a power receiving and distributing system as shown in Fig. 1, in which a large number of power supply systems connecting multiple loads are connected to each other, if an accident in the power receiving system or a failure or accident in the generator 32 occurs, the load balance of the power supply capacity will be affected. Power receiving system 31 and generator 32 that have not collapsed or failed
may become overloaded. In such a case, if left untreated, the power will trip one after another and develop into a total power outage.

In order to avoid this, when a failure occurs on the power supply side, the load 33 that matches the supply amount of the failed power supply is cut off, and a load selection is made to maintain a balance between the power supply capacity and the load capacity after the failure occurs. A break may be provided. This load selection and disconnection device is as described below, and in the past, as a method for load selection and disconnection, a pin board was widely used. In this method, trip causes on the power supply side (hereinafter referred to as failure causes) and load systems are arranged on a matrix on the operation desk, and specified on a pin board. Recently, many decisions and commands that used to be made manually are now being made by computers. That is, when an accident occurs, a computer is used to determine the power supply capacity on the accident side and the necessary or disconnected capacity to meet this capacity, calculate the load balance and load priority, and issue a selection command.

FIG. 2 is a circuit diagram of the pin board.
A ₁ , A ₂ , . . . A _o are contacts that open and close depending on the cause of failure on the power supply side, and are activated when a failure occurs in the power system 31 or generator 32 shown in FIG. 1. Also
B ₁ , B ₂ , . . . B _n are simulated load systems provided corresponding to the actual load systems. Next, Cij(i=1
~n, j = 1 ~ m (where n, m are positive integers) is a contact that determines which load is selected or disconnected depending on the cause of the failure of the power supply, and is opened or closed by inserting a pin into the pin board. . On the other hand, 1R, 2R, and mR are relays that give a shedding command to the relevant load in the event of a failure. Due to the operation of this relay, D ₁ , D ₂ ,
...opens and closes the contacts of D _n , and the circuit breakers CB ₁ , CB ₂ ,...
...to cut off CB _n . FIG. 3 is a circuit diagram of a conventional load selection and disconnection method using a computer 50. _E1 ,
E ₂ , . . . E _o are relays for giving a shedding command to the load selected by the computer 50.

In the case of the conventional load selection and disconnection device as described above using a pin board, there is a risk of errors, disconnections, shortages, or disconnections if pin selection is not performed appropriately. Even when a computer is used, there is a delay in the calculation time and command output in principle, so there is a risk that it will not be in time even if the calculation is performed after a failure occurs and a load or disconnection command is issued.

The purpose of the present invention is to always select the optimum load-off state before a failure occurs, to quickly turn off the optimum load when a failure occurs, and to prevent subsequent failures even when failures occur one after another. The object of the present invention is to obtain a load shedding device which can select an optimum shearing state and shear the load without causing a complete stoppage.

Embodiments of the present invention will be described below with reference to FIGS. 4 and 5. FIG. 4 shows a circuit diagram of the invention. Contacts F ₁ ...F _o and G ₁ ...G _o are assembled by a protective relay or sequence that detects faults that occur on the power supply side, such as power input/output, generator overload, generator trip, etc. Contacts F ₁ , F ₂ , . . . , F _o are instantaneously closed when an accident occurs in the power supply. This contact operates only once after the first accident occurs, and does not operate in the event of a second or subsequent accident. Contacts G ₁ , G ₂ , . . . G _o do not operate immediately even if an accident occurs in the power supply, but close after a certain period of time has elapsed. These Gi and Fi contacts operate in response to a failure signal. contact
Ci,j (i = 1 to n, j = 1 to m) is the output Ei,j of the computer that selects the load that should be cut off, calculated by the computer based on the cause of failure, load balance, and load priority. (i=1 to n, j=1 to m).

G ₁ ...G _o is used to change the selection of the accident feeder until the internal load priority calculation is completed even if the accident feeder F operates. Shiyadan feeder
Cig is the choice for accident feeder 1 line.
Even if two feeders are selected at the same time, if there is a common feeder Cig for the two accidental feeders, the feeder will be short by this amount. In the case of the second accident, it is necessary to select the shingle cutting feeder again, and if the maximum efficiency point is determined at this time, there is a possibility that a shingle cutting feeder different from the initially set one will be selected. G ₁ ...G _o has a time limit element to allow time to select a new feeder or cut feeder in response to the second accident, and has the role of preventing shortages or cuts or errors or cuts.

In the operation of the contacts F ₁ ...F _o and G ₁ ...G _o , if up to the third accident occurs simultaneously, the contacts of G ₁ ...G _o will
Regarding the third accident, there is a possibility that the contact points of G ₁ ... G _o operate simultaneously, but as long as the device of the present invention prevents chain accidents, it is extremely unlikely that three or more power supplies will fail at the same time. This is a rare case, and the second
If accidents can be prevented, the purpose of this device can be fully achieved.

B ₁ , B ₂ , ...B _n is the load system, A ₁ , A ₂ , ...A
_o indicates the cause of failure and other symbols are the same as those shown in the conventional example. The operation of the computer 50 is shown in FIG. The computer 50 takes in the power used by the load system and calculates the balance between the capacity of the power receiving system, the capacity of the generator, and the load based on the importance of the load specified separately, conditions such as power interruption, etc. Based on this, the priority of the load to be shelved is determined.

The computer 50 reads each supplied power and the power used by each load at regular intervals, calculates load balance and shearing priority, and determines which load should be used for each failure cause A ₁ , A ₂ , . . . A _o. Decide if it should be terminated. To calculate the load failure pattern, select any feeder from among the load feeders, select any feeder from among the feeders that can be disconnected, add up the load capacity, and calculate the load failure pattern of the feeder that is close to the amount of power that cannot be supplied. Find a combination. In addition, in the event of an accident, the priority order for shunting is calculated and set again from the remaining power source and load. A priority is set for the load feeders, and a high priority is set for the feeder that must be loaded or cut off, so that the feeder remains loaded and uncut until the end.

Next, the operation of the load selection and disconnection device will be explained using an example in which the first failure cause is A _and the primary failure occurs at _A2 . If an accident occurs in the power system,
The fault signal closes contacts F ₁ and G ₁ and is input to the computer. Since the contact F ₁ is closed instantly after the occurrence of an accident, _the excitation coil is turned on through the contacts set to C ₁₁ , C ₁₂ , . This excitation causes the load to be quickly disconnected.

The computer 50 receives the accident occurrence signal at the same time, and determines the priority order for stopping the remaining power supplies other than the A system from the remaining load feeders in the event of a failure of each power source, and also determines the priority order of shutdown in the event of a failure of each power source, and also outputs the remaining power supplies other than the A system _{to the remaining load} feeders. Other except _1n
The calculation result is set at the contact point of Ci,j (i=2 to n, j=1 to m). Even if a second power supply failure occurs during this time, F ₁ will remain in operation due to the first failure, so F ₂ will remain active until all contacts Ci and j have been set.
does not operate, and the cause contact _G2 is on delay, so no load or disconnection signal is output. Contact point Ci,
After all settings of j are completed, the delay of the cause contact _G2 is melted and the load due to the second cause is quickly cut off. In the present invention, the latest load balance calculation results are always set, unlike the conventional system which calculates and outputs the results after a failure occurs, so it is possible to respond instantly when a failure occurs. Therefore, chain reactions caused by delays in calculations, etc. can be prevented. Even if failures or accidents occur one after another, preparations for the next failure or accident can be made promptly, making it possible to minimize the impact on subsequent failures or accidents.

By using the load selection and disconnection device of the present invention as described above, it is possible to obtain a load selection and disconnection device with higher reliability.

[Brief explanation of the drawing]

Figure 1 is a system diagram of power reception and distribution, Figures 2 and 3 are circuit diagrams of conventional load shield disconnectors, Figure 4 is a circuit diagram of the load shield disconnector of the present invention, and Figure 5 is a circuit diagram of the present invention. 3 is a flowchart showing the operation of the invention. 30...Internal busbar, 31...Power receiving system, 32...Generator, 33...Load, A...Fault signal, B...Load system,
CB...Shipping breaker, F...Momentary contact, G...Time-limited contact.

Claims (1)

[Claims] 1 A power receiving and distribution system that supplies electric power supplied from an electric power system and electric power from a generator to multiple loads with priority orders of importance, and in the event of an accident in the system or a failure of the generator, the multiple loads are In a device that cuts off the load based on a set priority, a contact is provided that instantly responds to a fault signal, and the operation of this contact selects and cuts off the load corresponding to the fault, and the selected load is cut off. Based on the load and power supply after the power failure, a time-limited contact is provided that operates for a time period during which a computer calculates the selection of the load to be selected in the event that a power failure occurs in this state. A load selection/disconnection device characterized in that when a system failure occurs while an instantaneous contact is operating, the load is selected or disconnected by operating the time-limited contact.