JPS60128830A - Load selection breaking unit - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a power system that supplies power to a load group from a power purchase system and a private power generation system that are operated in parallel, and in particular, to provide detailed load control according to the system operation status. The present invention relates to a load selective cutoff device that can perform cutoff.

[Technical background of the invention]

In recent years, in electric power systems, in order to ensure highly reliable power supply to load groups, power purchasing systems and private power generation systems have been operated in parallel.

FIG. 1 shows an example of the configuration of this type of power system. In the figure, 1 and 2 are transformers No. 1 and No. 2, and their primary side is connected via transformer primary circuit breakers 3 and 4, and further through power purchase system circuit breaker 5 and power purchase system circuit breaker 6. It is connected to a power transmission line (not shown). On the other hand, 7 and 8 are private generators No. 1 and No. 2, the output ends of which are respectively connected to bus bars 11 and 12 via generator circuit breakers 9 and 10.

Further, the secondary side of the No. 1 and No. 2 transformers 1 and 2 is connected to the busbar disconnector 19. 20 to the busbar 11 and via busbar disconnectors 21, 22 to the busbar 12, respectively. Furthermore, the bus bar 11
12 are interconnected by bus disconnectors 23 and 24, and a first load group 26 is connected between each of these disconnectors 23 and 24 via a load group breaker 25. Furthermore, second and third load groups 29 and 30 are connected between the transformer secondary circuit breakers 13 and 14 and the grid circuit breakers 15 and 16 via load group circuit breakers 27 and 28. has been done. In the figure, . and - represent a closed state, and port 01 represents an open state, respectively. Also,
Each of the load groups 26.29.30 is composed of a plurality of loads.

Now, in this configuration, while the power purchase system and the private power generation system are operating in parallel to supply power to each load group 26, 29, 30, a failure occurs in a particular piece of equipment and a trip occurs. In some cases, load cutoff A is performed by tripping individual equipment predetermined by a sequence circuit (not shown).
? Load shedding is performed based on turns to avoid secondary ripple power outages in the grid. In other words, for example, now 1
When a failure occurs in the No. 1 transformer 1 and its primary breaker 3 is tripped, the load group breaker 27 connected to the failed equipment is disconnected and the second load group 29 is disconnected. I try to do that.

[Problems with background technology]

However, in this case) load shedding is performed based on the load shedding pattern without taking into account the current load capacity at the time of IJ, f occurrence, so in some cases even though there is surplus power, more than necessary power is used. I cut off the load,
There is a risk that the suspension of the load operation will have a negative impact on factory operations, etc.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned problems, and its purpose is to perform necessary and sufficient load shedding according to the grid connection status, minimize the impact on the operation under the grid, and It is an object of the present invention to provide a load selection breaker capable of preventing secondary spillover power outages.

[Summary of the invention]

In order to achieve the above object, in the present invention, when a trip failure occurs in the power system described above, the load is calculated by subtracting the holding capacity that can be covered by the remaining normal equipment from the full load power immediately before the trip under the trip system. The system is characterized in that the load is selectively cut off in accordance with the system operation status by sequentially cutting off the load according to the scheduled priority.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention shown in the drawings will be described.

FIG. 2 shows an example of the configuration when the present invention is applied to the power system shown in FIG. 1, and the same parts as in FIG. Now, I will only discuss the different parts.

In the figure, 31' is a load selection cutoff device of the present invention, and its measurement value input (analog amount) A
, status, and fault input (digital quantity) B are input, and an interruption output C is outputted to the power grid. Here, as the measured value input A, the purchased power which is the output of the No. 1 and No. 2 transformers 1 and 2, the No. 1 and No. 2 private generators 7
．． In-house power generation power, which is the power generation power in step 8, and each load power are manually generated, and the state and failure power B are inputs of circuit breaker and disconnector device operation (open, close) status inputs, and trip failure inputs (
relay output).

FIG. 3 shows a functional block diagram of an example of the configuration of the load selection cutoff device 31.

In the figure, 32 is an input processing means for inputting and processing the measured value input A, the state, and the faulty human power B at a constant cycle, and 33 is the input processing means for inputting the measured value input A, the state, and the faulty human power B input by this input processing means 32. The latest status input contents are sequentially updated and stored, and each control limit value of the above-mentioned No. 1 and No. 2 transformers 1.2 and No. 1 and No. 2 private generators 7 and 8 is stored in advance. It is a storage means for Here, the power supply pattern to each load group 26, 29, and 30 is determined in advance based on the combination of the operating state (open, closed) of the disconnector and the circuit breaker by the state human power B.

Further, 34 is a trip system search means for searching which equipment (transformer, private generator) is affected by the trip when a fault input (trip fault input) from the input processing means 32 is detected. be. 35 stores the full load power immediately before the trip under the trip system searched by the trip system search means 34 in the storage means 33.
This is load power calculation means that calculates based on the contents stored in the. 36 calculates the holding capacity (power amount) that can be covered by the remaining equipment (transformer, private generator) under the trip system searched by the trip system search means 34, based on the content stored in the storage means. This is a holding capacity calculation means.

Furthermore, 37 is an overload capacity calculation means for calculating an overload capacity based on the difference between the total load power calculated by the load power calculation means 35 and the holding capacity calculated by the holding capacity calculation means 36. . Based on the overload capacity calculated by the overload capacity calculation means 37, 38 performs a breaker according to a predetermined breaker priority from among the load groups under the trip system so that the breaker capacity corresponds to the overload capacity calculated by the overload capacity calculation means 37. This is a cutoff target determining means that determines the target load. Reference numeral 39 denotes an output processing means for outputting a cutoff output C for the load determined by the cutoff target determining means 38.

Next, the operation of the newly installed M31 when selecting a load having such a configuration will be described using the flowchart shown in FIG.

Currently, the measured value input A and the state human power B are inputted to the load selection cutoff device 31 from the power grid at a constant cycle via the input processing means 32, and the contents are sequentially updated and stored in the storage means 33. be done.

In such a state, if, for example, the No. 1 transformer 1 of the power system fails and its primary side breaker 3 is tripped, the output from the input processing means 32 at Stella f81.8:t in FIG. When the faulty human power B is detected, it is searched that the equipment affected by the trip is the No. 1 generator 7. Then, step S
3, the load power calculation means 35 calculates the total load power L immediately before the trip under the trip system from the contents of the storage means 33.
(here, the total load power of the second load group 29) is calculated.

Further, in step S4, the holding capacity calculation means 36 calculates the holding capacity LH (here, the control limit value of the No. 1 private generator 7) that can be covered by the remaining equipment under the trip system from the contents of the storage means 33. Furthermore, in Stella fs5, the overload capacity calculating means 32 calculates the overload capacity, which is the difference (L - LH) between the full load power and the holding capacity LH.
is calculated, and the breaking capacity (=Lc) is determined.

Next, the load to be cut off is determined by the cutoff target determining means 38 according to the scheduled cutoff priority from the load group under the trip system (in this case, the second load group 29), so that the above-mentioned cutoff capacity is determined. It is determined. That is, first, in step 71'S6, the initial value is set to 0, and in step S7, the fifth value is set to 0.
A load selection cutoff table such as 10- shown in the figure is searched for priority quantities from 0 to n. Next, Stella f88.89
Next, check whether the fifth load is in operation and the instruction from the operator is to allow shutoff. If this is appropriate, this first load is determined to be shut off, and if it is not appropriate, the next load is selected. Move to points.

Furthermore, step Sx0. In S11, the above-mentioned overload capacity L
The load capacity of the amount determined from c.

Based on the difference (L, -L,), the cutoff output of the load determined as the cutoff target is sent out as the cutoff output C via the output processing means 39, and the Stellar f812 moves to the next point. The above action is such that the overload capacity Lc is satisfied by the load cutoff in step 813 (
0) or until the search counter l becomes oversized, and when this state is reached, MT is performed in step 814.

By carrying out load shedding as described above, only the necessary and sufficient overload is cut off in consideration of the current load capacity of the grid, and unnecessary cutoffs under the grid can be avoided.

In addition, in the above, as the failure human power B, in addition to the relay output due to overcurrent detection, etc., a detection output due to serious failure detection, etc. can also be used.

Further, although the load power calculation was performed using the measured value input A from the grid, it may be a fixed value specific to the equipment. In this case, in combination with the usage status of this device (open/closed 9 running/stopped), the characteristic value may be used if it is closed or running, and 0 if it is open or stopped.

〔Effect of the invention〕

As explained above, according to the present invention, when a trip failure occurs in the grid, the load is calculated by subtracting the holding capacity that can be covered by the remaining normal equipment from the full load power immediately before the trip under the trip system to the scheduled overload capacity. Since the load is cut off sequentially according to the priority, necessary and sufficient load is cut off according to the system operation status, minimizing the impact on the operation under the grid, and reliably preventing secondary spillover power outages under the grid. An extremely reliable load selection and interruption device capable of doing this can be provided.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an electric power system consisting of a power purchasing system and a private power generation system, Fig. 2 is a block diagram showing an electric power system to which the present invention is applied, and Fig. 3 is a functional block diagram showing an embodiment of the present invention. FIG. 4, and FIG. 5 are a flow chart diagram and a table diagram for explaining the operation of the same embodiment. 1.2...Transformer, 3, 4, 5, 9, 10,
13゜74, 7's, Ie, J7,
J s, z 5r 27128... interrupter,
6.19.20.21.22゜23.24... New road equipment, 7.8... Private generator, 11.12... Bus bar, 2
6,29.30...Load group, 31...Load selection breaker, 32...Input processing means, 33...Storage means, 34...Trip system protection means, 35...Load power Calculation means, 36... Retention capacity calculation means, 31...
Overload capacity calculation means, 38... cutoff target determination means,
39...Output processing means. Figure 4 Triumph' St 4 S2 3 TonLc 55 i=Q S6 Sea 52''i'' S7 7-F;

Claims (1)

[Scope of Claims] In a power system that supplies power to a plurality of load groups by operating a power purchasing system having a transformer and a private power generation system having a private generator in parallel, the output of the transformer and the private power generator are operated in parallel. an input processing means for inputting and processing measured value inputs of power generation power, each load power, etc., operating status of circuit breakers, disconnecting switch equipment, states such as trip failures, and failure inputs at a constant cycle; and input processing means input by the input processing means. a storage means for sequentially updating and storing the latest contents of measured value inputs and status inputs, and storing in advance control limit values of the transformer and the first uncle generator; and when a failure input from the input processing means is detected; , a trip system search means for searching all the devices affected by the trip failure, and the contents of the storage means for storing the full load power immediately before the trip under the 1J, f system searched by the trip system search means. a load power calculation means that calculates the load power based on 1-; a storage capacity calculation means that calculates the storage capacity that can be covered by the remaining equipment under the trip system searched by the trip system search means based on the contents of the storage means; Overload capacity calculation means for calculating overload capacity from the difference between the full load power and the holding capacity; The device is equipped with a cutoff target determining means for determining a load to be cut off in accordance with a predetermined cutoff priority storage, and an output processing means for outputting a cutoff output for the target load determined by the cutoff target determining means. Features a load selection breaker.