JPH07322475A - Overcurrent relay and overcurrent protection system - Google Patents

Abstract

PURPOSE:To set operating characteristics for achieving protection cooperation simply and quickly with less labor. CONSTITUTION:The circuit voltage of a load protected by an upper overcurrent relay, the type of a time-limit element, a set current tap value, an operation time-delay dial value, the operation current value of an instantaneous element, and a CT ratio are input to an overcurrent relay 1. Also, the circuit voltage of a load protected by an own overcurrent relay, a load type, a load capacity, a load short-circuiting capacity, and the CT ratio are input. On the basis of the input information, a logic operation circuit 1d obtains operation characteristics setting values (the type of the time-limit element, a set current tap value, an operation time-limit dial value, the operation current value of the instantaneous element) achieving the protection cooperation with the upper overcurrent relay and displays them on a display 1g.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overcurrent relay arranged in a power distribution system and an overcurrent protection system including the overcurrent relay.

[0002]

2. Description of the Related Art An example of a protection coordination curve between overcurrent relays arranged in a power distribution system is shown in FIG. A curve C1 is an operating characteristic of the overcurrent relay at the power receiving point, and this operating characteristic is instructed by the electric power company because it is necessary to perform protective coordination with the distribution system of the electric power company. Curves C2 to C3 are operating characteristics of the overcurrent relay arranged in the power distribution system below the power receiving point. Since the power distribution system generally has a hierarchical structure, in order to prevent disconnection of the circuit breaker of the upper system due to an accident at the lower level of the hierarchy,
The operating characteristics of the lower overcurrent relay must be shorter than the operating characteristics of the upper overcurrent relay. The curve C
In FIG. 1, 20 is a time-limited element characteristic of the power receiving point, and 21 is an instantaneous element characteristic of the power receiving point. In the curves C2, C3 and C4, 22, 24 and 26 are time delay element characteristics lower than the power receiving point, and 23, 25 and 27 are instantaneous element characteristics lower than the power receiving point.

FIG. 7 shows an example of the operating characteristics of the time delay element of the overcurrent relay, in which the horizontal axis is a multiple of the set current value (hereinafter referred to as the set current tap value) and the vertical axis is the operating time.
Anti-time limit characteristic 32, strong anti-time limit characteristic 33, super anti-time limit characteristic 3
4, there are overcurrent relays with operating characteristics such as long-reverse time characteristic 31 and the type of load of the distribution system (transformer, motor,
It is necessary to select the characteristic curve according to the fuse, the main trunk of power distribution, etc.). Further, FIG. 8 is an example of the operation time setting of the anti-time limit characteristic 32. Here, by setting a dial value (operation time limit dial value), the operation characteristic curve moves up and down.

Conventionally, the setting of the operating characteristics of each overcurrent relay, which enables the protection coordination between the overcurrent relays in the power distribution system, has been performed as follows. That is, in the protection cooperation table of FIG. 6, the time delay element characteristic 20 and the instantaneous element characteristic 2 of the power receiving point are shown.
Write 1 and then from the type of load and load capacity and CT ratio (circuit current ratio) protected by the lower overcurrent relay,
Select the type of time delay element and set current tap value, and
Converted to the primary current value, the timed element characteristic 22 and the instantaneous element characteristic 23 are written in the protection cooperation table of FIG. At this time, the time delay element characteristic 20 and the instantaneous element 21 of the upper overcurrent relay
Check that setting to run at least 0.3 seconds faster than. In the same manner, write the operating characteristics of the time delay element and the instantaneous element of the lower overcurrent relays in order to the protection coordination table and confirm the setting repeatedly, and repeat each operation to enable protection coordination between overcurrent relays. Set the operating characteristics of the current relay. Humans perform all the work of setting the operation characteristics.

[0005]

As described above, in the prior art, the setting of the operating characteristics of each overcurrent relay, which enables the protection coordination among the overcurrent relays, is all done by human work, which is very troublesome. It took a lot of work. In particular, in a power distribution system that receives extra-high voltage, the number of overcurrent relays may be 100 or more, and it is necessary to take protective coordination between each of the overcurrent relays. That is, it is necessary to write the operating characteristics of 100 or more overcurrent relays in the protection cooperation table to determine it, and then manually set the operation characteristics according to this protection cooperation table, which requires an excessive amount of labor.

The present invention has been made to solve such a problem, and an object of the present invention is to easily and quickly set the operating characteristics for enabling protection cooperation with a small amount of labor. An object is to provide an overcurrent relay and an overcurrent protection system.

[0007]

In order to achieve such an object, the first invention (the invention relating to claim 1) is
Interface means that serves as an input unit for external information is provided, and information regarding the upper overcurrent relay and information regarding the own overcurrent relay are to be input via this interface means, and based on these information, the upper overcurrent relay is input. The operation characteristic setting value that enables protection cooperation with the current relay is obtained. Further, in the second invention (the invention according to claim 2), transmission interface means is added to the overcurrent relay of the first invention, and the operation characteristic set value is transmitted to the master station via the transmission interface means. It was done. Also, in the master station, a protection cooperation curve between these overcurrent relays is created and displayed based on the operating characteristic set value transmitted from each overcurrent relay arranged in the power distribution system. Also,
The third invention (the invention according to claim 3) collectively inputs, to the master station, information about the overcurrent relays above it and information about the own overcurrent relay for each overcurrent relay arranged in the power distribution system. However, based on this information, the operating characteristic set value of each overcurrent relay that enables protection coordination with the higher-order overcurrent relay shall be obtained, and based on the obtained operating characteristic set value of each overcurrent relay, A protection coordination curve between these overcurrent relays shall be created and displayed,
The master station transmits the operation characteristic set value of each overcurrent relay determined with reference to the displayed protection cooperation curve to the corresponding overcurrent relay. The fourth invention (the invention according to claim 4) is provided with an interface unit that serves as an input unit of information from the outside, and the type of the time delay element of the upper overcurrent relay input through the interface unit, Based on the set current tap value, operation time limit dial value, CT ratio, type of load protected by its own overcurrent relay, load capacity and CT ratio, operation characteristic setting that enables protection coordination with a higher overcurrent relay As the value, the type of the time delay element, the set current tap value, and the operation time limit dial value are obtained. Also, the fifth
The invention (the invention according to claim 5) is provided with an interface unit that serves as an input unit of information from the outside, and the operating current value and the CT ratio of the instantaneous element of the higher-order overcurrent relay input through the interface unit and Based on the short-circuit capacity and CT ratio of the load protected by its own overcurrent relay, the operating current value of the instantaneous element is obtained as the operating characteristic set value that enables protection coordination with a higher-order overcurrent relay. is there.

[0008]

Therefore, according to the first aspect of the present invention, when the information regarding the upper overcurrent relay and the information regarding the own overcurrent relay are input to the overcurrent relay, the upper overcurrent relay is input based on these information. The operating characteristic set value that enables protection cooperation with the automatic setting is automatically obtained. Further, in the second aspect of the invention, the operation characteristic setting value automatically obtained by the overcurrent relay is transmitted to the master station, and the master station is an operation transmitted from each overcurrent relay arranged in the power distribution system. Based on the characteristic setting value, create and display the protection coordination curve between overcurrent relays. Further, in the third invention, when the information regarding the upper overcurrent relay and the information regarding the own overcurrent relay regarding the respective overcurrent relays arranged in the power distribution system are collectively input to the parent station, the parent station Based on this information, the operating characteristic set value of each overcurrent relay that enables protection coordination with a higher-order overcurrent relay is obtained, and a protection cooperation curve between overcurrent relays is created and displayed. When the operation characteristic set value of each overcurrent relay is confirmed with reference to the displayed protection cooperation curve, the confirmed operation characteristic set value of each overcurrent relay is transmitted from the master station to each corresponding overcurrent relay. . Further, in the fourth aspect of the invention, the type of the time delay element of the upper overcurrent relay, the set current tap value, the operation time limit dial value, the CT ratio, the type of load protected by the own overcurrent relay, and the load capacity are included in the fourth invention. By inputting the or CT ratio, the type of the time delay element, the set current tap value, and the operation time limit dial value are automatically obtained as the operation characteristic setting values that enable protection cooperation with the upper overcurrent relay. Further, in the fifth invention, when the operating current value or CT ratio of the instantaneous element of the upper overcurrent relay and the short-circuit capacity or CT ratio of the load protected by the own overcurrent relay are input to the overcurrent relay, the upper overcurrent relay is input. The operating current value of the instantaneous element is obtained as the operating characteristic setting value that enables protection coordination with the current relay.

[0009]

EXAMPLES The present invention will now be described in detail based on examples. [First Embodiment: First Invention, Fourth Invention, Fifth Invention] FIG. 1 shows an internal block diagram of an overcurrent relay according to the present invention. In the figure, 1 is an overcurrent relay, 2 is a circuit breaker controlled by this overcurrent relay 1, and 3 is a CT which is supplied to the overcurrent relay 1 after being converted into a current of 5A if the main circuit current is 100A, for example. is there. Further, in the overcurrent relay 1, 1a is an auxiliary CT for further converting a signal so that a current of 5A can be inputted to an electronic circuit, 1b is an amplifier for converting the level of the signal, 1c is a logic operation circuit for converting an analog signal into a digital signal. (Microprocessor) A / D conversion circuit for converting so as to be processed by 1d, 1f is a setting circuit for inputting information from the outside, 1g is for displaying the input information, and the calculation result in the logical operation circuit 1d is It is a display device for displaying. A man-machine interface is configured by the setting circuit 1f and the display device 1g. Reference numeral 1e is a non-volatile storage circuit, and 1h is an output device that outputs a trip command to the circuit breaker 2.

FIG. 2 is a diagram of a power distribution system using the overcurrent relay 1. In the figure, 2a is an overcurrent relay 1
Power receiving breaker controlled by (1-1), 4a is a transformer for converting extra high voltage received from a power company to high voltage for distribution, 2b is a secondary circuit breaker of transformer 4a, 2c is a primary substation Distribution breaker for supplying electric power from the secondary substation to each substation, 2d is a main circuit breaker of the secondary substation, 2e is a feeder circuit breaker for supplying electric power to each load, and 4b is a high voltage to a low voltage. A transformer for conversion, 5 is a load motor, 6 is a fuse as a load, and the circuit breaker 2b is an overcurrent relay 1 (1-
2), the circuit breaker 2c is controlled by the overcurrent relay 1 (1
-3), the circuit breaker 2d is controlled by the overcurrent relay 1
The circuit breaker 2e is controlled by the overcurrent relay 1 (1-5). In this power receiving and distribution system, the operating characteristics of the overcurrent relay 1-1 at the power receiving point are instructed by the power company because of the necessity of taking protective coordination with the power distribution system of the power company. However, the other overcurrent relays 1 need to perform protection coordination based on the operating characteristics of the overcurrent relay 1-1 at the power receiving point.

In this embodiment, protection coordination between the overcurrent relays 1 is performed as follows. For example, in the case of the overcurrent relay 1-2, the upper overcurrent relay is the power receiving breaker 2a.
It becomes the overcurrent relay 1-1 which controls. The information regarding the higher-order overcurrent relay 1-1 includes the circuit voltage of the load protected by the overcurrent relay 1-1, the type of the time delay element instructed by the power company, the set current tap value, the operation time limit dial value, and the instantaneous element. Of the operating current value and the CT ratio of the logical operation circuit 1d via the setting circuit 1f of the overcurrent relay 1-2.
To the memory circuit 1e. Next, as information about the own overcurrent relay 1-2, the overcurrent relay 1
-2 protects the circuit voltage of the load, the type of load (in this case, a circuit breaker for distribution), the load capacity, the short-circuit capacity of the load, and the CT ratio via the setting circuit 1f of the overcurrent relay 1-2. It is input to the arithmetic circuit 1d and stored in the memory circuit 1e. However, in this case, it is necessary to calculate the load capacity of the equipment in advance as the load capacity.

Based on these input information, the logical operation circuit 1d mounted on the overcurrent relay 1-2 calculates the time-delayed element characteristic 20 and the instantaneous element characteristic 21 shown in FIG. To do. Next, the instantaneous element characteristic 23 is calculated from the load short-circuit capacity, the CT ratio, and the instantaneous element characteristic 21,
The type of load, the load capacity, the CT ratio, and the time delay element characteristic 22 of the power receiving point are calculated to calculate the time delay element characteristic 22, the type of the time delay element of the overcurrent relay 1-2, the set current tap value, the operating current value of the instantaneous element, Display 1 after converting to operation time dial value
Display in g.

FIG. 5 shows a flowchart for calculating the time delay element characteristic 22 as an example. First, in step 101,
As the information about the upper overcurrent relay 1-1, the circuit voltage of the load protected by the overcurrent relay 1-1, the type of time delay element, the set current tap value, the operation time limit dial value, and the CT
The ratio is input and stored in the memory circuit 1e. Next, in step 102, the circuit voltage protected by the overcurrent relay 1-2, the type of load, the load capacity, the short-circuit capacity of the load, and the CT ratio are input as information regarding the own overcurrent relay 1-2.
It is stored in the memory circuit 1e. Then, in step 103,
Determine the type of time delay element from the type of load and select the standard time delay element characteristics. Next, in step 104, from the CT ratio of the upper overcurrent relay 1-1, the type of the time delay element, the set current tap value, and the operation time limit dial value, the overcurrent relay 1-
The time delay element characteristic 20 of 1 is calculated.

Next, at step 105, 1 is calculated from the load capacity.
Calculate the secondary current, determine the overload protection current value in the range of 1.2 to 1.5 times, convert the secondary current by CT ratio,
The set current tap value of the time delay element is calculated, and the time delay element characteristic of the minimum operation time delay dial is calculated. Next, step 10
The time-delayed element characteristic 20 calculated in step 4 is compared with the time-delayed element characteristic 20 of the upper overcurrent relay 1-1 calculated in step 4, and the value of the time-delayed element characteristic calculated in step 105 is calculated in step 104. 30 than the value of 20
Operates faster than 0 msec, and is the lower overcurrent relay 1
400 msec in consideration of cooperation with the operating characteristics of (1-3)
As described above, it is determined whether or not it is in a range in which it does not operate faster (step 106). If the determination result is YES, the type of the time delay element characteristic, the set current tap value, and the operation time limit dial value are displayed (step 110), and the confirmation input in step 111 is prompted. If the confirmation input is YES, the set value (type of time delay element, set current tap value, operation time limit dial value) is stored in the memory circuit 1e in step 112, and the process ends.

If NO in step 111, the process returns to step 101 and starts over. If the judgment in step 106 is NO, the operation time limit dial value is increased by 1 to calculate the time delay element characteristic (step 107). And
It is checked whether or not the operation time limit dial value has ended (step 108), and if it is confirmed that the value has not ended, step 10
Returning to step 6, the above-described comparison judgment is performed on the time delay element characteristic calculated in step 107. If the operation time limit dial value ends in step 108, it can be determined that the type of the time delay element characteristic is not appropriate, so a different type of time delay element characteristic is selected, the process returns to step 105, and step 106 and subsequent steps are repeated. In this way, in the overcurrent relay 1-2, the time delay element characteristic 2 in the higher-order overcurrent relay 1-1
For 0, the time delay element characteristic 22 with protection cooperation is automatically obtained.

Since the instantaneous element 23 is a protection function against a short circuit accident of the system, it does not require complicated processing such as a time delay element, and the operating current value of the instantaneous element of the upper overcurrent relay 1-1 is input. , In the memory circuit 1e. Next, the C stored in the memory circuit 1e when the time element is calculated
Calculate the primary current from the T ratio. Next, the secondary current flowing to the self is calculated from the own CT ratio stored in the storage circuit 1e when the time element is also calculated and the calculated primary current. Compare the calculated secondary current with the current tap set in the upper overcurrent relay 1-1, set the current tap one step lower, prompt confirmation input, and if the confirmation input is YES , The setting value is stored in the memory circuit 1e, and the process is ended. The above operation is performed in the order of lower overcurrent relay 1
By performing (1-3 to 1-5), the operating characteristics of all overcurrent relays 1 of the power receiving and distribution system can be performed easily and quickly with little labor.

[Second Embodiment: Second Invention] FIG. 3 is an internal configuration diagram of an overcurrent relay 1 to which a transmission interface is added and an internal configuration diagram of a transmission master station. In this case, the overcurrent relay 1 sets the set value (type of time delay element, set current tap value, operating time limit dial value, operating current of the instantaneous element) via the transmission interface configured by the receiving unit 1i and the transmitting unit 1j. (Value) is transmitted / received to / from the master station 8 having higher capability. The master station 8 creates a protection cooperation curve between these overcurrent relays based on the set value transmitted from each overcurrent relay 1 arranged in the power distribution system, and displays it on the display device 8d. This allows the legitimacy of protection cooperation to be confirmed on the screen at a glance. In the case where there are multiple levels of hierarchy, there is a possibility that automatic setting may not be possible. In such a case, the master station 8 analyzes the protection cooperation curve, artificially corrects the part that cannot be automatically set, and sends the corrected set value to the required overcurrent relay 1 via the transmitter 8i. It is also possible to return it.

In FIG. 3, 8a is a control unit, and 8b is
Is a storage device, 8c is a keyboard, 8j is a receiving unit,
The transmitter 8i and the receiver 8j constitute a transmission interface. The master station 8 is also capable of advanced calculations such as automatic calculation of load capacity. [Third Embodiment: Third Invention] In the first and second embodiments, the information about the upper overcurrent relay and the information about the own overcurrent relay are individually input to each overcurrent relay 1. You may make it input into the station 8 collectively. That is, regarding each overcurrent relay 1 arranged in the power distribution system, the information regarding the upper overcurrent relay and the information regarding the own overcurrent relay are collectively input to the master station 8 and the upper order is performed based on these information. The operating characteristic set value of each overcurrent relay 1 which enables the protective cooperation with the overcurrent relay 1 is obtained, and the protective cooperation between these overcurrent relays is based on the obtained operating characteristic set value of each overcurrent relay 1. A curve should be created and displayed, and after confirming the validity of the displayed protection cooperation curve, the determined operation characteristic set value of each overcurrent relay 1 is transmitted to each overcurrent relay 1 via the transmission interface. You may do it. According to this embodiment, since it is not necessary to input information to each overcurrent relay 1 on site, the labor can be further reduced. FIG. 4 shows an example of a delivery and distribution system diagram using the overcurrent relay 1 to which a transmission interface is added.

[0019]

As is apparent from the above description, according to the present invention, in the first invention, when the information about the upper overcurrent relay and the information about the own overcurrent relay are input to the overcurrent relay, The operating characteristic set value that enables protection coordination with a higher-level overcurrent relay will be automatically obtained based on the information in (1), and the setting of operating characteristics that enables protection coordination with a higher-level overcurrent relay will be reduced. It can be done easily and quickly with effort. Also,
In the second aspect of the invention, the operating characteristic setting value automatically obtained by the overcurrent relay is transmitted to the master station, and the master station sets the operating characteristic setting transmitted from each overcurrent relay arranged in the power distribution system. In response to the value, the protection cooperation curve between overcurrent relays is created and displayed. Therefore, in addition to the effect of the first invention, the justification of protection cooperation between overcurrent relays can be confirmed at a glance, and automatic setting is possible. It is possible to deal with the impossible part by artificially making corrections. Also, the third
In the invention, when the information regarding the upper overcurrent relay and the information regarding the own overcurrent relay regarding each overcurrent relay arranged in the power distribution system are collectively input to the master station,
Based on this information, the master station obtains the operating characteristic set value of each overcurrent relay that enables protection coordination with the upper overcurrent relay, creates and displays the protection cooperation curve between overcurrent relays, and displays this. When the operation characteristic set value of each overcurrent relay is confirmed with reference to the displayed protection cooperation curve, the confirmed operation characteristic set value of each overcurrent relay is transmitted from the master station to each corresponding overcurrent relay. Then, the first invention, the second
In addition to the same effect as the invention, it is possible to further reduce the labor by eliminating the need to input information to each overcurrent relay in the field. Further, in the fourth aspect of the invention, the type of the time delay element of the upper overcurrent relay, the set current tap value, the operation time limit dial value, the CT ratio, the type of load protected by the own overcurrent relay, and the load capacity are included in the fourth invention. Or CT ratio, the type of time delay element, the set current tap value, and the operation time limit dial value are automatically obtained as the operation characteristic setting values that enable protection coordination with the higher-level overcurrent relay. In the fifth invention, when the operating current value or CT ratio of the instantaneous element of the upper overcurrent relay and the short-circuit capacity or CT ratio of the load protected by the own overcurrent relay are input to the overcurrent relay, the upper overcurrent relay is input. The operating current value of the instantaneous element is obtained as the operating characteristic setting value that enables protection cooperation with the above, and the same effect as the first aspect of the invention is obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal block diagram of an overcurrent relay according to the present invention.

FIG. 2 is a diagram of a power distribution system using this overcurrent relay.

FIG. 3 is a diagram showing an internal configuration of an overcurrent relay to which a transmission interface is added and an internal configuration of a transmission master station.

FIG. 4 is a diagram showing an example of a power distribution system using an overcurrent relay to which a transmission interface is added.

FIG. 5 is a flowchart for explaining the calculation of the time delay element characteristic in this overcurrent relay.

FIG. 6 is a diagram showing an example of a protection cooperation table.

FIG. 7 is a diagram showing an example of operating characteristics of a time delay element of an overcurrent relay.

FIG. 8 is a diagram showing an example of setting the operation time of the anti-time limit characteristic by the operation time limit dial value.

[Explanation of symbols]

1 Overcurrent relay, 1a Auxiliary CT, 1b amplifier, 1
c A / D conversion circuit, 1d logical operation circuit (microprocessor), 1e storage circuit, 1f setting circuit, 1g
Display device, 1h output device, 1i receiving unit, 1j transmitting unit, 2 circuit breaker, 3 CT, 4 transformer, 5 motor,
6 fuses, 7 transmission lines, 8 master station, 8a control unit,
8b storage device, 8c keyboard, 8d display device,
8i transmitter, 8j receiver.

Claims (5)

[Claims] 1. An upper-order overcurrent is based on interface means which is an input section of information from the outside, and information about the upper-order overcurrent relay and information about its own overcurrent relay which are input via this interface means. An overcurrent relay, comprising: an operating characteristic set value deriving means for obtaining an operating characteristic set value that enables protection cooperation with a relay. 2. An overcurrent relay according to claim 1, wherein transmission interface means is added, and the operating characteristic set value is transmitted to the master station via the transmission interface means, while the master station is arranged in a power distribution system. An overcurrent protection system characterized in that a protection coordination curve between these overcurrent relays is created and displayed based on operation characteristic set values transmitted from each overcurrent relay. 3. With respect to each overcurrent relay arranged in the power distribution system, information regarding the upper overcurrent relay and information regarding the own overcurrent relay are collectively input, and based on these information, the upper overcurrent relay is selected. Based on the operating characteristic set value of each overcurrent relay obtained by the operating characteristic set value deriving means, the operating characteristic set value deriving means for obtaining the operating characteristic set value of each overcurrent relay enabling the protection cooperation of Display means for creating and displaying the protection cooperation curve between the current relays, and the operating characteristic set value of each overcurrent relay confirmed with reference to the protection cooperation curve displayed by this display means is transmitted to each corresponding overcurrent relay. An overcurrent protection system comprising a master station having a transmission interface means. 4. The interface means forming an input portion of information from the outside, and the type of the time-delay element of the upper overcurrent relay input via the interface means, the set current tap value, the operation time-dial value and the CT ratio. Based on the type of load protected by its own overcurrent relay, load capacity and CT ratio, the type of time delay element, set current tap value and An overcurrent relay, comprising: an operation characteristic set value deriving means for obtaining an operation time limit dial value. 5. An interface means forming an input portion of information from the outside, and an operating current value and a CT ratio of an instantaneous element of a higher-order overcurrent relay input via the interface means and a self-overcurrent relay are protected. And an operating characteristic set value deriving means for obtaining an operating current value of an instantaneous element as an operating characteristic set value that enables protection coordination with a higher-order overcurrent relay, based on the short-circuit capacity and CT ratio of the load. Characteristic overcurrent relay.