JP2018033282A - Bus bar monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bus bar monitoring device capable of contributing to improvement of reliability of electric power substation operation by monitoring a load state of a bus bar based on a feeder current measured by an instrument current transformer.SOLUTION: In an instrument current transformer 4 attached to a feeder 2, magnitude and a direction of a current flowing through the feeder 2 are measured. A current calculation part 12 calculates a bus bar current 9 being a current value of a predetermined section of a bus bar 3 based on a measured value of the instrument current transformer 4. An abnormality detection part 13 and an output part 14 are sequentially connected to the current calculation part 12. The abnormality detection part 13 detects the bus bar current 9 being deviated from a preset reference value. When the abnormality detection part 13 detects the bus bar current 9 being deviated from the reference value, the output part 14 outputs an alarm.SELECTED DRAWING: Figure 6

Description

  Embodiments described herein relate generally to an apparatus for monitoring a bus provided in a switching device of a substation.

  A feeder is incorporated in the switchgear of the substation used in the transmission and substation system. The feeder includes a power receiving feeder and a power transmission feeder. The power receiving feeder concentrates the current from the opposite substation, power plant or transformer on the bus, and the power feeder distributes the current flowing through the bus to the transformer or each system. The current flowing through the feeder will be referred to as feeder current.

  An instrument current transformer for measuring feeder current is attached to the outer periphery of the conductor of the feeder. The switchgear of the substation includes a control panel, a protection panel, a protection relay, and a circuit breaker, together with a current transformer for the instrument, and plays a role of removing an accident current. In other words, the feeder current flowing through the feeder is measured by the instrument current transformer, and the measurement result is taken into the control panel and the protection panel via a conductor or the like. When an accident occurs in the system, an abnormal current is detected in the control panel and the protection panel. Thereby, in the switchgear of a substation, a protection relay act | operates and a circuit breaker operates and it can remove an accident current.

JP-A-10-260294

  As described above, in a substation switchgear, an instrumental current transformer detects an abnormal current due to a system fault by measuring a feeder current. The current flowing in the bus section changes according to the feeder current in each feeder. For this reason, the current burden of the bus section is partially increased, and a current exceeding the rating may flow through the bus. As a result, the amount of heat generated at the busbar may increase, leading to an increase in busbar temperature.

  In the prior art, the instrument current transformer is only attached to the feeder, and no device for measuring the current flowing through the bus is attached to the bus. Therefore, the load state of the bus due to the feeder current has not been grasped. In recent years, it has been required to improve the reliability of substation operation, and it has been required to monitor the load state of the bus.

  This embodiment is made to solve the above-mentioned problem, and by monitoring the load state of the bus based on the feeder current measured by the current transformer for the instrument, the reliability of the operation of the substation is improved. It aims at providing the bus-line monitoring apparatus which can contribute.

In order to achieve the above object, an embodiment of the present invention is a bus monitoring device that is provided in a switching device of a substation having a feeder and a bus connected to the feeder, and monitors the bus. (1) and (2).
(1) A current transformer for an instrument which is attached to the feeder and measures the magnitude and direction of the feeder current flowing through the feeder.
(2) A current calculation unit that calculates a current value in a predetermined section of the bus bar based on a measurement value of the instrument current transformer.

Single wire connection diagram of switchgear of single bus system substation. Single line connection diagram of the switchgear of a double bus system substation. Single line connection diagram of switchgear of 1/1/2 line type substation. A single-line diagram of a substation switchgear that considers the double-bus system as a single-bus system. A single-line diagram of a substation switchgear that considers the double-bus system as a single-bus system. The single line connection diagram and block diagram of 1st Embodiment. The single wire connection diagram and block diagram of 4th Embodiment. The figure which shows the example of a display of 5th Embodiment. The single wire connection diagram and block diagram (overcurrent state) of 6th Embodiment. The single wire connection diagram and block diagram (bus switching state) of 6th Embodiment. The single wire connection diagram and block diagram (both bus-bridge state) of 7th Embodiment. The single wire connection diagram and block diagram (overcurrent state) of 7th Embodiment. The single line connection diagram and block diagram (bus line switching state) of 7th Embodiment.

  Embodiments according to the present invention will be described. Each of the following embodiments is a device for monitoring a bus bar incorporated in a switching device of a substation. In addition, since the basic composition of each embodiment is the same, in 2nd and subsequent embodiment, the same code | symbol is attached | subjected about the component similar to 1st Embodiment, and description is abbreviate | omitted.

(Outline of switchgear of substation)
The outline of the switchgear of the substation will be briefly described with reference to FIGS. As a bus system in a substation switchgear, the single bus system 1 shown in FIG. 1, the multiple bus system 6 shown in FIG. 2, the 11/2 line system 7 shown in FIG. 3, and the like are known. . 1 to 3 are typical single-line diagrams in these systems. 4 and 5 are single line connection diagrams of the switchgear of the substation when the double bus system is regarded as a single bus system.

  As shown in FIG. 1, the single-bus system 1 substation switchgear includes a plurality of feeders 2 including a power receiving feeder 2 a and a power transmitting feeder 2 b, a bus 3 that connects the power receiving feeder 2 a and the power transmitting feeder 2 b, An instrument current transformer 4 attached to each feeder 2 is provided. In such a switchgear, the current from the opposite substation, power plant or transformer is concentrated on the bus 3 via the power receiving feeder 2a, and from the bus 3 to the transformer or each system via the power feeder 2b. And distribute power.

  Two busbars 3a and 3b are provided in the switching device of the substation of the double bus system 6 shown in FIG. 2 and the switching device of the substation of the 1 · 1/2 line system 7 shown in FIG. In the double bus system 6 and the 11/2 line system 7, either one of the two buses 3a and 3b is selected according to the operation status of the substation, and the current is concentrated on the bus. .

  As shown in FIGS. 4 and 5, if attention is paid to the feeder 2 connected to each of the buses 3a and 3b, the multi-bus system 6 can be regarded as the same as the single-bus system 1. The 1½ line system 7 is the same as the double bus system 6. Therefore, in the following embodiments, the description will be made on the premise that the single bus system 1 is used, but the embodiments can be applied to the multiple bus system 6 or the 1 · 1/2 line system 7.

(1) First embodiment (configuration)
The configuration of the bus monitoring device according to the first embodiment will be described with reference to FIG. FIG. 6 is a diagram in which a block diagram showing components is added to the simplified single-line diagram of FIG. 1. As shown in FIG. 6, in the first embodiment, the feeder 2 includes “feeder 1” to “feeder n + 1”. The section of bus 3 sandwiched between “feeder 1” and “feeder 2” is “bus section 1”, and the section of bus 3 sandwiched between “feeder 2” and “feeder 3” is “bus section 2”. The section of bus 3 sandwiched between “feeder n−1” and “feeder n” is the section of bus 3 sandwiched between “bus section n−1” and “feeder n” and “feeder n + 1”. Is “bus section n”.

  An instrument current transformer 4 is attached to each feeder 2. The instrument current transformer 4 measures the magnitude and direction of the feeder current 8 flowing through each feeder 2. Regarding the direction of the feeder current 8, the direction flowing into the bus 3 is positive, that is, the direction of the arrow drawn beside each feeder 2 in FIG. 6 is positive.

  The measurement value of each instrument current transformer 4 is sent to the control panel and the protection panel via a conductor or the like. The control panel is provided with a current calculation unit 12, an abnormality detection unit 13, and an output unit 14. The current calculation unit 12 receives the measurement value from each instrument current transformer 4, and based on the measurement value of the instrument current transformer 4, the current value of the bus 3 (specifically, the current value for each bus section) , Hereinafter referred to as bus current 9). The current calculation unit 12 calculates the bus current 9 based on the current direction defined above. However, even if the current direction is set to be opposite to that of the present embodiment, only the sign of the bus current 9 is changed. There is no change in the essential content because it can respond.

  An abnormality detection unit 13 and an output unit 14 are sequentially connected to the current calculation unit 12. The abnormality detection unit 13 detects that the bus current 9 has deviated from a preset reference value and sends a detection signal to the output unit 14. When receiving the detection signal from the abnormality detection unit 13, the output unit 14 outputs an alarm indicating that the bus current 9 has deviated from the reference value. The alarm output from the output unit 14 may be a sound or may be displayed as an image.

ここでＩ_Ｆｋは、ｋ(=1, 2, 3,…n+1)番目のフィーダ電流８の瞬時値を示している。Ａ_Ｆｋはｋ番目のフィーダ２におけるフィーダ電流８の実効値を示し、ｆは系統における周波数を示す。 A general current in AC power transmission can be expressed by the following equation (1).
(Equation 1)

Here, _IFk represents the instantaneous value of the k (= 1, 2, 3,... N + 1) th feeder current 8. A _Fk indicates an effective value of the feeder current 8 in the k-th feeder 2, and f indicates a frequency in the system.

母線電流９は、図６で左から右への方向を正、すなわち母線３の上方に描かれた矢印の方向を正とする。 Than this, the bus interval k the bus current 9 in (= 1, 2, 3, ... n) if I _Bk, I _Bk can be expressed as the following equation (2).
(Equation 2)

In the bus current 9, the direction from left to right in FIG. 6 is positive, that is, the direction of the arrow drawn above the bus 3 is positive.

In the current calculation unit 12, the bus current 9 is obtained using the effective value A _Fk in the feeder current 8 by changing the above formula (2) to the following formula (3). The effective value A _Fk of the feeder current 8 is a positive value if the feeder current 8 flows in the direction in which the feeder current 8 flows into the bus 3 (power reception), and if the feeder current 8 flows in the direction in which the feeder current 8 flows out of the bus 3 (power transmission). Negative value.
(Equation 3)

(Effect and action)
In the first embodiment described above, the current calculation unit 12 uses the effective value of the feeder current 8 based on the measurement value of the current transformer 4 for measuring the bus current 9 flowing in the bus 3 (specifically, Current value for each bus section) can be calculated. If the bus current 9 deviates from a preset reference value, the abnormality detection unit 13 detects this and the output unit 14 outputs an alarm.

  According to the first embodiment as described above, the load state in each section of the bus 3 can be monitored, and an optimal substation operation is realized, such as reducing the current flowing through the bus 3 based on the monitoring result. It becomes possible. Therefore, it is possible to avoid an increase in the temperature of the bus 3 due to an increase in load. Further, by applying the calculation method by the current calculation unit 12 at the design stage, it is also possible to perform the layout design of the feeder 2 in which the power flow distribution of the bus 3 is optimal. Thereby, it can contribute to the reliability improvement of substation operation.

(2) Second embodiment (configuration)
In the second embodiment, the instrument current transformer 4 measures the voltage reference phase angle in addition to the magnitude and direction of the feeder current 8. The current calculation unit 12 takes in the voltage reference phase angle measured by the instrument current transformer 4 and calculates a bus current 9 (specifically, a current value for each bus section).

  In an actual power system, since the impedance of each system differs depending on the length and type of transmission lines, the number of customers, and the like, a phase difference occurs in the feeder current 8 flowing through each feeder 2. Therefore, by taking in the voltage reference phase angle of the feeder current 8 in the current calculation unit 12, the bus current 9 can be calculated with high accuracy.

このフィーダ電流８の瞬時値であるＩ_Ｆｋを上記の式（２）に代入することで、電流算出部１２は、電圧基準位相角を考慮した母線電流９を算出することができる。 If the voltage reference phase angle of the feeder current 8 in the feeder 2 and theta _Fk, I _Fk is the instantaneous value of the feeder current 8 can be expressed as the following equation (4).
(Equation 4)

By substituting _IFk which is an instantaneous value of the feeder current 8 into the above equation (2), the current calculation unit 12 can calculate the bus current 9 in consideration of the voltage reference phase angle.

(Effect and action)
The second embodiment takes into account the voltage reference phase angle of the feeder current 8 in addition to A _Fk which is the effective value of the feeder current 8, thereby enabling a more accurate bus current 9 (specifically, the bus section). Current value) can be calculated. Therefore, in the second embodiment, it becomes possible to monitor the load state in each section of the bus 3 with high accuracy, and the reliability of the substation operation can be further improved by selecting the optimum substation operation. .

(3) Third embodiment (configuration)
In the third embodiment, the instrument current transformer 4 measures an instantaneous value of the feeder current 8, and the current calculation unit 12 uses the instantaneous value of the feeder current 8 to determine the bus current 9 (specifically, the bus section). The instantaneous value of each current value is obtained.

When the voltage reference phase angle of the feeder current 8 in the “feeder 1” is 0 and the phase difference of the feeder current 8 with respect to the “feeder 1” of “feeder k” is θ _Fk , the above formula ( 1) changes as the following formula (5).
(Equation 5)

At this time, by using the instantaneous value of the bus current 9, the above formula (2) for _obtaining I _Bk of the bus current 9 in each bus section k (= 1, 2, 3,... N) is expressed by the following formula ( It changes as in 6).
(Equation 6)

(Effect and action)
In the third embodiment, the instrument current transformer 4 measures an instantaneous value of the feeder current 8, and the current calculation unit 12 uses the instantaneous value of the feeder current 8 to determine the bus current 9 (specifically, the bus current). Since the instantaneous value of the current value for each section is obtained, it is not necessary to consider the magnitude of the feeder current 8 and the voltage reference phase angle individually as in the second embodiment. Therefore, it is possible to quickly monitor the load state in each section of the bus 3. Thereby, the substation operation according to the load state in each section of the bus 3 can be selected at an appropriate timing, and the reliability of the substation operation can be further improved.

(4) Fourth embodiment (configuration)
The configuration of the fourth embodiment will be described with reference to FIG. As shown in FIG. 7, in the fourth embodiment, a heat generation amount calculation unit 11 is connected to the current calculation unit 12, and a display unit 10 is connected to the heat generation amount calculation unit 11. The calorific value calculation unit 11 takes in the bus current 9 calculated by the current calculation unit 12 (specifically, the current value for each bus section) and the resistance value of the bus 3, and based on these, the bus 3 The calorific value per unit time in each section is calculated. A display unit 10 is connected to the calorific value calculation unit 11. The display unit 10 displays the heat generation amount per unit time of the bus section calculated by the heat generation amount calculation unit 11.

  As a method of knowing the resistance value of the bus bar 3, there are a method of directly measuring the resistance value of the circuit, a method of calculating the resistance value of the circuit from the material, shape and contact structure of the conductor. The calorific value calculation unit 11 takes in the resistance value of the bus 3 obtained by these methods, and multiplies the resistance value by the square of the bus current 9, so that the per unit time in the respective sections of the bus 3 is calculated. Lead the heat generation.

Specifically, the heat generation amount calculation unit 11 sets the resistance value of each bus section as R _Bk , and calculates the heat generation amount W _Bk per unit time in each section of each bus 3 based on the following equation (7). calculate.
(Equation 7)

(Effect and action)
In the fourth embodiment, the heat generation amount calculation unit 11 calculates the heat generation amount W _Bk per unit time in each section of the bus 3, and the display unit 10 displays the heat generation amount W _Bk per unit time of the bus 3. To do. Therefore, the user can indirectly grasp the temperature rise of the bus 3. According to the fourth embodiment, even when the load on the bus 3 increases and the temperature of the bus 3 rises, the substation operation can be performed to suppress the temperature rise of the bus 3, The reliability of operation is further improved.

(5) Fifth embodiment (configuration)
The configuration of the fifth embodiment will be described with reference to FIG. As shown in FIG. 8, in the fifth embodiment, the operation of the bus 3 in each section is based on the bus current 9 calculated by the current calculation unit 12 (specifically, the current value for each bus section). A display unit 10 for displaying the situation is provided.

  The display unit 10 has a display screen 15, which displays a single line connection diagram on the substation automation system on the display screen 15 and displays a display window 16 in the vicinity of each bus section on the single line connection diagram. . The display unit 10 receives information related to the bus current 9 from the current calculation unit 12 and displays the magnitude of the bus current 9 in the display window 16.

  The display part 10 displays the driving | running state of the bus-bar 3 in a several different aspect based on the preset reference value. As a display mode by the display unit 10, for example, the display window 16 itself is displayed in different colors depending on whether the magnitude of the bus current 9 is greater than or equal to a set reference value or less than the set reference value.

  In the example shown in FIG. 8, 3000A is set as the reference value of the bus current 9, and 2500A of the Kobus section k-1 which is 3000A or less, and 1200A of the Otobus section k-1 and the Otobus section k are displayed. The portion to be displayed is displayed in green (shown in white in FIG. 8). In addition, the portion displaying 3500A of the upper bus k exceeding the reference value is displayed in red (indicated by crossed diagonal lines in FIG. 8).

  Further, the display unit 10 indicates the direction of the bus current 9 by displaying a positive / negative sign at the beginning of the current value of the bus current 9. However, the display of the positive sign is omitted as usual. For example, in the display window 16 shown in FIG. 8, 2500A is displayed in the bus line section k-1, 3500A is displayed in the bus line section k, and -1200A is displayed in the Otobus line section k-1 and the Otobus line section k. The display unit 10 may display an arrow near the display window 16 on the display screen 15 as a display shown in the direction of the bus current 9.

(Action and effect)
In the fifth embodiment, the display unit 10 can display the value of the bus current 9 in the display window 16 in different colors. Therefore, the user using the fifth embodiment can visually recognize the driving state of the bus 3 and can easily and reliably recognize the load state of the bus 3. Thereby, it can contribute to the reliability improvement of substation operation.

(6) Sixth embodiment (configuration)
The configuration of the sixth embodiment will be described with reference to FIGS. 9 and 10. The sixth embodiment is a bus monitoring device provided in a switching device of a substation of a double bus system 6. As shown in FIGS. 9 and 10, in the sixth embodiment, an overcurrent detection unit 17 and a feeder control unit 18 are sequentially connected to the current calculation unit 12.

  The overcurrent detection unit 17 detects an overcurrent state in each section of the bus 3 based on the bus current 9 calculated by the current calculation unit 12 (specifically, the current value for each bus section). For example, in FIG. 9, the overcurrent detection unit 17 detects an overcurrent state of the bus 3a, and assumes that the current in the busbar section k is higher than a specified value and is in an overcurrent state. It is assumed that the feeder 2 having a great influence is the feeder k.

  At this time, the magnitude of the bus current 9 displayed on the display window 16 is 2500 A in the Kobus section k-1, 3500 A in the Kobus section k, Otsubus section k-1, and Otsu, as shown in FIG. It is -1200A in the bus section k. Further, in each display window 16, only the 3500A portion of the bus line section k is displayed in red (indicated by the crossed diagonal lines in FIG. 9), and the numerical values of the other portions are displayed in green (in FIG. 9, the outline is white). ).

When the overcurrent detection unit 17 detects an overcurrent state of one bus 3a of the multiple buses, the feeder control unit 18 switches the switch 5 with respect to the connection destination of the feeder k that greatly affects the overcurrent state of the bus 3a. Switch to the other bus 3b (the portion surrounded by the dotted line in FIGS. 9 and 10, black circles indicate “closed”, white circles indicate “open”, and so on). As a result, by the amount of feeder current 8I _Fk in the feeder k, it is possible to reduce the bus current 9 instep bus segment k.

  Therefore, as shown in FIG. 10, in the display window 16 in the bus section k, it is displayed that the size of the bus current 9 has changed from 3500A shown in FIG. 9 to 2500A, and changes from red to green. (Indicated in white in FIG. 10). In the second bus section k-1 and the second bus section k, the bus current 9 in the second bus section k-1 changes from -1200A to -2200A when the state shifts from the state of FIG. 9 to FIG. The bus current 9 in the second bus section k remains -1200A.

(Action and effect)
In the above sixth embodiment, when the overcurrent detection unit 17 detects an overcurrent state of one of the multiple buses, the feeder control unit 18 switches the connection destination of the feeder 2 to the other bus 3b. As a result, the bus current 9 can be reduced. Therefore, it becomes possible to eliminate the overcurrent in a specific bus section, the load state of the bus 3 is reduced, and the reliability of substation operation is improved.

(7) Seventh embodiment (configuration)
The configuration of the seventh embodiment will be described with reference to FIGS. 9 and 11 to 13. The seventh embodiment, like the sixth embodiment, is a bus monitoring device provided in a switching device of a substation with a multiple bus system 7, and includes an overcurrent detection unit 17 and a feeder control unit 18. Yes. In the feeder control unit 18 according to the seventh embodiment, when the overcurrent detection unit 17 detects an overcurrent state in each section of one bus 3 of the multiple buses, the switch 5 is operated, and the feeder 2 is Both buses 3a and 3b are connected to be in a state where both buses are bridged.

  The overcurrent detection unit 17 detects an overcurrent state of the bus 3a, and the current in the bus section k is higher than a specified value and is in an overcurrent state. At this time, it is assumed that the feeder 2 having a large influence on the overcurrent in the bus section k is the feeder k (see FIG. 9). In such a case, the feeder control unit 18 of the seventh embodiment operates the switch 5 to connect the feeder 2 to both the buses 3a and 3b so that both buses are bridged. For example, as shown in FIG. 11, when the two buses are bridged (the portion surrounded by the dotted line in FIG. 11), the display window 16 of the instep bus k changes from 3500A shown in FIG. 9 to 3000A and is displayed in green. (Indicated in white in FIG. 11). Therefore, all the display windows 16 are displayed in green.

  The overcurrent detection unit 17 may continue to detect overcurrent in one bus 3a even after the both bus bridges are set. For example, as shown in FIG. 12, 3100A is displayed in red in the display window 16 of the upper bus line k (indicated by crossed diagonal lines in FIG. 12). In such a case, the feeder control unit 18 of the seventh embodiment operates the switch 5 and sets the connection destination of the feeder 2, for example, the feeder k-1, different from the feeder k in the both bus bridge state, The switch 5 is operated to switch from the bus 3a to one bus 3b (the portion surrounded by the dotted line in FIGS. 12 and 13). As a result, as shown in FIG. 13, the magnitude of the bus current 9 is changed from 3100A to 2600A shown in FIG. ). The magnitude of the bus current 9 is 2500A to 2000A in the display window 16 in the bus section k-1.

(Action and effect)
In the seventh embodiment, when the overcurrent detection unit 17 detects an overcurrent state of one bus 3a or 3b of the multiple buses, the feeder control unit 18 connects the feeder 2 to both the buses 3a and 3b. To make both bus bridges. Thereby, feeder current _IFk is _shunted to both buses 3a and 3b, and bus current 9 of bus 3a or 3b in an overcurrent state can be reduced. Therefore, an overcurrent in a specific bus section can be eliminated, and the reliability of substation operation can be improved.

Further, in the seventh embodiment, when the feeder 2 is connected to both of the buses 3a and 3b and the both-bus bridge state is established, the overcurrent detection unit 17 continues to detect the overcurrent state of the bus 3a or 3b. In this case, the feeder control unit 18 switches the connection destination of the feeder 2 different from the feeder 2 in the state where both the buses are bridged to the other bus 3a or 3b. Thereby, the bus current 9 can be reduced by the amount of _IFk which is the feeder current 8, the overcurrent in a specific bus section is eliminated, the load state of the bus 3 is reduced, and the reliability of substation operation is reduced. Will improve.

(8) Other Embodiments Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  For example, in the display unit 10 of the fifth embodiment, information on the heat generation amount per unit time of the bus section is received from the heat generation amount calculation unit 11 and the heat generation amount of the bus section per unit time is also displayed in the display window 16. You may make it do. At this time, if the calorific value is equal to or less than a specified value, the display color of the display window 16 may be green to indicate that the bus 3 is being operated at a current lower than the rated value. In addition, when the calorific value is equal to or greater than a specified value, the display color of the display window 16 may be red so that the user can easily recognize an abnormal situation.

DESCRIPTION OF SYMBOLS 1 ... Single bus system 2 ... Feeder 2a ... Receiving feeder 2b ... Power transmission feeder 3 ... Bus 4 ... Current transformer 6 ... Double bus system 7 ... 11/2 line system 8 ... Feeder current 9 ... Bus current 10 ... Display unit 11 ... Heat generation amount calculation unit 12 ... Current calculation unit 13 ... Abnormality detection unit 14 ... Output unit 15 ... Display screen 16 ... Display window 17 ... Overcurrent detection unit 18 ... Feeder control unit

Claims (10)

A bus monitoring device that is provided in a switching device of a substation having a feeder and a bus connected to the feeder, and monitors the bus,
An instrument current transformer that is attached to the feeder and measures the magnitude and direction of a feeder current flowing through the feeder;
A current calculation unit that calculates a current value of a predetermined section of the bus based on a measurement value of the current transformer for the instrument;
Bus monitoring device with   The bus monitoring device according to claim 1, further comprising an abnormality detection unit that detects that the current value of the bus deviates from a preset reference value.   The bus monitoring device according to claim 2, further comprising an output unit that outputs an alarm when the abnormality detection unit detects a deviation from a reference value in the current value of the bus. The instrument current transformer measures a voltage reference phase angle of the feeder current,
The bus monitoring device according to claim 1, wherein the current calculation unit calculates a current value of a predetermined section of the bus by taking in the voltage reference phase angle. The current transformer for an instrument measures an instantaneous value of the feeder current,
The bus monitoring device according to any one of claims 1 to 4, wherein the current calculation unit calculates a current value of a predetermined section of the bus using an instantaneous value of the feeder current.   A calorific value calculation unit for calculating a calorific value per unit time of the bus section based on the current value of the predetermined section of the bus calculated by the current calculation section and the main circuit resistance of the bus section; The bus-bar monitoring apparatus of any one of Claims 1-5 provided.   The bus monitoring device according to any one of claims 1 to 6, further comprising a display unit that displays an operation status of the bus section based on a current value of a predetermined section of the bus calculated by the current calculation unit. A bus monitoring device provided in a switching device of a double bus system substation,
An overcurrent detection unit capable of detecting an overcurrent state of the bus section based on a current value of a predetermined section of the bus calculated by the current calculation unit;
When the overcurrent detection unit detects an overcurrent state of one of the buses of a multiple bus, a feeder control unit that switches the connection destination of the feeder to the other bus;
The bus monitoring device according to any one of claims 1 to 7, further comprising: A bus monitoring device provided in a switching device of a double bus system substation,
An overcurrent detection unit capable of detecting an overcurrent state of the bus section based on a current value of a predetermined section of the bus calculated by the current calculation unit;
When the overcurrent detection unit detects an overcurrent state of one of the buses of a multiple bus, a feeder control unit that connects one or more of the feeders to both of the buses and sets both buses in a bridge state;
The bus monitoring device according to any one of claims 1 to 7, further comprising:   When the overcurrent detection unit continues to detect an overcurrent in one of the buses, the feeder control unit sets the connection destination of one or more feeders different from the feeder in a state where both buses are bridged to the other bus. The bus monitoring device according to claim 9, wherein the bus monitoring device is switched to.

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