JP7347190B2 - Switchgear replacement method - Google Patents

Description

The present invention relates to a switchgear replacement method for replacing switchgear used as power distribution equipment.

Switchgear is a switching device that opens, closes, and controls electric power, and includes circuit breakers, transformers, busbars, etc., housed in a metal cabinet. Specifically, the secondary distribution box connected to the secondary side of the distribution transformer, the station GPT box that supplies the power used within the station and the voltage used for each meter such as relays, the bus bar and other transformers. It is equipped with a bus box that connects the secondary board to the bus line, and multiple distribution boxes that distribute power to areas of demand via distribution lines (lines).

When such switchgear deteriorates over time, it is necessary to replace it with a new switchgear. When replacing switchgear, conventionally, the new switchgear is installed in a different location from the existing location (current location) in order to avoid long bank power outages and increase the reliability of power supply during the construction period. method was used. However, it is necessary to install a foundation to install new switchgear, which not only increases construction costs, but also requires installation and replacement if there is no installation space or if it interferes with the foundation of other equipment. becomes difficult.

For this reason, a method for replacing an opening/closing unit group is known that allows the replacement work of the opening/closing unit group to be performed smoothly in a small work space (for example, see Patent Document 1). This construction method connects the mobile switchgear to the transformer and to the nearby distribution line startup point, replaces the existing distribution boxes one by one with new distribution boxes, and then Electrically connects to the busbar of mobile switchgear. Additionally, the busbar of the next distribution box to be replaced is disconnected, and the power cables connected to this distribution box are transferred to the new distribution box. This type of work is carried out until all unreplaced distribution boxes are used up, and the most recently replaced new distribution line box is connected to the nearest distribution line starting point.

JP2019-122145A

By the way, the switching unit group replacement method described in Patent Document 1 requires the installation of mobile switchgear, and cannot be applied when there is no installation space or when it interferes with the foundation of other equipment. Can not. On the other hand, existing switchgear foundations may have extra space, and if this extra space can be used effectively to replace the switchgear, it is possible to replace the switchgear in its current location without installing a new foundation. Replacement is possible.

Therefore, an object of the present invention is to provide a switchgear replacement method that enables switchgear replacement without installing a new foundation.

In order to solve the above problem, the invention of claim 1 provides that an existing switchgear including an essential box including a secondary distribution box and an accessory box including a distribution box is installed on a foundation, and the existing switchgear is installed on a foundation. The switchgear replacement method involves replacing the switchgear with a new switchgear, wherein at least an essential box of the new switchgear is installed in the surplus space of the foundation, and a transformer is installed in parallel with the existing switchgear. an accessory box replacement step of removing the existing switchgear accessory box from the foundation, installing the new switchgear accessory box on the foundation, and connecting it to the transformer; , an essential box removing step of removing the essential box of the existing switchgear from the foundation.

The invention of claim 2 is the switchgear replacement method according to claim 1, in which, in the accessory box replacing step, the number of accessory boxes to be removed from the foundation in one power outage and the accessory boxes to be installed on the foundation are determined. The number of times is set so that the power outage can be performed within the allowable time.

The invention of claim 3 is the switchgear replacement method according to claim 1 or 2, wherein in the essential box installation step and the accessory box replacement step, a distribution box to which a distribution line of high importance is connected is provided. It is characterized by being replaced with priority.

The invention of claim 4 is the switchgear replacement method according to claims 1 to 3, in which, in the essential box installation step, a distribution line box of the newly installed switchgear is installed in the surplus space and the distribution line box of the newly installed switchgear is connected to the transformer. Connect.

According to the invention of claim 1, a secondary box for changing the distribution of a new switchgear is installed in the surplus space of the foundation, and an accessory box such as a distribution box is replaced on the same foundation to change the distribution of the existing switchgear. Since essential boxes such as secondary boxes are removed, switchgear can be replaced without installing a new foundation. Therefore, construction costs associated with installing a new foundation can be reduced, and even if there is no installation space or the foundations of other equipment interfere, it is possible to properly replace the switchgear.

According to the invention of claim 2, since as many accessory boxes as can be replaced within the permissible power outage time for one power outage work are sequentially replaced, it is possible to reduce the effect of power outage due to replacement of accessory boxes. .

According to the invention of claim 3, since the distribution box to which the distribution line of high importance is connected is replaced preferentially, it is possible to reduce the influence of a power outage accompanying the replacement of the distribution box.

According to the invention of claim 4, in the essential box installation step, not only the essential boxes but also the distribution line box are installed in the surplus space so that the distribution line can be brought into operation more quickly, thereby making it possible to reduce the effects of power outages. .

FIG. 2 is a conceptual diagram showing an installed state of an existing switchgear that is to be replaced by a switchgear replacement method according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing a state in which the secondary duct of the power distribution transformer is improved from the state shown in FIG. 1 . FIG. 2 is a conceptual diagram showing a state in which a secondary box for changing the arrangement of a newly installed switchgear is installed in the switchgear replacement method according to the embodiment of the present invention. 4 is a circuit diagram showing the state of FIG. 3. FIG. 5 is a circuit diagram showing a state in which the power distribution lines of the first power distribution box are switched from the state in FIG. 4. FIG. 6 is a circuit diagram showing a state in which a newly installed switchgear is connected to a transformer from the state shown in FIG. 5. FIG. 7 is a circuit diagram showing a state in which the distribution line of the first distribution line box of the newly installed switchgear is put into operation from the state shown in FIG. 6. FIG. FIG. 8 is a conceptual diagram showing a state in which the existing switchgear motherboard box is removed from the state shown in FIG. 7 and two new distribution line boxes are installed. 9 is a circuit diagram showing the state of FIG. 8. FIG. FIG. 10 is a conceptual diagram showing a state in which the remaining boxes of the existing switchgear are removed from the state shown in FIG. 9 and a newly installed motherboard/SC box is installed. 11 is a circuit diagram showing the state of FIG. 10. FIG. 12 is a circuit diagram showing a state in which replacement has been completed from the state in FIG. 11. FIG. It is a conceptual diagram which shows the other installation state of the existing switchgear which is the replacement target of the switchgear replacement method based on embodiment of this invention.

The present invention will be described below based on the illustrated embodiments.

1 to 13 show an embodiment of the present invention, and FIG. 1 is a conceptual diagram showing an installed state of an existing switchgear 100A, which is a target for replacement in the switchgear replacement method according to this embodiment. be. The existing switchgear 100A is equipped with a secondary distribution box 102A and an in-house GPT box 103A as essential boxes, and a main box 101A and three distribution boxes 104A to 106A as accessory boxes, and these boxes (cabinets) 101A 106A is installed on a rectangular foundation 110.

That is, in order from one end in the longitudinal direction of the foundation 110, distribution boxes 106A, 105A, 104A, an in-house GPT box 103A, a secondary distribution box 102A, and a motherboard box 101A are installed. Additionally, an empty surplus space 111 is provided between the motherboard box 101A and the other end of the foundation 110. In this embodiment, this surplus space 111 is large enough to accommodate three boxes 2 to 4, as will be described later.

Here, the arrangement order of the boxes 101A to 106A and the size of the surplus space 111 are not limited to these. That is, the order in which the boxes 101A to 106A are arranged is such that any one of the boxes 101A to 106A is removed from the foundation 110, and any one of the boxes 1 to 6 of the newly installed switchgear 10 is placed on the foundation in the removed space. Any order is sufficient as long as the steps of installing the devices at 110 can be performed sequentially. For example, the order as shown in FIG. 13 may be used. Further, the size of the surplus space 111 may be large enough to accommodate the required boxes, that is, the secondary distribution box 102A and the in-house GPT box 103A, and may be larger or smaller than the surplus space 111 of this embodiment. good.

Further, in this embodiment, as shown in FIG. 2, the first bank A and the second bank B are connected to the bus bar 120, and the first bank A side ) 121A is connected to the switchgear 100A, and a switchgear 100B having the same configuration as the switchgear 100A is connected to the second transformer 121B on the second bank B side. The main box 101A of the switchgear 100A and the main box 101B of the switchgear 100B are connected via the interconnection line 122.

A switchgear replacement method for replacing such an existing switchgear 100A with a newly installed switchgear 10 will be described below. Here, assume that transformer power outage and bank power outage are possible only on Saturdays, Sundays, and holidays. In other words, the allowable power outage time for one power outage operation is two or three consecutive days. In addition, when restoring a bank power outage, it is necessary to use bank A and bank B bus circuit breakers in parallel, and it is not possible to use bank A and bank B in parallel using power distribution lines. In addition, the newly installed switchgear 10 has the same configuration as the existing switchgear 100A, with 1 main unit/SC box (attached box), 2 secondary distribution boxes (required box), and 3 in-house GPT boxes (required box). and three distribution boxes (auxiliary boxes) 4 to 6. Here, SC indicates a power factor correction capacitor device (stacon).

In the switchgear replacement method, first, as a duct modification step, as shown in FIG. 2, the duct 123 on the secondary side of the first transformer 121A is modified and a branch duct 124 is added to make it a bifurcated duct. Here, the secondary side cable of the first transformer 121A is housed in the duct 123, and the cable from the newly installed switchgear 10 is housed in the branch duct 124. By providing the branch duct 124 in this manner, a cable (distribution secondary cable) from the newly installed switchgear 10 can be connected to the first transformer 121A through the branch duct 124, as will be described later. In this duct remodeling step, the area including the primary circuit breaker 131, secondary circuit breaker 132, and busbar communication circuit breaker 133 of the first transformer 121A becomes the power outage range BA.

Next, as shown in FIG. 3, as an essential box installation step, at least the essential box of the newly installed switchgear 10 is installed in the surplus space 111 of the foundation 110, and the first transformer 121A is installed in parallel with the existing switchgear 100A. Connect to. In this embodiment, first, the size of the surplus space 111, the allowable power outage time, and the required work time are taken into account to determine the size of the newly installed switchgear 10, the distribution secondary box 2, the in-house GPT box 3, and the first distribution box. 4 is installed in the surplus space 111, and a distribution secondary cable is laid. At this time, as shown in FIG. 4, the area from the branch duct 124 to the newly installed switchgear 10 becomes the power outage range BA. In this way, by installing and laying the three boxes 2 to 4 of the newly installed switchgear 10 from the branch duct 124 in advance, the power outage time of the first bank A can be reduced.

Subsequently, as shown in FIG. 5, the two distribution lines connected to the first distribution box 104A of the existing switchgear 100A are switched. That is, the power distribution line is disconnected from the first power distribution line box 104A and connected to the first power distribution line box 4 of the newly installed switchgear 10. At this time, in addition to the power outage range BA in FIG. 4, the first distribution box 104A of the existing switchgear 100A becomes the power outage range BA. Here, the reason why the distribution line of the first distribution line box 104A is switched preferentially is because the distribution line connected to the first distribution line box 104A is more important (important) than other distribution lines. (because it is a load line). That is, when replacing distribution boxes 104A to 106A, priority is given to distribution boxes 104A to 106A to which distribution lines with high importance are connected, not only in the accessory box replacement step described later but also in the essential box installation step. replace.

Next, as shown in FIG. 6, the conductor in the branch duct 124 is connected to the conductor in the duct 123, and the newly installed switchgear 10 is connected in parallel with the existing switchgear 100A to the first transformer 121A, that is, the first Connect to bank A of At this time, the area including the primary circuit breaker 131 and secondary circuit breaker 132 of the first transformer 121A, the busbar communication circuit breaker 133, and the newly installed switchgear 10, and the first distribution box 104A are within the power outage range BA. becomes.

Subsequently, as shown in FIG. 7, the bank power outage is restored, the two distribution lines connected to the first distribution box 4 of the newly installed switchgear 10 are put into operation, and the existing switchgear 100A and the newly installed switchgear 100A are connected to each other. The switchgear 10 is operated in parallel. At this time, the secondary circuit breaker 132 connected to the distribution secondary box 102A is used for bank A and bank B in parallel.

Next, as an accessory box replacement step, the accessory box of the existing switchgear 100A is removed from the foundation 110, and the accessory box of the newly installed switchgear 10 is installed on the foundation 110 and connected to the first transformer 121A. At this time, the number of accessory boxes to be removed from the foundation 110 and the number of accessory boxes to be installed on the foundation 110 in one power outage are set so that the removal can be done within the allowable power outage time.

Specifically, considering the size of the foundation 110, the allowable power outage time, and the required work time, first, the interconnection line 122 is disconnected from the bus box 101A of the existing switchgear 100A, and as shown in FIG. One accessory box of the switchgear 100A, that is, the main box 101A, is removed from the foundation 110, and the distribution boxes 5 and 6 of the newly installed switchgear 10 are installed on the foundation 110. Here, for example, if it is not possible to remove the old accessory box from the foundation 110 and install a new accessory box on the foundation 110 due to one power outage, the old accessory box can be removed and the new accessory box installed. It may be done during different power outages. Further, preparation steps (for example, removal of installation bolts, cable terminal processing, etc.) may be performed before the power outage so that the old accessory box can be removed and the new accessory box installed in a single power outage.

Next, as shown in FIG. 9, the distribution lines are disconnected from the second distribution box 105A and the third distribution box 106A of the existing switchgear 100A, and the distribution lines are removed from the second distribution box 5 of the newly installed switchgear 10. and is connected to the third distribution box 6. At this time, the area including the secondary circuit breaker 132 of the first transformer 121A, the existing switchgear 100A, the distribution boxes 5 and 6 of the newly installed switchgear 10, and the motherboard box 101B of the second bank B is out of power. The range will be BA.

Subsequently, an essential box removal step of removing the essential box of the existing switchgear 100A from the foundation 110 is performed at the same time as the accessory box replacement step. That is, as shown in FIG. 10, all the remaining boxes 102A to 106A of the existing switchgear 100A are removed from the foundation 110, and the mother chain/SC box 1 of the newly installed switchgear 10 is installed on the foundation 110. Next, as shown in FIG. 11, the interconnection line 122 is connected to the bus link/SC box 1 of the newly installed switchgear 10. At this time, the primary side circuit breaker 131 and the secondary side circuit breaker 132 of the first transformer 121A, the busbar communication circuit breaker 133, the existing switchgear 100A, the newly installed switchgear 10, and the second bank B bus box The area including 101B becomes the power outage range BA. Here, the terminal on the side of the newly installed switchgear 10 of the interconnection line 122 is transferred from the existing interconnection box 101A to the newly installed interconnection box by performing terminal processing (processing excluding terminal compression) in the tunnel in advance. To shorten power outage time by switching to SC box 1 in a short time. Then, as shown in FIG. 12, the switching to the newly installed switchgear 10 is completed.

In this way, in the accessory box replacement step, the newly installed distribution boxes 5 and 6 are installed and connected to the foundation 110 at the same time, but depending on the allowable power outage time, etc., the distribution boxes 5 and 6 are installed and connected sequentially. May be connected. In this case, priority is given to replacing the distribution boxes 5 and 6 to which distribution lines with high importance are connected. For example, if a more important distribution line is connected to the second distribution box 105A than to the third distribution box 106A, first remove the existing bus box 101A from the foundation 110, A newly installed second distribution line box 5 is installed on the foundation 110, and a distribution line is connected to the newly installed second distribution line box 5. Next, a newly installed third distribution line box 6 is installed on the foundation 110, and a distribution line is connected to the newly installed third distribution line box 6. In this way, by preferentially replacing the second distribution line box 5 to which the distribution line with high importance is connected, the distribution line with high importance can be opened early, and the distribution lines 5 and 6 can be replaced with priority. It becomes possible to reduce the impact of power outages associated with replacement.

In addition, all the remaining boxes 102A to 106A of the existing switchgear 100A are simultaneously removed from the foundation 110 by performing the essential box removal step and the incidental box replacement step at the same time. The steps may be performed sequentially depending on the time or the like. For example, in the case of the arrangement order shown in FIG. 13, the required box installation step is to install the newly installed secondary distribution box 2, in-house GPT box 3, and first distribution box 4 in the surplus space 111, and The distribution line of the first distribution line box 104A is connected to the newly installed first distribution line box 4. Next, the existing first distribution box 104A is removed, a newly installed second distribution box 5 is installed on the foundation 110, and the distribution lines of the existing second distribution box 105A are transferred to the newly installed second distribution box 105A. Connect to the distribution box 5. Similarly, the existing second distribution box 105A is removed, a newly installed third distribution box 6 is installed on the foundation 110, and the distribution lines of the existing third distribution box 106A are transferred to the newly installed third distribution box 106A. It is connected to the distribution line box 6 and the existing third distribution line box 106A is removed.

As described above, according to this switchgear replacement method, the distribution secondary boxes 2, etc. of the newly installed switchgear 10 are installed in the surplus space 111 of the foundation 110, and the distribution boxes 4 to 6, etc. are installed on the same foundation 110. In order to replace the accessory boxes such as 104A to 106A and remove the essential boxes such as the secondary box 102A of the existing switchgear 100A, it is possible to replace the switchgear without installing a new foundation. Become. Therefore, construction costs associated with installing a new foundation can be reduced, and even if there is no installation space or the foundations of other equipment interfere, it is possible to properly replace the switchgear.

Furthermore, since as many accessory boxes as can be replaced within the allowable power outage time for one power outage operation are sequentially replaced, it is possible to reduce the effects of power outages associated with replacement of accessory boxes.

Furthermore, since distribution boxes 4 to 6 and 104A to 106A to which highly important distribution lines are connected are replaced on a priority basis, the impact of power outages associated with the replacement of distribution boxes 4 to 6 and 104A to 106A can be reduced. becomes possible. In particular, in this embodiment, in the essential box installation step, not only the essential boxes but also the first distribution line box 4 to which highly important distribution lines are connected are installed in the surplus space 111 to install two distribution lines. After the operation begins, the existing switchgear 100A and the newly installed switchgear 10 are operated in parallel, making it possible to minimize the impact of power outages on heavy-load lines.

Although the embodiments of this invention have been described above, the specific configuration is not limited to the above embodiments, and even if there are changes in the design within the scope of the gist of this invention, Included in invention. For example, in the above embodiment, in the essential box installation step, the newly installed secondary distribution box 2, the in-house GPT box 3, and the first distribution line box 4 are installed in the surplus space 111. Only the newly installed secondary distribution box 2 and the in-house GPT box 3 may be installed and connected depending on the size of the power outage, the allowable power outage time, etc. In this case, the first distribution line box 4 is installed and connected in the accessory box replacement step.

Further, the configuration and arrangement order of the boxes 101A to 106A of the existing switchgear 100A, and the structure and arrangement order of the boxes 1 to 6 of the newly installed switchgear 10 are not limited to those described above. Therefore, the order in which boxes 1 to 6 and 101A to 106A are replaced is not limited to the above. Furthermore, although the case where the surplus space 111 is located next to the existing switchgear 100A has been described, the surplus space 111 may be located on the back side of the existing switchgear 100A. Further, if there is no surplus space 111, a space 111 in which an essential box can be installed may be added.

10 Newly installed switchgear 1 Mother chain/SC box (attached box)
2 Secondary distribution box (required box)
3 In-house GPT (required box)
4-6 Distribution line box (attached box)
100A Existing switchgear 101A Mother box (attached box)
102A Secondary change box (required box)
103A Internal GPT box (required box)
104A to 106A Distribution box (attached box)
110 Foundation 111 Surplus space 121A First transformer

Claims (4)

A switchgear replacement method in which an existing switchgear comprising an essential box including a secondary distribution box and an accessory box including a distribution box is installed on a foundation, and the existing switchgear is replaced with a newly installed switchgear. And,
an essential box installation step of installing at least an essential box of the newly installed switchgear in the surplus space of the foundation and connecting it to a transformer in parallel with the existing switchgear;
an accessory box replacement step of removing the existing switchgear accessory box from the foundation, installing the new switchgear accessory box on the foundation, and connecting it to the transformer;
an essential box removal step of removing the existing switchgear essential box from the foundation;
A switchgear replacement method characterized by comprising: In the auxiliary box replacement step, the number of auxiliary boxes to be removed from the foundation and the number of auxiliary boxes to be installed on the foundation in one power outage are set so that the removal can be done within the allowable power outage time.
The switchgear replacement method according to claim 1, characterized in that: In the essential box installation step and the accessory box replacement step, a distribution line box to which a distribution line of high importance is connected is replaced with priority;
The switchgear replacement method according to claim 1 or 2, characterized in that: In the essential box installation step, installing a distribution line box of the newly installed switchgear in the surplus space and connecting it to the transformer;
The switchgear replacement method according to any one of claims 1 to 3, characterized in that:

Images