JPS62233026A - Bus-bar system of distribution equipment - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a bus system in power distribution equipment in factories, buildings, etc., and particularly relates to a bus system in power distribution equipment that accommodates an increase in the capacity of power distribution equipment. .

[Conventional technology]

Busbar systems for power distribution equipment in factories, buildings, etc. are based on the following system, which is a compromise between the need for reduced equipment costs and multi-functionality. From two distribution transformers equipped with protective circuit breakers on the secondary side, the equipment load capacity is equally distributed by a distribution bus section breaker, and the distribution lines are connected to the distribution buses of two systems A and B, and In order to prevent short-circuit currents from summing up the two distribution transformers, an interlock is installed between each circuit breaker that allows up to two circuit breakers to be closed at the same time depending on the operating conditions of the equipment.

This puts a heavy load on air conditioning and cooling equipment depending on the season.

In response to large load fluctuations, such as light loads, stoppages, and power and lighting equipment during the day, heavy loads during the day and light loads only for maintenance and disaster prevention equipment during the night, energy-saving operation measures can be taken to increase the operating load capacity f4. The intersection of the two-way loss curve, which is the sum of the iron loss and copper loss of one transformer and the sum of the iron loss and copper loss of two transformers, is taken as the branching point for energy-saving operation. Perform parallel operation. In addition, in order to minimize the downtime due to failure or maintenance inspection of one transformer or one of the distribution busbars of A and B, in order to prevent production decline and stoppage, and to prevent loss of disaster prevention and security power supply, This is to enable operation in such a way as to select only the important loads corresponding to the situation in case of an accident, and to escape from the abnormal situation by driving with one lung.

On the other hand, the capacity of the above-mentioned power distribution equipment has been increasing significantly in recent years, and the power receiving system is also increasing from extra high voltage of 20KV to 60KV.
A method is adopted in which power is distributed directly to low voltage using a distribution transformer.
The single transformer capacity is as high as 5MVA, and the electrical path to the distribution bus has a very large current and short circuit current. Then, the rated current is 7217A
, the short circuit current is 72171A, and in order to cope with the conventional busbar system of power distribution equipment, the transformer, circuit breaker, closed switchboard that houses the circuit breaker and its operation protection device, which specifically forms the power distribution equipment, and the transformer and closed switchboard For bus ducts that connect electrical conductors, it is necessary to take measures to strengthen resistance heat loss in the conductor due to the carrying current, heat generation due to eddy current in steel structures surrounding the conductor, mechanical strength due to short circuit current, and the breaking current capacity of the circuit breaker. Therefore, there was a limit to the capacity of the equipment. Note that Japanese Patent Publication No. 54-40298 is related to this type of system.

[Problem that the invention seeks to solve]

According to the above-mentioned conventional method, both distribution buses of A and B receive centralized power supply from a transformer from one point, so there is a limit to the use of conventional standard equipment to support new equipment with increased capacity, and there are limits to the use of conventional standard equipment such as transformers and closed distribution boards. , circuit breaker.

It is necessary to develop special new design quantities for bus ducts, etc., and new production and assembly jigs and tools that are used infrequently in the manufacturing process must be installed, making it impossible to put them on a normal manufacturing line. Furthermore, after assembly, it is necessary to verify performance by conducting current-carrying temperature rise tests, short-time current tests, breaking current tests, etc., which dramatically increases the manufacturing price including development costs. There was a problem in that it was not possible to meet short delivery times due to the lengthening of lead times.Furthermore, when increasing the capacity of existing equipment, all of the equipment up to the distribution busbars lacked current-carrying capacity, making it impossible to reuse it at all. There were no problems.

The purpose of the present invention is to use the existing standard equipment that has been used in the past, without having to develop or use any new design, and to increase the capacity of the existing equipment even if the installed capacity exceeds the actual installed capacity up to now. The goal is to make it possible to reuse existing equipment.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention is designed to connect the secondary windings of the transformers that feed power from the transformers via the protective circuit breakers to the distribution buses of two systems, A and B, which are separated by circuit breakers and have distribution lines attached to them. One of the two electrically equally separated and independent sets common to the
Connect one set to the terminal of the distribution bus A and the other set to the center point of the load capacity distribution of the distribution bus B, and connect one of the two sets of secondary windings of the transformer.
By connecting one set to the center point of the load capacity distribution of the distribution bus A and the other set to the terminal of the distribution bus B, this can be done by constantly distributing power from the transformer to two points on both distribution buses. The purpose is achieved.

[Effect]

In this way, the load is equally distributed between two transformers with two sets of secondary windings and a sectional circuit breaker, and by connecting two distribution buses with distribution lines according to the present invention, one ordinary transformer can be created. 2
When operating at full load capacity, the bus divisional circuit breaker is used, and the distribution bus A and B is separated into two systems, so the short circuit current of the two transformers is not added up, and the distribution bus A and B has two transformers. The power is more evenly supplied, and the power supply points from the transformer receive divided power evenly from the terminal and the center point of load capacity distribution for both distribution buses, so the bus current carrying capacity is equal to the transformer secondary winding AI2. The current capacity of one of the sets may be sufficient, that is, the current capacity of the entire installed capacity may be 174.

[Embodiments] Hereinafter, five embodiments of the present invention will be explained with reference to the busbar system of power distribution equipment shown in the figure.

In FIG. 1, distribution transformers 1 and 2 are two electrically independent and equally distributed systems, and the secondary winding (1a.

lb) and (2a, 2b) are protective circuit breakers 3a and 3, respectively.
Distribution f where the load is evenly distributed to each of the two systems by the bus section circuit breaker 4 which operationally divides the installed capacity into two through lines b, 3c, and 3d! ! ! 7 A distribution bus 5 with A and 7B attached
The secondary winding 1a of the transformer 1 is connected to the distribution bus terminal A through a protective circuit breaker 3a, and
The secondary winding 2a of the transformer 2 is connected to the center point of load capacity distribution of the first distribution bus 5 via a protective circuit breaker 3b. Similarly, the secondary winding 2b of the transformer 2 is connected to the terminal of the distribution bus 6 through the protective circuit breaker 3d, and the secondary winding 1b of the transformer 1 is connected to the terminal of the distribution bus 6 through the circuit breaker 3c. Connect to the center point of load capacity distribution. The load capacity classification of the A and B distribution buses 5.6 is such that the protective circuit breakers 3b and 3c are separated at locations where the load capacities of multiple fuses 8 and load-side circuit breakers 9 are equal within each distribution bus.
Connect.

Distribution bus section breaker 4 and protective circuit breakers 3a and 3b.

An interlock is provided between 3c and 3a to prevent short-circuit currents from being added up due to parallel operation of both pressure regulators.

In this bus system, in addition to being able to operate two transformers in parallel during normal full load, when stopping distribution transformer 1,
Turn off the protective circuit breakers 3a and 3c, and manually operate the protective circuit breaker 4 by limiting the load on both the A distribution bus 5 and the O distribution bus 6, or either the A distribution bus 5 or the O distribution bus 6. can be operated with the capacity of one transformer through the sectional circuit breaker 4. Furthermore, in order to stop the power distribution bus on one side, for example, the first distribution bus 5, the protective circuit breakers 3a, 3b, and 4 are turned off, and the transformer 2
One set of secondary windings lb and 2b are connected to the protective circuit breaker 3c from the stand.
, 3d, it is possible to operate the O distribution bus 6 side.

Furthermore, the above-mentioned points will be specifically explained. For example, (1) When feeding and distributing 50% of the rated current to the A and B distribution buses, the distribution transformer 1 and protective circuit breakers 3a and 3c are turned off, and the sectional circuit breaker 4 is turned on. Secondary winding 2 of device 2
The rated currents of a and 2b are supplied at 50 (%) each to the A distribution bus s5 and the B distribution bus 6 via the protective circuit breakers 3b and 3d. In other words, rated currents of 50% each flow through the protective circuit breakers 3b and 3d.

(2) When supplying and distributing the rated current at 100% (%) only to the distribution bus 6 A The rated current of 2b and 2b is supplied to and distributed to the first power distribution buses 5A and 5B via the protective circuit breaker 3b, the protective circuit breaker 3d, and the sectional circuit breaker 4 at a rate of 50 (%).

In addition, in the above state, the rated current to the first distribution bus 6 is set to O(
%), and a rated current of 100 (%) can also be supplied and distributed to the distribution bus 6 via the protective circuit breaker 3b, the sectional circuit breaker 4, and the protective circuit breaker 3d.

(3) When supplying and distributing the rated current at 100% (%) only to the distribution bus 6, with the protective circuit breakers 3a, 3b and the sectional circuit breaker 4 turned off,
The rated current from the secondary lb, 2b is the protective circuit breaker 3c, 3
50(%) each of power is supplied and distributed to the first distribution bus 6A and 6B via d.

(4) Set the rated current to 100 (
%) When supplying and distributing power, with the sectional circuit breaker 4 turned off, connect the secondary windings 1a to lb, 2.
The rated current from a to 2b is fed and distributed to the distribution buses 5A to 5B and 6A to 6B via the protective circuit breakers 3a to 3b at a rate of 50(%).

As described above, according to the present invention, by adding the protective circuit breakers 3b and 3c to the conventional power distribution equipment, the capacity of the conventional power distribution equipment can be increased by 2.
It is economical because it can double the installed capacity. Also,
In any distribution system the protective circuit breakers 38 to 3d and the sectional circuit breaker 4.

Since the rated current flows in 50 (%) increments,
A protective circuit breaker with the same performance can be used. As a result, even if one protective circuit breaker fails, another protective circuit breaker can be used for repair. In other words, they are compatible. Furthermore, since it is sufficient to use protective circuit breakers with the same performance, it is economical and easy to store.

〔Effect of the invention〕

As described above, according to the bus system of the power distribution equipment of the present invention,
Equipment capacity can be easily doubled.

[Brief explanation of drawings]

The figure is a busbar system circuit diagram of a power distribution facility according to an embodiment of the present invention. 1.2...Distribution transformer, la, lb, 2a, 2b・-
・Secondary winding, 3a to 3d...protective circuit breaker, 4...section breaker ・50"6゛°A81"B distribution bus・
,・. Agent: Patent attorney Katsuma Ogawa (171, L)

Claims (1)

[Claims] 1. At least one pair of distribution systems each having a first protective circuit breaker connected to the secondary side of the transformer are arranged in parallel, and each distribution system on the protective circuit breaker side is connected by a common distribution bus. A sectional circuit breaker is installed on the distribution bus, and multiple loads are installed on the distribution bus between the sectional breaker and the distribution system on one side and the distribution system on the other side to form a distribution load on one side and a distribution load on the other side. In what I did,
The secondary side of the transformer of the distribution system on one side and the distribution load on the other side are connected via the second protective circuit breaker between the secondary side of the transformer on the distribution system on the other side and the distribution load on the one side. Busbar system of power distribution equipment. 2. The bus system of power distribution equipment according to claim 1, wherein the second protective circuit breaker is connected to a power distribution bus point through which an equal load current flows in each power distribution load.