A power supply automatic switching control circuit

Abstract

The present invention belongs to the field of power supply technology applications and relates to a power backup automatic re-start control circuit, comprising a DC power supply positive electrode +KM, a Q1 control circuit, a Q2 control circuit, a Q automatic re-start control circuit, and a DC power supply negative electrode -KM. The DC power supply positive electrode +KM is connected in parallel to the Q1 control circuit, the Q2 control circuit, and the Q automatic re-start control circuit, returning to the DC power supply negative electrode -KM to form a circuit. This invention is simple to implement and has low investment costs. In the event of a power failure due to a distribution transformer fault or a power line fault, if both the "distribution transformer low-voltage relay kV voltage loss" and the "distribution transformer low-voltage side circuit breaker tripping" conditions are met, the low-voltage bus tie circuit breaker Q backup automatic re-start automatically switches on, ensuring safe, continuous, and stable power supply to the power supply system.

Description

Technical Field

[0001] The invention belongs to the technical field of power supply technology application, and in particular relates to a power supply standby automatic switching control circuit. Background Art

[0002] In order to improve the reliability of power supply, most of the more important high-voltage distribution users are powered by two power sources. When the high-voltage power supply and distribution system is in normal power supply operation, the 10kVⅠ incoming line supplies power to the 0.4kV low-voltage bus W1 through the distribution transformer (hereinafter referred to as distribution transformer) T1, and the 10kVⅡ incoming line supplies power to the 0.4kV low-voltage bus W2 through the distribution transformer T2. The 10kVⅠ and Ⅱ section bus tie circuit breakers are QF for hot standby, and the 0.4kV low-voltage bus W1 and W2 bus tie circuit breakers are Q for hot standby, and other circuit breakers are all closed for operation.

[0003] When the 10kV I (or II) incoming line loses power or distribution transformer T1 (or T2) fails, all loads on the 0.4kV low-voltage busbar W1 (or W2) lose power. It is necessary to disconnect the low-voltage circuit breaker on distribution transformer T1 (or T2) and close the 0.4kV low-voltage busbar tie breaker. This will cause a power outage for the user loads on the 0.4kV low-voltage busbar W1 (or W2) for a period of time, affecting power supply reliability. Therefore, to improve the reliability of equipment power supply operation, it is necessary to provide a power supply backup automatic transfer control circuit. Summary of the Invention

[0004] The object of the present invention is to provide a power supply standby automatic switching control circuit. When a distribution transformer fails or its power line fails, and the two conditions of "distribution transformer low-voltage relay kV voltage loss" and "distribution transformer low-voltage side circuit breaker tripping" are met, the low-voltage bus tie circuit breaker Q standby automatic switching will be automatically switched on, ensuring safe, continuous and stable power supply to the power supply system, thereby solving the problem of power outage for user loads of the 0.4kV low-voltage bus W1 (or W2) in the prior art for a period of time.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is as follows: the present invention provides a power supply automatic transfer control circuit, including a DC power supply positive electrode +KM, a Q1 control circuit, a Q2 control circuit, a Q automatic transfer control circuit, and a DC power supply negative electrode -KM, wherein the DC power supply positive electrode +KM is connected in parallel to the Q1 control circuit, the Q2 control circuit, and the Q automatic transfer control circuit and returns to the DC power supply negative electrode -KM to form a loop;

[0006] The Q1 control circuit includes a group of contacts of the automatic switching device linkage switch SA1 of the T1 low-voltage circuit breaker Q1, the first normally closed contact KV11 of the low-voltage relay KV1, the auxiliary normally open contact of the low-voltage circuit breaker Q1, the time relay KT1, and the closing coil HQ1 of the low-voltage circuit breaker Q1; the Q2 control circuit includes a group of contacts of the automatic switching device linkage switch SA2 of the T2 low-voltage circuit breaker Q2, the first normally closed contact KV21 of the low-voltage relay KV2, the auxiliary normally open contact of the low-voltage circuit breaker Q2, and Time relay KT2, closing coil HQ2 of low-voltage circuit breaker Q2; the Q automatic-closing control circuit includes the first and second sets of contacts of the linkage switch SA of the automatic-closing device of the low-voltage bus tie circuit breaker Q, the second normally closed contact KV12 of the low-voltage relay KV1, the second normally closed contact KV22 of the low-voltage relay KV2, the auxiliary normally closed contact of the low-voltage circuit breaker Q1, the auxiliary normally closed contact of the low-voltage circuit breaker Q2, and the auxiliary normally closed contact of the low-voltage bus tie circuit breaker Q, and the closing coil HQ of the low-voltage bus tie circuit breaker Q.

[0007] Furthermore, a group of contacts of the automatic-throwing device linkage switch SA1 of the T1 low-voltage circuit breaker Q1 includes contact a1 and contact b1, a group of contacts of the automatic-throwing device linkage switch SA2 of the T2 low-voltage circuit breaker Q2 includes contact a2 and contact b2, the first group of contacts of the automatic-throwing device linkage switch SA of the low-voltage bus tie circuit breaker Q includes contact a and contact b, the second group of contacts of the automatic-throwing device linkage switch SA of the low-voltage bus tie circuit breaker Q includes contact c and contact d, the time relay KT1 includes the coil of the time relay KT1 and its normally open contact with delayed closure, and the time relay KT2 includes the coil of the time relay KT2 and its normally open contact with delayed closure.

[0008] Furthermore, the contact b1 of a group of contacts of the automatic-closing device linkage switch SA1 of the T1 low-voltage circuit breaker Q1 is connected to the first normally closed contact KV11 of the low-voltage relay KV1, and the first normally closed contact KV11 of the low-voltage relay KV1 is connected in parallel with the auxiliary normally open contact of the low-voltage circuit breaker Q1 connected in series with the coil of the time relay KT1 and the delayed closing normally open contact of the time relay KT1 connected in series with the closing coil HQ1 of the low-voltage circuit breaker Q1.

[0009] Furthermore, the contact b2 of a group of contacts of the automatic-closing device linkage switch SA2 of the T2 low-voltage circuit breaker Q2 is connected to the first normally closed contact KV21 of the low-voltage relay KV2, and the first normally closed contact KV21 of the low-voltage relay KV2 is connected in parallel with the auxiliary normally open contact of the low-voltage circuit breaker Q2, which is connected in series with the coil of the time relay KT2 and the delayed closing normally open contact of the time relay KT2, which is connected in series with the closing coil HQ2 of the low-voltage circuit breaker Q2.

[0010] Furthermore, the series connection of the contact b of the first group of contacts of the automatic-closing device linkage switch SA of the low-voltage bus tie circuit breaker Q and the second normally closed contact KV12 of the low-voltage relay KV1 and the auxiliary normally closed contact of the low-voltage circuit breaker Q1, and the series connection of the contact d of the second group of contacts of the automatic-closing device linkage switch SA of the low-voltage bus tie circuit breaker Q and the second normally closed contact KV22 of the low-voltage relay KV2 and the auxiliary normally closed contact of the low-voltage circuit breaker Q2 are connected in parallel to the auxiliary normally closed contact of the low-voltage bus tie circuit breaker Q, and the auxiliary normally closed contact of the low-voltage bus tie circuit breaker Q is connected to the closing coil HQ of the low-voltage bus tie circuit breaker Q.

[0011] Furthermore, the operating voltage of the DC power supply is 220V.

[0012] Furthermore, the DC power supply positive electrode +KM and the DC power supply negative electrode -KM are configured with a DC circuit breaker.

[0013] Compared with the prior art, the advantages and positive effects of the present invention are:

[0014] 1. The present invention is simple and feasible to implement, with low investment cost;

[0015] 2. The present invention can realize that when two high-voltage incoming power sources or distribution transformer (T1 or T2) lose power, the low-voltage bus tie circuit breaker Q can be automatically put into operation to ensure reliable operation of the power supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 This is a primary wiring diagram of a typical dual power supply and distribution system in the prior art;

[0018] Figure 2 A primary wiring diagram of a power supply automatic switching control circuit provided in an embodiment;

[0019] Figure 3 A circuit diagram of a power supply automatic switching control circuit provided in an embodiment; DETAILED DESCRIPTION

[0020] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features therein can be combined with each other.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] like Figure 1 As shown, in a typical dual-power supply and distribution system in the prior art, when the 10kV power supply and distribution system is operating normally, the 10kVⅠ incoming line supplies power to the 0.4kV low-voltage bus W1 and its load through the distribution transformer (hereinafter referred to as distribution transformer) T1 and the circuit breaker Q1, and the 10kVⅡ incoming line supplies power to the 0.4kV low-voltage bus W2 and its load through the distribution transformer T2 and the circuit breaker Q2. The 10kVⅠ and Ⅱ section bus tie circuit breaker QF is in hot standby mode, the 0.4kV low-voltage bus W1 and W2 bus tie circuit breaker Q is in hot standby mode, and the other circuit breakers are all closed for operation. When the 10kV I (or II) incoming line loses power or distribution transformer T1 (or T2) fails, all loads on the 0.4kV low-voltage busbar W1 (or W2) lose power. At this point, the low-voltage circuit breaker on distribution transformer T1 (or T2) must be disconnected and the 0.4kV low-voltage busbar tie breaker closed. This will cause a power outage for the user loads on the 0.4kV low-voltage busbar W1 (or W2) for a period of time, affecting power supply reliability. Therefore, a power backup automatic transfer control circuit is required.

[0023] Examples, such as Figure 2-3 As shown, a power supply standby automatic transfer control circuit corresponds to the automatic transfer devices of the low-voltage circuit breaker Q1, the low-voltage circuit breaker Q2 and the low-voltage bus tie circuit breaker Q on the low-voltage side of the distribution transformer T1 and the distribution transformer T2, respectively, which are installed on the automatic transfer cabinet and are controlled by a group of contacts of the linkage switch SA1 of the automatic transfer device of the low-voltage circuit breaker Q1 of T1, a group of contacts of the linkage switch SA2 of the automatic transfer device of the low-voltage circuit breaker Q2 of T2, and the first group of contacts and the second group of contacts of the linkage switch SA of the automatic transfer device of the low-voltage bus tie circuit breaker Q.

[0024] Under normal power supply operation, the automatic transfer device linkage switch SA1 of the T1 low-voltage circuit breaker Q1 is set to the "3" position, indicating that the circuit breaker is in the "automatic transfer and automatic reset" position. At this time, contacts a1 and b1 of a group of contacts of the automatic transfer device linkage switch SA1 of the T1 low-voltage circuit breaker Q1 are connected; the automatic transfer device linkage switch SA2 of the T2 low-voltage circuit breaker Q2 is set to the "3" position, indicating that the circuit breaker is in the "automatic transfer and automatic reset" position. At this time, contacts b1 and b2 of a group of contacts of the automatic transfer device linkage switch SA2 of the T2 low-voltage circuit breaker Q2 are connected; the automatic transfer device linkage SA of the low-voltage bus tie circuit breaker Q is set to the "3" position, indicating that the circuit breaker is in the "automatic transfer and automatic reset" position. At this time, contacts a and b of the first group of contacts of the automatic transfer device linkage switch SA of the low-voltage bus tie circuit breaker Q are connected, and contacts c and d of the second group of contacts of the automatic transfer device linkage switch SA of the low-voltage bus tie circuit breaker Q are connected.

[0025] During normal power supply operation, all automatic transfer devices are set to position "3." Distribution transformers T1 and T2 operate with 0.4kV low-voltage busbars W1 and W2 via circuit breakers Q1 and Q2, respectively. 10kV bus tie breaker QF and 0.4kV system bus tie breaker Q are in hot standby mode, and all other circuit breakers are closed. At this point, the coil of distribution transformer T1's low-voltage relay KV1 is energized, its first normally closed contact KV11 opens, and the auxiliary normally open contact of distribution transformer T1's low-voltage circuit breaker Q1 closes, while the auxiliary normally closed contact of low-voltage circuit breaker Q1 opens. Distribution transformer T2's low-voltage relay KV2 is energized, its first normally closed contact KV21 opens, and the auxiliary normally open contact of distribution transformer T2's low-voltage circuit breaker Q2 closes, while the auxiliary normally closed contact of low-voltage circuit breaker Q2 opens.

[0026] When the distribution transformer T1 fails and loses power or its 10kVⅠ incoming power line fails and loses power, the coil of the low-voltage relay KV1 of the distribution transformer T1 loses power, the first normally closed contact KV11 of the low-voltage relay KV1 returns to close and connects, the coil of the time relay KT1 is energized, and after a certain time delay, the closing coil HQ1 of the low-voltage circuit breaker Q1 of the distribution transformer T1 is energized, and the low-voltage circuit breaker Q1 of the distribution transformer T1 trips; the auxiliary normally closed contact of the low-voltage circuit breaker Q1 The contacts return to a closed position. Since the bus tie circuit breaker is in the open position and the auxiliary normally closed contact of bus tie circuit breaker Q is in the closed position, the DC power supply's positive terminal, +KM, connects the circuit to the closing coil HQ of low-voltage bus tie circuit breaker Q via the first set of contacts a and b of the automatic switching device linkage switch SA of low-voltage bus tie circuit breaker Q. This energizes the closing coil HQ of low-voltage bus tie circuit breaker Q, automatically closing low-voltage bus tie breaker Q and placing it into operation, supplying busbar W1. Therefore, when both the "low-voltage relay kV voltage loss on distribution transformer T1" and the "low-voltage side circuit breaker tripping on distribution transformer T1" conditions are met, the backup automatic switching device of low-voltage bus tie breaker Q automatically switches into operation, and the 10kV II incoming line and distribution transformer T2, via the 0.4kV low-voltage bus tie breaker Q, supply all loads on low-voltage busbar W1, ensuring safe, continuous, and stable power supply to the entire power supply system.

[0027] When the low-voltage circuit breaker Q1 of distribution transformer T1 trips alone due to a 0.4kV low-voltage W1 busbar fault, since distribution transformer Tl and low-voltage relay KV1 are still energized and running, the conditions for the standby automatic transfer of the low-voltage side busbar circuit breaker Q are not met, and the low-voltage side busbar circuit breaker Q will not be automatically transferred. This avoids the expansion of the accident scope caused by the automatic transfer of the standby automatic transfer when the W1 busbar fails.

[0028] The working principle of the standby automatic transfer when the distribution transformer T2 fails or the power line fails is the same as above.

[0029] The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0030] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A power supply automatic switching control circuit, characterized in that: It includes the DC power supply positive electrode +KM, Q1 control circuit, Q2 control circuit, Q automatic transfer control circuit and DC power supply negative electrode -KM. The DC power supply positive electrode +KM is connected to the parallel connection of Q1 control circuit, Q2 control circuit and Q automatic transfer control circuit back to the DC power supply negative electrode -KM to form a loop; The Q1 control circuit includes a group of contacts of the automatic switching device linkage switch SA1 of the T1 low-voltage circuit breaker Q1, the first normally closed contact KV11 of the low-voltage relay KV1, the auxiliary normally open contact of the low-voltage circuit breaker Q1, the time relay KT1, and the closing coil HQ1 of the low-voltage circuit breaker Q1; the Q2 control circuit includes a group of contacts of the automatic switching device linkage switch SA2 of the T2 low-voltage circuit breaker Q2, the first normally closed contact KV21 of the low-voltage relay KV2, the auxiliary normally open contact of the low-voltage circuit breaker Q2, and Time relay KT2, closing coil HQ2 of low-voltage circuit breaker Q2; the Q automatic-closing control circuit includes the first and second sets of contacts of the linkage switch SA of the automatic-closing device of the low-voltage bus tie circuit breaker Q, the second normally closed contact KV12 of the low-voltage relay KV1, the second normally closed contact KV22 of the low-voltage relay KV2, the auxiliary normally closed contacts of the low-voltage circuit breaker Q1, the auxiliary normally closed contacts of the low-voltage circuit breaker Q2, and the auxiliary normally closed contacts of the low-voltage bus tie circuit breaker Q, and the closing coil HQ of the low-voltage bus tie circuit breaker Q; A group of contacts of the automatic-throwing device linkage switch SA1 of the T1 low-voltage circuit breaker Q1 includes contact a1 and contact b1, a group of contacts of the automatic-throwing device linkage switch SA2 of the T2 low-voltage circuit breaker Q2 includes contact a2 and contact b2, a first group of contacts of the automatic-throwing device linkage switch SA of the low-voltage bus tie circuit breaker Q includes contact a and contact b, a second group of contacts of the automatic-throwing device linkage switch SA of the low-voltage bus tie circuit breaker Q includes contact c and contact d, the time relay KT1 includes the coil of the time relay KT1 and its normally-open contact with delayed closure, and the time relay KT2 includes the coil of the time relay KT2 and its normally-open contact with delayed closure; The contact b1 of a group of contacts of the automatic-closing device linkage switch SA1 of the T1 low-voltage circuit breaker Q1 is connected to the first normally closed contact KV11 of the low-voltage relay KV1, and the first normally closed contact KV11 of the low-voltage relay KV1 is connected to the auxiliary normally open contact of the low-voltage circuit breaker Q1 in series with the coil of the time relay KT1 and the delayed closing normally open contact of the time relay KT1 in series with the closing coil HQ1 of the low-voltage circuit breaker Q1 in parallel.

2. A power supply automatic switching control circuit according to claim 1, characterized in that: The contact b2 of a group of contacts of the automatic-closing device linkage switch SA2 of the T2 low-voltage circuit breaker Q2 is connected to the first normally closed contact KV21 of the low-voltage relay KV2, and the first normally closed contact KV21 of the low-voltage relay KV2 is connected to the auxiliary normally open contact of the low-voltage circuit breaker Q2 in series with the coil of the time relay KT2 and the delayed closing normally open contact of the time relay KT2 in series with the closing coil HQ2 of the low-voltage circuit breaker Q2 in parallel.

3. A power supply automatic switching control circuit according to claim 1, characterized in that: The contact b of the first group of contacts of the automatic-closing device linkage switch SA of the low-voltage bus tie circuit breaker Q is connected in series with the second normally closed contact KV12 of the low-voltage relay KV1 and the auxiliary normally closed contact of the low-voltage circuit breaker Q1, and the contact d of the second group of contacts of the automatic-closing device linkage switch SA of the low-voltage bus tie circuit breaker Q is connected in series with the second normally closed contact KV22 of the low-voltage relay KV2 and the auxiliary normally closed contact of the low-voltage circuit breaker Q2, and then connected in parallel to the auxiliary normally closed contact of the low-voltage bus tie circuit breaker Q. The auxiliary normally closed contact of the low-voltage bus tie circuit breaker Q is connected to the closing coil HQ of the low-voltage bus tie circuit breaker Q.

4. A power supply automatic switching control circuit according to claim 1, characterized in that: The operating voltage of the DC power supply is 220V.

5. A power supply automatic switching control circuit according to claim 1, characterized in that: The DC power supply positive electrode +KM and the DC power supply negative electrode -KM are configured with a DC circuit breaker.

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