Standby power automatic switching logic simplification method for single-bus sectional wiring transformer substation powered by four power sources

Abstract

The invention discloses a spare power automatic switching logic simplification method for a single-bus sectional wiring transformer substation powered by four power sources, which is applied to the single-bus sectional wiring transformer substation powered by the four power sources in a 110kV voltage class power transmission and distribution network, and simplifies spare power automatic switching configuration of the single-bus sectional transformer substation powered by the four power sources into a plurality of simple wiring spare power automatic switching devices. The logic algebra expression of the spare power automatic switching device of the single-bus sectional wiring transformer substation powered by four power supplies is # imgabs0 #, so that the configuration operation of the spare power automatic switching device of the single-bus sectional wiring transformer substation powered by four power supplies is realized, and the correctness of the operation mode of the wiring spare power automatic switching device is verified by logic algebra.

Description

Technical Field

[0001] The invention relates to a method for simplifying backup automatic switching logic of a single-busbar sectionalized connection transformer substation powered by four power supplies, belonging to the control technology of power transmission and distribution network. Background Art

[0002] With the continuous construction of power systems, some substations represented by 110kV voltage level adopt more than two power connections. In order to optimize the power supply capacity resources of 110kV substations, some 110kV voltage level substations have four power supply lines. For example, a chain structure network architecture is adopted. The substation incoming line can be taken from multiple different power sources to form a chain structure of "two-end power supply, two-line multi-station". Its operation mode is flexible and changeable. Among them, the 110kV single busbar segmented wiring substation theoretically has four power supplies. If the operation mode of a single substation under this wiring mode is "exhaustively enumerated", there are as many as 27 types. At present, there is no corresponding standby power supply automatic input device protection scheme (hereinafter referred to as standby automatic input) that can meet this wiring mode. Engineering examples have proved that the standby automatic input device of complex wiring can be simplified to several simple wiring standby automatic inputs. However, how to configure and simplify the standby automatic input of a single busbar segmented wiring substation powered by four power sources, and how to verify the correctness of its operation mode, the existing technology has not yet solved. Therefore. It is a technical problem that urgently needs to be studied and solved in this field to study the configuration simplification method of the backup automatic switching of a single-bus sectionalized substation powered by four power sources and use logical algebra methods to verify the correctness of the backup automatic switching operation mode. Summary of the invention

[0003] The purpose of the present invention is to provide a method for simplifying the logic of the automatic switching of a single-busbar segmented wiring substation with four power supplies, which is applied to a 110kV voltage level power transmission and distribution network, a single-busbar segmented wiring substation with four power supplies, and simplifies the automatic switching configuration of the single-busbar segmented wiring substation with four power supplies into several simple wiring automatic switching, so as to realize the configuration operation of the automatic switching of the single-busbar segmented wiring substation with four power supplies, and verify the correctness of the wiring automatic switching operation mode by using logic algebra.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A method for simplifying the logic of a standby automatic switching of a single busbar sectionalized connection substation powered by four power sources, which simplifies the standby automatic switching of a single busbar sectionalized connection substation powered by four power sources into a system consisting of four single busbar sectionalized connection standby automatic switching and two single busbar connection standby automatic switching;

[0006] The circuit breakers QF1, QF2 and QF3 of the single busbar sectionalized wiring substation line powered by four power supplies form a single busbar sectionalized wiring standby automatic switch of three circuit breakers of dual power supplies, referred to as standby automatic switch 1;

[0007] The single mother section wiring standby automatic transfer of the dual power supply three circuit breakers composed of circuit breakers QF3, QF4 and QF5 is referred to as standby automatic transfer 2;

[0008] The single mother section wiring standby automatic switching of the dual power supply three circuit breakers composed of circuit breakers QF1, QF3 and QF5 is referred to as standby automatic switching 3;

[0009] The single mother section wiring standby automatic transfer of the dual power supply three circuit breakers composed of circuit breakers QF2, QF3 and QF4 is referred to as standby automatic transfer 4;

[0010] The single busbar standby automatic transfer of two circuit breakers of dual power supply composed of circuit breakers QF1 and QF4 is referred to as standby automatic transfer 5;

[0011] The single busbar standby automatic transfer of two circuit breakers of dual power supply composed of circuit breakers QF2 and QF5 is referred to as standby automatic transfer 6;

[0012] The operation mode of the standby automatic input 1 satisfies the following logical algebraic expression:

[0013]

[0014] The operation mode of the standby automatic input 2 satisfies the following logical algebraic expression:

[0015]

[0016] The operation mode of the standby automatic input 3 satisfies the following logical algebraic expression:

[0017]

[0018] The operation mode of the standby automatic input 4 satisfies the following logical algebraic expression:

[0019]

[0020] The operation mode of the standby automatic input 5 satisfies the following logical algebraic expression:

[0021]

[0022] The operation mode of the standby automatic input 6 satisfies the following logical algebraic expression:

[0023]

[0024] The logical relationship between the above backup automatic switching is "OR". The logical algebraic expression of the backup automatic switching of the single busbar sectionalized substation with four power supplies is:

[0025]

[0026] Among them, A, B, C, D, and E respectively represent that the circuit breakers QF1, QF2, QF3, QF4, and QF5 are in the closed operating state, and are respectively represented by 1 in logical algebra; Respectively indicate that the circuit breakers QF1, QF2, QF3, QF4, and QF5 are in the open operation state, that is, the hot standby state, and are respectively represented by 0 in logical algebra;

[0027] The logical algebraic expression of each field in the above formula represents an operating mode of a single-bus sectionalized substation powered by four power sources, with a total of 27 operating modes.

[0028] The purpose of the present invention can also be further achieved by the following technical measures:

[0029] The method for simplifying the standby automatic transfer logic of the single-busbar sectionalized connection substation powered by four power sources mentioned above, the control logic of the standby automatic transfer of the single-busbar sectionalized connection substation powered by four power sources is composed of 6 parts, including the single-mother sectionalized connection standby automatic transfer logic composed of high-voltage side circuit breakers QF1, QF2, and QF3, the single-mother sectionalized connection standby automatic transfer logic composed of circuit breakers QF3, QF4, and QF5, the single-mother sectionalized connection standby automatic transfer logic composed of circuit breakers QF2, QF3, and QF4, the single-mother sectionalized connection standby automatic transfer logic composed of circuit breakers QF1, QF3, and QF5, the single-mother sectionalized connection standby automatic transfer logic composed of circuit breakers QF1 and QF4, and the single-mother sectionalized connection standby automatic transfer logic composed of circuit breakers QF2 and QF5, and the 6 parts are arranged in the same standby automatic transfer device.

[0030] The aforementioned simplified method for the backup automatic switching logic of the single-busbar sectionalized connection substation powered by four power sources is to achieve selection by setting an action delay between the six backup automatic switching units when more than one of the six backup automatic switching units meets the action conditions.

[0031] The simplified method of the backup automatic switch logic of the single busbar sectionalized connection substation powered by four power sources mentioned above is to realize the selection by adding judgment logic between the backup automatic switches when more than one of the six backup automatic switches meets the action conditions. For example, the longitudinal backup automatic switch (backup automatic switch 5 and backup automatic switch 6) is used first, or the backup automatic switch priority action related to the priority dedicated power supply is selected in combination with the actual on-site operation situation.

[0032] Compared with the prior art, the present invention achieves the following beneficial effects:

[0033] 1. The standby automatic switching unit of a single-busbar sectionalized substation with four power supplies is simplified to consist of four dual-power single-busbar sectionalized primary main wiring standby automatic switching units and two dual-power single-busbar standby automatic switching units, which is simple and clear.

[0034] 2. After simplification, the single-busbar sectionalized connection substation with four power supplies can automatically adapt to the input or output according to the operating status of the primary equipment, and some backup automatic input functions can be enabled, with strong operational flexibility.

[0035] 3. Several simple backup automatic starters that are simplified from the backup automatic starter logic of a single-busbar sectionalized wiring substation powered by four power sources are common backup automatic starters in power grids and do not require redesign and production.

[0036] 4. The simplified operation mode of the backup automatic switching device of the single busbar sectionalized connection substation with four power supplies is verified by logical algebra, which is clear and easy to understand. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is an example diagram of the primary main connection of a single busbar sectionalized wiring substation powered by four power supplies to which the simplified method of the present invention is applied;

[0038] Figure 2 The simplified method of the present invention is applied to the primary main wiring diagram of the high voltage side of a single busbar segmented wiring substation powered by four power supplies. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0040] like Figure 1 As shown, in a single-bus sectionalized connection substation powered by four power supplies to which the method of the present invention is applied, taking three 110kV substations in chain connection as an example, substation 1, substation 2, and substation 3 all involve four power supplies, and the four power supplies of substation 1 are S1, S2, S3, and S4 respectively. Power sources S1 and S2 supply power to 110kV substation 1 through line 1 and line 2 respectively, and power source S1 supplies power to section I bus of substation 1 through line 1 via circuit breaker QF1, and power source S2 supplies power to section II bus of substation 1 through line 2 via circuit breaker QF2. The 110kV side of substation 1 is in the form of "hand in hand", with section I bus connected to 110kV substation 2 through tie line line 4 via circuit breaker QF4, and section II bus connected to 110kV substation 2 through tie line line 5 via circuit breaker QF5. Line 4 is connected to 110kV section I bus of substation 2 through circuit breaker QF6, and line 5 is connected to 110kV section II bus of substation 2 through circuit breaker QF7. Similarly, the busbar section I of the 110kV side of substation 2 is connected to the 110kV substation 3 through the tie line line 6 via the circuit breaker QF9, and the busbar section II is connected to the 110kV substation 3 through the tie line line 7 via the circuit breaker QF10. Line 6 is connected to the 110kV busbar section I of substation 3 through the circuit breaker QF11, and line 7 is connected to the 110kV busbar section II of substation 3 through the circuit breaker QF12. Power sources S3 and S4 supply power to the busbar sections I and II of substation 3 through line 8 through the circuit breaker QF14 and line 9 through the circuit breaker QF15, respectively.

[0041] The 110kV side wiring mode of 110kV substation 1, substation 2 and substation 3 all adopt single busbar segmented wiring, and the segmented circuit breakers are QF3, QF8 and QF13 respectively. Take 110kV substation 1 as an example (see Figure 2 ), in addition to the line branches, the bus section I of substation 1 is connected with main transformer No. 1 and bus voltage transformer TV1, and the bus section II is connected with main transformer No. 2 and bus voltage transformer TV2.

[0042] The simplified process of the present invention is specifically implemented as follows:

[0043] 1 Simplification of automatic switching of single busbar sectionalized substation with four power supplies

[0044] 1.1 Operation mode of single busbar sectionalized substation with four power supplies

[0045] The single busbar sectionalized substation with four power supplies adopts multiple power supplies. Each busbar section has two interconnecting lines with one input and one output. Figure 1 , Figure 2 . Two power sources cannot be operated in parallel for a long time, and at least one circuit breaker in the loop between two power sources should be in hot standby mode. According to the "exhaustive method", 27 operation modes can be listed for the automatic switching of the single busbar sectionalized connection substation with four power sources, as shown in Table 1.

[0046] Table 1. Possible operation modes of automatic switching in a single busbar sectionalized substation with four power supplies

[0047]

[0048]

[0049]

[0050] 1.2 Simplification of automatic switching of single busbar sectionalized substation with four power supplies

[0051] 1.2.1 Primary main connection of single busbar sectionalized substation with four power supplies

[0052] Figure 2 It is the primary main connection of a single-busbar sectionalized connection substation powered by four power sources. The high-voltage side of the substation is a single-busbar sectionalized connection: the high-voltage section I bus is connected with circuit breakers QF1, QF3, and QF4, and the high-voltage section II bus is connected with circuit breakers QF2, QF3, and QF5, among which circuit breaker QF3 is a sectionalized circuit breaker.

[0053] 1.2.2 Simplification of automatic switching of single busbar sectionalized substation with four power supplies

[0054] If the standby automatic switch is considered for the entire substation, there are as many as 27 operating modes, which are not easy to remember and complicated to operate. For simple processing, the standby automatic switch of the single busbar sectionalized wiring substation with four power supplies can be composed of 4 single busbar sectionalized wiring standby automatic switches and 2 single busbar standby automatic switches:

[0055] a. Single-mother sectionalized wiring standby automatic switching (abbreviated as standby automatic switching 1) consisting of circuit breakers QF1, QF2 and QF3;

[0056] b. Single-mother sectionalized wiring standby automatic switching (abbreviated as standby automatic switching 2) composed of circuit breakers QF3, QF4 and QF5;

[0057] c. Single-mother sectionalized wiring standby automatic switching (abbreviated as standby automatic switching 3) consisting of circuit breakers QF1, QF3 and QF5;

[0058] d. Single-mother sectionalized wiring standby automatic switching (abbreviated as standby automatic switching 4) composed of circuit breakers QF2, QF3 and QF4;

[0059] e. Single busbar standby automatic switching (abbreviated as standby automatic switching 5) composed of circuit breakers QF1 and QF4;

[0060] f. Single busbar standby automatic switching circuit composed of circuit breakers QF2 and QF5 (abbreviated as standby automatic switching circuit 6).

[0061] The possible operating modes of the simplified single-busbar sectionalized substation with four power supplies can be listed into 27 operating modes by "exhaustive enumeration method", as shown in Table 2.

[0062] Table 2. Possible operation modes of the simplified four-power-supply single-busbar sectionalized substation backup automatic switching

[0063]

[0064]

[0065]

[0066] 2. Verification of the correctness of the simplified operation mode of the single busbar sectionalized connection substation with four power supplies

[0067] 2.1 Mathematical model of automatic backup

[0068] Can the backup automatic starter of a single-busbar sectionalized connection substation with four power supplies be simplified to a combination of four single-busbar sectionalized connection backup automatic starters and two single-busbar connection backup automatic starters? The logic algebra method is used to verify the applicable operating modes of the six backup automatic starters, which can meet all the operating mode requirements of the single-busbar sectionalized connection substation with four power supplies. The backup automatic starter of its fixed wiring mode can be realized by several of the six backup automatic starters. The closed and non-closed states of the circuit breaker can be represented by logic algebra, with 1 in logic algebra indicating that the circuit breaker is in the closed state, and 0 in logic algebra indicating that the circuit breaker is in the non-closed state (satisfying the premise of a reasonable operating mode). A, B, C, D, and E are used to indicate that the circuit breakers QF1, QF2, QF3, QF4, and QF5 are in the closed state, which are respectively represented by 1 in logic algebra; They respectively indicate that the circuit breakers QF1, QF2, QF3, QF4, and QF5 are in the non-closed state, and are represented by 0 in logical algebra.

[0069] 2.1.1 Mathematical model of automatic backup 1

[0070] Figure 2 The operation and non-operation of QF1, QF2, and QF3 in the primary main connection of the single busbar sectionalized connection constitutes 6 operation modes of the single busbar sectionalized connection standby automatic switching:

[0071] a. Circuit breakers QF1 and QF2 are in operation, and circuit breaker QF3 is in standby mode. When incoming line 1 loses power, circuit breaker QF1 is tripped and circuit breaker QF3 is switched on; when incoming line 2 loses power, circuit breaker QF2 is tripped and circuit breaker QF3 is switched on. The logical algebraic expression of its operation mode is:

[0072] b. Circuit breakers QF1 and QF3 are in operation, and circuit breaker QF2 is in standby mode. When incoming line 1 loses power, circuit breaker QF1 is tripped and circuit breaker QF2 is switched on. The logical algebraic expression of its operation mode is:

[0073] c. Circuit breakers QF2 and QF3 are in operation, and circuit breaker QF1 is in standby operation. When incoming line 2 loses power, circuit breaker QF2 is tripped and circuit breaker QF1 is switched on. The logical algebraic expression of its operation mode is:

[0074] d. Circuit breaker QF1 is running, and circuit breakers QF2 and QF3 are in standby mode. When incoming line 1 loses power, circuit breaker QF1 is tripped, and circuit breakers QF2 and QF3 are switched on. The logical algebraic expression of its operation mode is:

[0075] e. Circuit breaker QF2 is running, and circuit breakers QF1 and QF3 are in standby mode. When incoming line 2 loses power, circuit breaker QF2 is tripped, and circuit breakers QF1 and QF3 are in operation. The logical algebraic expression of its operation mode is:

[0076] The logical algebraic expression satisfied by the automatic start-up mode 1 is obtained as follows:

[0077]

[0078] 2.1.2 Mathematical model of automatic backup 2

[0079] Figure 2 The operation and non-operation of QF3, QF4, and QF5 in the primary main connection of the single busbar sectionalized connection constitutes 6 operation modes of the single busbar sectionalized connection standby automatic switching:

[0080] a. Circuit breakers QF4 and QF5 are in operation, and circuit breaker QF3 is in standby mode. When incoming line 4 loses power, circuit breaker QF4 is tripped and circuit breaker QF3 is switched on; when incoming line 5 loses power, circuit breaker QF5 is tripped and circuit breaker QF3 is switched on. The logical algebraic expression of its operation mode is:

[0081] b. Circuit breakers QF3 and QF4 are in operation, and circuit breaker QF5 is in standby mode. When incoming line 4 loses power, circuit breaker QF4 is tripped and circuit breaker QF5 is switched on. The logical algebraic expression of its operation mode is:

[0082] c. Circuit breakers QF3 and QF5 are in operation, and circuit breaker QF4 is in standby mode. When incoming line 5 loses power, circuit breaker QF5 is tripped and circuit breaker QF4 is switched on. The logical algebraic expression of its operation mode is:

[0083] d. Circuit breaker QF4 is running, and circuit breakers QF3 and QF5 are in standby mode. When incoming line 3 loses power, circuit breaker QF4 is tripped, and circuit breakers QF3 and QF5 are switched on. The logical algebraic expression of its operation mode is:

[0084] e. Circuit breaker QF5 is running, and circuit breakers QF3 and QF4 are in standby mode. When incoming line 4 loses power, circuit breaker QF5 is tripped, and circuit breakers QF3 and QF4 are in operation. The logical algebraic expression of its operation mode is:

[0085] The logical algebraic expression satisfied by the automatic start-up mode 2 is obtained as follows:

[0086]

[0087] 2.1.3 Mathematical model of automatic backup 3

[0088] Figure 2 The operation and non-operation of QF1, QF3, and QF5 in the primary main connection of the single busbar sectionalized connection constitutes 6 operation modes of the single busbar sectionalized connection standby automatic switching:

[0089] a. Circuit breakers QF1 and QF5 are in operation, and circuit breaker QF3 is in standby mode. When incoming line 1 loses power, circuit breaker QF1 is tripped and circuit breaker QF3 is switched on; when incoming line 4 loses power, circuit breaker QF5 is tripped and circuit breaker QF3 is switched on. The logical algebraic expression of its operation mode is:

[0090] b. Circuit breakers QF1 and QF3 are in operation, and circuit breaker QF5 is in standby mode. When incoming line 1 loses power, circuit breaker QF1 is tripped and circuit breaker QF5 is switched on. The logical algebraic expression of its operation mode is:

[0091] c. Circuit breakers QF3 and QF5 are in operation, and circuit breaker QF1 is in standby mode. When incoming line 4 loses power, circuit breaker QF5 is tripped and circuit breaker QF1 is switched on. The logical algebraic expression of its operation mode is:

[0092] d. Circuit breaker QF1 is running, and circuit breakers QF3 and QF5 are in standby mode. When incoming line 1 loses power, circuit breaker QF1 is tripped, and circuit breakers QF3 and QF5 are switched on. The logical algebraic expression of its operation mode is:

[0093] e. Circuit breaker QF5 is running, and circuit breakers QF1 and QF3 are in standby mode. When incoming line 4 loses power, circuit breaker QF5 is tripped, and circuit breakers QF1 and QF3 are in operation. The logical algebraic expression of its operation mode is:

[0094] The logical algebraic expression satisfied by the automatic start-up mode 3 is obtained as follows:

[0095]

[0096] 2.1.4 Mathematical model of automatic backup 4

[0097] Figure 2 The operation and non-operation of QF2, QF3, and QF4 in the primary main connection of the single busbar sectionalized connection constitutes 6 operation modes of the single busbar sectionalized connection standby automatic switching:

[0098] a. Circuit breakers QF2 and QF4 are in operation, and circuit breaker QF3 is in standby mode. When incoming line 2 loses power, circuit breaker QF2 is tripped and circuit breaker QF3 is switched on. ；When the power supply of incoming line 3 is lost, the QF4 circuit breaker is tripped and the QF3 circuit breaker is put on. The logical algebraic expression of its operation mode is:

[0099] b. Circuit breakers QF2 and QF3 are in operation, and circuit breaker QF4 is in standby mode. When incoming line 2 loses power, circuit breaker QF2 is tripped and circuit breaker QF4 is switched on. The logical algebraic expression of its operation mode is:

[0100] c. Circuit breakers QF3 and QF4 are in operation, and circuit breaker QF2 is in standby mode. When incoming line 3 loses power, circuit breaker QF4 is tripped and circuit breaker QF2 is switched on. The logical algebraic expression of its operation mode is:

[0101] d. Circuit breaker QF2 is running, and circuit breakers QF3 and QF4 are in standby mode. When incoming line 2 loses power, circuit breaker QF2 is tripped, and circuit breakers QF3 and QF4 are switched on. The logical algebraic expression of its operation mode is:

[0102] e. Circuit breaker QF4 is running, and circuit breakers QF2 and QF3 are in standby mode. When incoming line 3 loses power, circuit breaker QF4 is tripped, and circuit breakers QF2 and QF3 are switched on. The logical algebraic expression of its operation mode is:

[0103] The logical algebraic expression satisfied by the automatic start-up mode 4 is obtained as follows:

[0104]

[0105] 2.1.5 Mathematical model of automatic backup 5

[0106] Figure 2 The operation and non-operation of QF1 and QF4 in the primary main connection of the single busbar segmented connection constitute three operation modes of the single busbar standby automatic switching:

[0107] a. Circuit breaker QF1 is running, and circuit breaker QF4 is in standby mode. When incoming line 1 loses power, circuit breaker QF1 is tripped and circuit breaker QF4 is switched on. The logical algebraic expression of its operation mode is:

[0108] b. Circuit breaker QF4 is running, and circuit breaker QF1 is in standby mode. When the incoming line 3 loses power, circuit breaker QF4 is tripped and circuit breaker QF1 is switched on. The logical algebraic expression of its operation mode is:

[0109] The logical algebraic expression satisfied by the automatic transfer mode 5 is (5):

[0110]

[0111] 2.1.6 Mathematical model of automatic backup 6

[0112] Figure 2 The operation and non-operation of QF2 and QF5 in the primary main connection of the single busbar segmented connection constitute three operation modes of the single busbar standby automatic switching:

[0113] a. Circuit breaker QF2 is running, and circuit breaker QF5 is in standby mode. When incoming line 2 loses power, circuit breaker QF2 is tripped and circuit breaker QF5 is switched on. The logical algebraic expression of its operation mode is:

[0114] b. Circuit breaker QF5 is running, and circuit breaker QF2 is in standby mode. When incoming line 4 loses power, circuit breaker QF5 is tripped and circuit breaker QF2 is switched on. The logical algebraic expression of its operation mode is:

[0115] The logical algebraic expression satisfied by the automatic start-up mode 6 is (6):

[0116]

[0117] 2.2 Theoretical Analysis of Automatic Switching of Single Bus Sectional Substation with Four Power Sources

[0118] The logical relationship between the backup automatic start-up 1 and other circuit breakers QF4 and QF5 is equivalent to the "and" logical relationship, and the logical algebraic expression of the operation mode of the backup automatic start-up 1 is obtained as follows:

[0119]

[0120] By operating formula (7), we can get

[0121]

[0122] The logical relationship between the backup automatic start-up 2 and other circuit breakers QF1 and QF2 is equivalent to the "and" logical relationship, and the logical algebraic expression of the operation mode of the backup automatic start-up 2 is obtained as follows:

[0123]

[0124] By operating formula (9), we can get

[0125]

[0126] The logical relationship between the backup automatic start-up 3 and other circuit breakers QF2 and QF4 is equivalent to the "and" logical relationship, and the logical algebraic expression of the operation mode of the backup automatic start-up 3 is obtained as follows:

[0127]

[0128] By operating formula (11), we can get

[0129]

[0130] The logical relationship between the backup automatic start-up 4 and other circuit breakers QF1 and QF5 is equivalent to the "and" logical relationship, and the logical algebraic expression of the backup automatic start-up 4 operation mode is obtained as follows:

[0131]

[0132] By operating formula (13), we can get

[0133]

[0134] The logical relationship between the backup automatic switch 5 and other circuit breakers QF2, QF3, QF5 is equivalent to the "and" logical relationship, and the logical algebraic expression of the operation mode of the backup automatic switch 5 is obtained as follows:

[0135]

[0136] By operating formula (15), we can get

[0137]

[0138] The logical relationship between the backup automatic starter 6 and other circuit breakers QF1, QF3, QF4 is equivalent to the "and" logical relationship, and the logical algebraic expression of the backup automatic starter 6 operation mode is obtained as follows:

[0139]

[0140] By operating formula (17), we can get

[0141]

[0142] Arrange (8), (10), (12), (14), (16), (18), merge the duplicates, and consider The operation mode does not exist, ABCDE, If there is no backup automatic start-up mode, equations (8), (10), (12), (14), (16), and (18) become equation (19):

[0143]

[0144] In formula (19), there are 27 operating modes in total.

[0145] 2.3 Comparison of operation modes: The logical algebraic expression of each field in formula (19) represents an operation mode of a single-busbar sectionalized connection substation with four power supplies, which is consistent with the "exhaustive" operation mode of a single-busbar sectionalized connection substation with four power supplies. That is, the simplified operation mode of the single-busbar sectionalized connection substation with four power supplies and the listed operation mode of the single-busbar sectionalized connection substation with four power supplies and the "exhaustive method" is the same, indicating that the operation effect is the same.

[0146] Through the above steps, it is verified that the simplified automatic switching operation of the single-busbar sectionalized connection substation with four power supplies is the same as that of the single-busbar sectionalized connection substation with four power supplies by the "exhaustive method".

Claims

1. A method for simplifying the backup automatic switching logic of a single busbar sectionalized connection substation with four power supplies, characterized in that: The single busbar sectionalized connection substation with four power supplies is simplified to consist of four single busbar sectionalized connection substations and two single busbar connection substations. The circuit breakers QF1, QF2 and QF3 of the single busbar sectionalized wiring substation line powered by four power supplies form a single busbar sectionalized wiring standby automatic switch of three circuit breakers of dual power supplies, referred to as standby automatic switch 1; The single mother section wiring standby automatic transfer of the dual power supply three circuit breakers composed of circuit breakers QF3, QF4 and QF5 is referred to as standby automatic transfer 2; The single mother section wiring standby automatic switching of the dual power supply three circuit breakers composed of circuit breakers QF1, QF3 and QF5 is referred to as standby automatic switching 3; The single mother section wiring standby automatic switching of the dual power supply three circuit breakers composed of circuit breakers QF2, QF3 and QF4 is referred to as standby automatic switching 4; The single busbar standby automatic transfer of two circuit breakers of dual power supply composed of circuit breakers QF1 and QF4 is referred to as standby automatic transfer 5; The single busbar standby automatic transfer of two circuit breakers of dual power supply composed of circuit breakers QF2 and QF5 is referred to as standby automatic transfer 6; The operation mode of the standby automatic input 1 satisfies the following logical algebraic expression: The operation mode of the standby automatic input 2 satisfies the following logical algebraic expression: The operation mode of the standby automatic input 3 satisfies the following logical algebraic expression: The operation mode of the standby automatic input 4 satisfies the following logical algebraic expression: The operation mode of the standby automatic input 5 satisfies the following logical algebraic expression: The operation mode of the standby automatic input 6 satisfies the following logical algebraic expression: The logical relationship between the above backup and automatic switching is "OR". The logical algebraic expression of the backup and automatic switching of the single busbar sectionalized substation with four power supplies is: Among them, A, B, C, D, and E respectively represent that the circuit breakers QF1, QF2, QF3, QF4, and QF5 are in the closed operating state, and are respectively represented by 1 in logical algebra; Respectively indicate that the circuit breakers QF1, QF2, QF3, QF4, and QF5 are in the open operation state, that is, the hot standby state, and are respectively represented by 0 in logical algebra; The logical algebraic expression of each field in the above formula represents an operating mode of a single-bus sectionalized substation powered by four power sources, with a total of 27 operating modes.

2. The method for simplifying the backup automatic switching logic of a single busbar sectionalized connection substation with four power supplies as claimed in claim 1, characterized in that: The control logic of the standby automatic transfer of the single-busbar sectionalized connection substation powered by four power sources consists of six parts, namely, the single-busbar sectionalized connection standby automatic transfer logic composed of the high-voltage side circuit breakers QF1, QF2, and QF3, the single-busbar sectionalized connection standby automatic transfer logic composed of the circuit breakers QF3, QF4, and QF5, the single-busbar sectionalized connection standby automatic transfer logic composed of the circuit breakers QF2, QF3, and QF4, the single-busbar sectionalized connection standby automatic transfer logic composed of the circuit breakers QF1, QF3, and QF5, the single-busbar sectionalized connection standby automatic transfer logic composed of the circuit breakers QF1 and QF4, and the single-busbar sectionalized connection standby automatic transfer logic composed of the circuit breakers QF2 and QF5. These six parts are arranged in the same standby automatic transfer device.

3. The method for simplifying the backup automatic switching logic of a single busbar sectionalized connection substation with four power supplies as claimed in claim 2, characterized in that: When more than one of the six standby automatic switching devices meets the action conditions, selection is achieved by setting the action delay between the six standby automatic switching devices.

4. The method for simplifying the backup automatic switching logic of a single busbar sectionalized connection substation with four power supplies as claimed in claim 2, characterized in that: When more than one of the six backup automatic switching devices meets the action conditions, selection is achieved by adding judgment logic between the backup automatic switching devices.

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