Calculation method for acceleration action after three-section spare power automatic switching
By dynamically calculating the overcurrent time limit and tripping overcurrent threshold of the circuit breaker, the circuit breaker is quickly jumped out, solving the problem of aggravating the fault hazards in permanent failures, and achieving rapid failure in the event of a fault The process enhances power supply safety.
Patent Information
- Application Number
- CN202411269153.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2024-12-13
AI Technical Summary
In the case of permanent failure, the existing three-stage self-investment investment aggravates the damage to the fault and lacks a method to quickly jump the circuit breaker, resulting in the amplification of the accident.
A three-stage self-initiated acceleration operation calculation method is adopted, and the overcurrent time limit and tripping overcurrent threshold of the circuit breaker are dynamically calculated, and the tripping command is issued during the self-initiated closing opening period according to the current fault current. Quickly jump to the circuit breaker.
Accelerate the circuit breaker to reduce the fault time and enhance the safe use range of self-operated supply.
Smart Images
Figure CN119134625A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to electric power system technology, in particular to a calculation method for a three-stage automatic standby after-throw acceleration action technology. Background Art
[0002] At present, the requirements for power supply reliability are getting higher and higher. Installing a standby incoming line automatic input device on a multi-power supply line can improve the power supply reliability. The standby incoming line automatic input device is usually referred to as a standby automatic input device.
[0003] The busbar for the low-voltage 400V power supply of a hydropower plant usually uses a three-section busbar. Under normal circumstances, the two working busbars are both energized and powered by two incoming lines. The third busbar is a backup busbar, which is not energized. Under abnormal circumstances, it is powered by the backup third power supply.
[0004] The three-way power supply brings complexity to the power supply mode. The normal power supply mode will add multiple combinations, and the abnormal mode will also become complicated. The requirements for the dispatching personnel's switching operations are higher. The slightest error will form a ring network operation, leading to accidents or the expansion of accidents.
[0005] The three power sources are connected to the three busbars separately, forming a power supply mode that can be divided. Under different power supply conditions, the problem to be solved by the three power supply load is to quickly switch to form a safe and reliable operation mode. However, in the case of permanent fault, the input of the backup automatic switch will aggravate the harm of the fault and even expand the scope of the fault.
[0006] When a three-stage backup automatic switch is put into operation in the event of a permanent fault, the circuit breaker needs to be tripped quickly to reduce the harm of the accident. Currently, a fixed time and fixed threshold mode is used, and there is a lack of a faster tripping method. Summary of the invention
[0007] In view of the defects existing in the above-mentioned prior art, the technical problem to be solved by the present invention is to provide a calculation method for the three-stage standby automatic post-closing acceleration action which can accelerate the tripping of the circuit breaker according to the current fault current in the case of a fault.
[0008] In order to solve the above technical problems, the present invention provides a calculation method for the acceleration action after the three-stage standby automatic switching, wherein the three-stage power supply line includes three segmented power supply busbars, the three segmented power supply busbars are busbar 1#, busbar 2#, and busbar 3#, wherein busbar 3# is a standby busbar, busbar 1# is connected in series with a segmented circuit breaker 11DK, busbar 2# is connected in series with a segmented circuit breaker 12DK, busbar 3# is connected in series with a segmented circuit breaker 13DK, busbar 1# is connected to busbar 3# through a connecting circuit breaker 431DK, and busbar 2# is connected to busbar 3# through a connecting circuit breaker 432DK; it is characterized in that the specific steps are as follows:
[0009] 1) Define the current time as time t;
[0010] 2) If the backup automatic switch does not work at time t, wait for time α and set t=t+α, then repeat this step. Otherwise, go to step 3), where α is the preset time threshold;
[0011] 3) Set the standby automatic switching action time t0=t, the standby automatic switching initial closing time ct1=0, and the standby automatic switching current closing time ct2=0;
[0012] 4) If the closing action of the section circuit breaker or the connecting circuit breaker occurs, the circuit breaker with the closing action is set as the circuit breaker closeBK, and the initial closing time of the standby automatic switching ct1=t, and then go to step 5);
[0013] Otherwise, wait for α time and set t=t+α, then judge the value of t. If t-t0≧Tbact, go to step 2). Otherwise, repeat this step. Tbact is the preset time limit of standby automatic operation.
[0014] 5) Calculate the dynamic overcurrent time limit of section circuit breaker 11DK, section circuit breaker 12DK, tie circuit breaker 431DK, and tie circuit breaker 432DK at the current time. The specific calculation formula is:
[0015]
[0016] Wherein, f(t1) is the dynamic overcurrent time limit of the section circuit breaker 11DK at time t, f(t2) is the dynamic overcurrent time limit of the section circuit breaker 12DK at time t, f(t3) is the dynamic overcurrent time limit of the tie circuit breaker 431DK at time t, f(t4) is the dynamic overcurrent time limit of the tie circuit breaker 432DK at time t, I1 is the current of the section circuit breaker 11DK at time t, I2 is the current of the section circuit breaker 12DK at time t, I3 is the current of the tie circuit breaker 431DK at time t, I4 is the current of the tie circuit breaker 432DK at time t, Tlimit is the preset overcurrent time threshold of each section circuit breaker and each tie circuit breaker, and Ilimit is the preset tripping overcurrent threshold of each section circuit breaker and each tie circuit breaker;
[0017] If any one of f(t1), f(t2), f(t3), f(t4) is less than Tlimit, go to step 6);
[0018] Otherwise, wait for α time and set t=t+α, set ct1=t, and then judge the value of t. If t-t0≧Tbact, go to step 2), otherwise repeat this step;
[0019] 6) Let the current closing time of the backup power supply automatic switching device ct2 == t, and after waiting for α time, let t = t + α;
[0020] 7) If ct2 - ct1 is greater than any one of f(t1), f(t2), f(t3), f(t4), and t - ct1 < Topen, then issue a tripping command for the circuit breaker closeBK, and then go to step 2); Topen is the preset closing opening time period of the backup power supply automatic switching device;
[0021] If ct2 - ct1 is less than or equal to any one of f(t1), f(t2), f(t3), f(t4), and t - ct1 < Topen, then go to step 5);
[0022] If t - ct1 ≧ Topen, then go to step 2).
[0023] The calculation method for the post-acceleration operation of the three-stage backup power supply automatic switching device provided by the present invention continuously corrects the dynamic overcurrent time limit value of the relevant circuit breaker according to the current of the circuit breaker at the current time, the overcurrent time threshold value, and the tripping overcurrent threshold value. When the overcurrent time within the closing opening time period of the backup power supply automatic switching device accumulates to the dynamic overcurrent time limit value, a tripping command for the tie circuit breaker is issued, so that the circuit breaker can be quickly tripped according to the current fault current in case of a fault, reducing the fault time and enhancing the safe use range of the backup power supply automatic switching device. Description of the Drawings
[0024] Figure 1 It is a schematic diagram of the line structure of the three-stage power supply line in the calculation method for the post-acceleration operation of the three-stage backup power supply automatic switching device according to the embodiment of the present invention. Detailed Embodiment
[0025] The following further describes in detail the embodiments of the present invention in conjunction with the description of the drawings, but the present embodiments do not limit the present invention. Any similar structure and its similar changes adopted in the present invention shall be included in the protection scope of the present invention. The commas in the present invention all represent the relationship of "and". The English letters in the present invention are case-sensitive.
[0026] As Figure 1 shown, a calculation method for the post-acceleration operation of a three-stage backup power supply automatic switching device provided by an embodiment of the present invention. The three-stage power supply line includes three sectional power supply buses, which are respectively bus 1#, bus 2#, and bus 3#. Among them, bus 3# is the standby bus. A sectional circuit breaker 11DK is connected in series on bus 1#, a sectional circuit breaker 12DK is connected in series on bus 2#, a sectional circuit breaker 13DK is connected in series on bus 3#, bus 1# is connected to bus 3# through a tie circuit breaker 431DK, and bus 2# is connected to bus 3# through a tie circuit breaker 432DK; characterized in that the specific steps are as follows:
[0027] 1) Define the current time as time t;
[0028] 2) If the backup automatic switch does not work at time t, wait for time α and set t=t+α, then repeat this step. Otherwise, go to step 3), where α is the preset time threshold, and the typical value of α is 5ms;
[0029] 3) Set the standby automatic switching action time t0=t, the standby automatic switching initial closing time ct1=0, and the standby automatic switching current closing time ct2=0;
[0030] 4) If the closing action of the section circuit breaker or the connecting circuit breaker occurs, the circuit breaker with the closing action is set as the circuit breaker closeBK, and the initial closing time of the standby automatic switching ct1=t, and then go to step 5);
[0031] Otherwise, wait for α time and set t=t+α, then judge the value of t. If t-t0≧Tbact, go to step 2). Otherwise, repeat this step. Tbact is the preset time limit of the standby automatic operation. The typical value of Tbact is 400ms.
[0032] 5) Calculate the dynamic overcurrent time limit of section circuit breaker 11DK, section circuit breaker 12DK, tie circuit breaker 431DK, and tie circuit breaker 432DK at the current time. The specific calculation formula is:
[0033]
[0034] Wherein, f(t1) is the dynamic overcurrent time limit of the section circuit breaker 11DK at time t, f(t2) is the dynamic overcurrent time limit of the section circuit breaker 12DK at time t, f(t3) is the dynamic overcurrent time limit of the tie circuit breaker 431DK at time t, f(t4) is the dynamic overcurrent time limit of the tie circuit breaker 432DK at time t, I1 is the current of the section circuit breaker 11DK at time t, I2 is the current of the section circuit breaker 12DK at time t, I3 is the current of the tie circuit breaker 431DK at time t, I4 is the current of the tie circuit breaker 432DK at time t, Tlimit is the preset overcurrent time threshold of each section circuit breaker and each tie circuit breaker, and Ilimit is the preset tripping overcurrent threshold of each section circuit breaker and each tie circuit breaker;
[0035] If any one of f(t1), f(t2), f(t3), f(t4) is less than Tlimit, go to step 6);
[0036] Otherwise, wait for α time and set t=t+α, set ct1=t, and then judge the value of t. If t-t0≧Tbact, go to step 2), otherwise repeat this step;
[0037] 6) Set the current closing time ct2 of the backup power supply automatic switching device to be equal to t, and after waiting for α time, set t = t + α;
[0038] 7) If ct2 - ct1 is greater than any one of f(t1), f(t2), f(t3), f(t4), and t - ct1 < Topen, then issue a tripping command for the circuit breaker closeBK, and then go to step 2); Topen is the preset backup power supply automatic switching closing open time period. When the backup power supply automatic switching device operates, it is judged whether there is an overcurrent phenomenon within the backup power supply automatic switching closing open time period. The typical value of Topen is [5ms, 400ms], and Topen < Tbact;
[0039] If ct2 - ct1 is less than or equal to any one of f(t1), f(t2), f(t3), f(t4), and t - ct1 < Topen, then go to step 5);
[0040] If t - ct1 ≥ Topen, then go to step 2).
Claims
1. A calculation method for the acceleration action after a three-stage standby automatic switching, wherein the three-stage power supply line includes three segmented power supply buses, the three segmented power supply buses are bus 1#, bus 2#, and bus 3#, wherein bus 3# is a standby bus, bus 1# is connected in series with a segmented circuit breaker 11DK, bus 2# is connected in series with a segmented circuit breaker 12DK, bus 3# is connected in series with a segmented circuit breaker 13DK, bus 1# is connected to bus 3# via a connecting circuit breaker 431DK, and bus 2# is connected to bus 3# via a connecting circuit breaker 432DK; It is characterized in that The specific steps are as follows: 1) Define the current time as time t; 2) If the backup automatic switch does not work at time t, wait for time α and set t=t+α, then repeat this step. Otherwise, go to step 3), where α is the preset time threshold; 3) Set the standby automatic switching action time t0=t, the standby automatic switching initial closing time ct1=0, and the standby automatic switching current closing time ct2=0; 4) If the closing action of the section circuit breaker or the connecting circuit breaker occurs, the circuit breaker with the closing action is set as the circuit breaker closeBK, and the initial closing time of the standby automatic switching ct1=t, and then go to step 5); Otherwise, wait for α time and set t=t+α, then judge the value of t. If t-t0≧Tbact, go to step 2). Otherwise, repeat this step. Tbact is the preset time limit of standby automatic operation. 5) Calculate the dynamic overcurrent time limit of section circuit breaker 11DK, section circuit breaker 12DK, tie circuit breaker 431DK, and tie circuit breaker 432DK at the current time. The specific calculation formula is: In the formula, f(t 1 ) is the dynamic overcurrent time limit of the section circuit breaker 11DK at time t, f(t 2 ) is the dynamic overcurrent time limit of the section circuit breaker 12DK at time t, f(t 3 ) is the dynamic overcurrent time limit of the tie circuit breaker 431DK at time t, f(t 4 ) is the dynamic overcurrent time limit of the tie circuit breaker 432DK at time t, I 1 is the current of the section circuit breaker 11DK at time t, I 2 is the current of the section circuit breaker 12DK at time t, I 3 is the current of the contact circuit breaker 431DK at time t, I 4 is the current of the interconnecting circuit breaker 432DK at time t, Tlimit is the preset overcurrent time threshold of each section circuit breaker and each interconnecting circuit breaker, and Ilimit is the preset tripping overcurrent threshold of each section circuit breaker and each interconnecting circuit breaker; If f(t 1 )、f(t 2 )、f(t 3 )、f(t 4 ) is less than Tlimit, go to step 6); Otherwise, wait for α time and set t=t+α, set ct1=t, and then judge the value of t. If t-t0≧Tbact, go to step 2), otherwise repeat this step; 6) Set the current closing time of the standby automatic switch ct2 to t, and wait for α time and set t to t+α; 7) If ct2 - ct1 is greater than any one of f(t 1 ), f(t 2 ), f(t 3 ), f(t 4 ), and t - ct1 < Topen, then issue a trip command for the circuit breaker closeBK and then go to step 2); Topen is a preset open period for the automatic bus transfer closing; If ct2 - ct1 is less than or equal to any one of f(t 1 ), f(t 2 ), f(t 3 ), f(t 4 ), and t - ct1 < Topen, then go to step 5); If t-ct1≧Topen, go to step 2).