Low-voltage release protection setting method and device, electronic equipment and storage medium

Abstract

The application discloses a low-voltage release protection setting method, and at least comprises the following steps: numbering motors according to starting priority; calculating the minimum short-circuit capacity S of a low-voltage bus connected with a low-voltage release min ; setting the maximum allowed drop value U of the voltage of the low-voltage bus during motor starting sag ; comparing β1S1+β2S2+…β n S n ; and setting the setting voltage and action delay of the low-voltage release corresponding to the motor according to the comparison result. The application further discloses a low-voltage release protection setting device, electronic equipment and a non-transient computer readable storage medium. The application can effectively avoid group starting failure caused by the voltage drop of the bus during low-voltage motor group starting, and preferentially guarantees that important motors do not release.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power quality optimization, in particular to the technical field of voltage sag management in low-voltage power grid, and particularly relates to a low-voltage release protection setting method and device, an electronic device and a storage medium. BACKGROUND

[0002] As a core accessory of a circuit breaker, a low-voltage release controls the operating mechanism of the circuit breaker to realize protection functions such as overload, short circuit and undervoltage. Undervoltage release is widely used in current low-voltage releases. GB 14048.1-2006 Low-voltage switchgear and controlgear - Part 1: common requirements specifies the action range and time of the undervoltage release device in the low-voltage power grid. When the line voltage is 85% to 110% of the rated voltage, the undervoltage release can be reliably attracted. The action range of the undervoltage release is specified to be 35% to 70% of the rated voltage, and the zero-voltage (loss of voltage) release action voltage is 10% to 35% of the rated voltage.

[0003] Voltage sag has been recognized as one of the most important power quality problems, which seriously affects the safety and normal operation of electrical equipment. Voltage sag refers to a short-time voltage variation phenomenon in which the effective value of the supply voltage suddenly drops to 90% to 10% of the rated value within a short time and then rises to the vicinity of the normal value, with a duration of 0.5 cycles to 1 minute.

[0004] In order to improve power quality, more and more attention has been paid to the management of voltage sag. Some studies have found that using a reasonable setting method of low-voltage release can reduce the impact of voltage sag to a certain extent. For example, the normal voltage fluctuation of the power grid can be avoided by using the undervoltage release delay setting method. However, the existing low-voltage release protection setting method does not take into account the situation that the voltage of the low-voltage bus is too low when all motor groups on the low-voltage bus are started or accelerated to the rated speed during voltage recovery. This situation of motor group restart causing low bus voltage may cause problems such as low-voltage burnout of some motors and failure of motor group restart.

[0005] The information disclosed in this BACKGROUND section is only intended to increase an understanding of the general context of the application and should not be taken as an acknowledgement or any form of suggestion that this information constitutes prior art. SUMMARY

[0006] One of the purposes of the present application is to provide a low-voltage release protection setting method and device, an electronic device and a storage medium, thereby optimizing power quality.

[0007] Another objective of this invention is to provide a low-voltage trip unit protection setting method, device, electronic equipment, and storage medium to ensure the safety and effectiveness of motor group startup or restart.

[0008] To achieve the above objectives, according to a first aspect of the present invention, the present invention provides a low-voltage trip unit protection setting method, comprising at least the following steps:

[0009] The motors are numbered 1, 2...n according to their starting priority, and their capacities are S1, S2...S... n The starting current multiples are β1, β2...β n ;

[0010] Calculate the minimum short-circuit capacity S of the low-voltage busbar connected to the low-voltage trip unit. min ;

[0011] Set the maximum allowable voltage drop U of the low-voltage bus during motor startup. sag ;

[0012] Compare β1S1+β2S2+…β n S n and

[0013] like The setting voltage of the low-voltage trip unit corresponding to motors numbered 1 to n is set to U. d1 The action delay is t d2 ;

[0014] like The maximum number of motors to start, m, is determined according to the motor starting priority, such that: The setting voltage of the low-voltage trip unit corresponding to motors numbered 1 to m is U. d1 The action delay is t d1 The setting voltage of the low-voltage trip unit corresponding to motors numbered m+1 to n is set to U. d2 The action delay is t d2 U d1 <U d2 , t d1 >t d2 .

[0015] Furthermore, in the above technical solution, the maximum permissible voltage drop U of the low-voltage bus is... sag =0.85pu.

[0016] Furthermore, in the above technical solution, U d1 =0.7pu, U d2 =0.85pu.

[0017] Further, in the technical solution, t d1 is the sum of the 6 / 10kV line protection time, the reclosing interval time, the reclosing motor terminal voltage fluctuation time and the sum of the m+1 to n motor tripping terminal voltage fluctuation time; t d2 is the sum of the 6 / 10kV line protection time, the reclosing interval time and the reclosing motor terminal voltage fluctuation time.

[0018] Further, in the technical solution, the 6 / 10kV line protection time is the maximum value of the action time of the 6 / 10kV substation breaker quick-break protection, over-current protection and zero sequence protection.

[0019] Further, in the technical solution, the reclosing interval time comprises a detection time, a reclosing delay time and a breaker execution time.

[0020] Further, in the technical solution, the reclosing motor terminal voltage fluctuation time is 20-30ms; and the m+1 to n motor tripping terminal voltage fluctuation time is 20-30ms.

[0021] Further, in the technical solution, the low-voltage bus is a 380V bus.

[0022] According to a second aspect of the present application, the present application provides a low-voltage tripper protection setting device, comprising: a sorting unit for numbering the motors according to the starting priority; a calculation unit for calculating the minimum short-circuit capacity S min of a low-voltage bus to which the low-voltage tripper is connected; sag comparing β1S1+β2S2+…β n S n with a result generation unit for grouping setting the setting voltage and the action delay of the low-voltage tripper corresponding to the motor according to the comparison result obtained by the calculation unit.

[0023] Further, in the technical solution, the grouping setting of the setting voltage and the action delay of the low-voltage tripper corresponding to the motor comprises:

[0024] If the number of the motor is 1 to n, the setting voltage of the low-voltage tripper corresponding to the motor is set as U d1 , and the action delay is t d2 ;

[0025] If the number of the motor is 1 to n, the setting voltage of the low-voltage tripper corresponding to the motor is set as U , and the action delay is t , the maximum starting motor number m is obtained according to the starting priority of the motor, so as to satisfy: the setting voltage of the low-voltage tripper corresponding to the motor numbered 1 to m is set as Ud1 , the action delay is t d1 ; the setting voltage of the low-voltage release corresponding to the motor numbered m+1 to n is U d2 , the action delay is t d2 , U d1 <U d2 , t d1 >t d2 .

[0026] According to a third aspect of the present application, the present application provides an electronic device, comprising: at least one processor; and a memory connected with the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to cause the at least one processor to perform the low-voltage release protection setting method according to any one of the above technical solutions.

[0027] According to a fourth aspect of the present application, the present application provides a non-transitory computer-readable storage medium, which stores computer-executable instructions for causing a computer to perform the low-voltage release protection setting method according to any one of the above technical solutions.

[0028] Compared with the prior art, the present application has one or more of the following beneficial effects:

[0029] 1. The low-voltage release protection setting method of the present application can effectively avoid the group start failure caused by the decrease of the bus voltage during the start of the low-voltage motor group, and preferentially ensures that important motors do not trip.

[0030] 2. The present application divides the motor group into two categories, one category of motor is set with a higher undervoltage release setting value and a shorter delay, and the other category of motor is set with a lower undervoltage release setting value and a longer delay, the setting value is simple and convenient, and the reliability is high.

[0031] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application and can be implemented according to the content of the specification, at the same time, in order to make the above and other purposes, technical features and advantages of the present application more easily understood, one or more preferred embodiments are listed below, and are described in detail as follows with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of the power grid structure of a certain 6kV feeder to 380V motor.

[0033] Figure 2 is an equivalent circuit diagram of voltage sag caused by motor start.

[0034] Figure 3This is a flowchart of a low-voltage trip unit protection setting method according to an embodiment of the present invention.

[0035] Figure 4 This is a schematic diagram of a low-voltage trip unit protection setting device according to an embodiment of the present invention.

[0036] Figure 5 This is a schematic diagram of the hardware structure of an electronic device for implementing a low-voltage trip unit protection setting method according to an embodiment of the present invention. Detailed Implementation

[0037] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0038] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0039] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “up,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0040] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0041] like Figure 1 As shown, the 6kV incoming line has q outgoing lines after passing through the 6kV busbar. Each outgoing line connects to the 380V busbar after passing through an output circuit breaker, a 6kV feeder, a 6kV / 0.38kV transformer, and a 380V circuit breaker. The 380V busbar has n outgoing lines, which are connected to motors M1, M2...M1 respectively via 380V low-voltage circuit breakers. n Among them, the 380V low-voltage circuit breaker is equipped with a low-voltage trip unit, which has the function of delayed tripping.

[0042] refer to Figure 2As shown, the load fed on the same busbar as the motor M experiences the following voltage: A motor with power S1 is connected to a short-circuit capacity of S. min When the power supply is fed, the system impedance is During startup, the motor impedance is Among them U n β1 is the ratio of the starting current to the normal current, i.e., the starting current multiple. The bus voltage when a motor starts is... When n motors start, the bus voltage is Therefore, the constraint condition for the capacity of the motors that can be started by a certain busbar can be derived as follows:

[0043] The low-voltage trip unit protection setting method according to a specific embodiment of the present invention includes at least the following steps:

[0044] The motors are numbered 1, 2...n according to their starting priority, and their capacities are S1, S2...S... n The starting current multiples are β1, β2...β n ;

[0045] Calculate the minimum short-circuit capacity S of the low-voltage busbar connected to the low-voltage trip unit. min ;

[0046] Set the maximum allowable voltage drop U of the low-voltage bus during motor startup. sag ;

[0047] Compare β1S1+β2S2+…β n S n and

[0048] like The setting voltage of the low-voltage trip unit corresponding to motors numbered 1 to n is set to U. d1 The action delay is t d2 ;

[0049] like The maximum number of motors to start, m, is determined according to the motor starting priority, such that: The setting voltage of the low-voltage trip unit corresponding to motors numbered 1 to m is U. d1 The action delay is t d1 The setting voltage of the low-voltage trip unit corresponding to motors numbered m+1 to n is set to U. d2 The action delay is t d2 U d1 <U d2 , t d1 >t d2.

[0050] Further, in one or more exemplary embodiments of the present application, t d1 is the sum of the 6 / 10 kV line protection time, the reclosing interval time, the reclosing motor terminal voltage fluctuation time, and the m+1 to n motor tripping terminal voltage fluctuation time; t d2 is the sum of the 6 / 10 kV line protection time, the reclosing interval time, and the reclosing motor terminal voltage fluctuation time.

[0051] Further, in one or more exemplary embodiments of the present application, the 6 / 10 kV line protection time is the maximum value of the operation time of the instantaneous protection, the overcurrent protection, and the zero sequence protection of the circuit breaker in the 6 / 10 kV substation. Further, in one or more exemplary embodiments of the present application, the reclosing interval time includes the detection time, the reclosing delay time, and the circuit breaker execution time. Further, in one or more exemplary embodiments of the present application, the reclosing motor terminal voltage fluctuation time is 20-30 ms; and the m+1 to n motor tripping terminal voltage fluctuation time is 20-30 ms.

[0052] The low-voltage tripping device protection setting method, device, memory, and equipment of the present application will be described in more detail below in the manner of specific embodiments. It should be understood that the embodiments are exemplary only, and the present application is not limited thereto.

[0053] Embodiment 1

[0054] In combination Figure 3 with FIG. 1, the flow of the low-voltage tripping device protection setting method according to the present embodiment is as follows:

[0055] The motors are numbered 1, 2, …, n according to the starting priority, and their capacities are S1, S2, …, Sn, respectively, and the starting current multiples are β1, β2, …, βn, respectively. n ; n ;

[0056] The minimum short-circuit capacity S min of the 380V bus to which the low-voltage tripping device is connected is calculated.

[0057] The maximum allowed voltage drop U sag of the low-voltage bus during motor starting is set.

[0058] If the setting voltage of the low-voltage tripping device corresponding to the motor numbered 1 to n is set as U d1 , and the operation delay is t d2 .

[0059] If the motor m satisfying the following conditions is obtained according to the starting priority of the motor: The setting voltage of the low-voltage trip unit corresponding to motors numbered 1 to m is U. d1 The action delay is t d1 The setting voltage of the low-voltage trip unit corresponding to motors numbered m+1 to n is set to U. d2 The action delay is t d2 .

[0060] Among them, the maximum permissible voltage drop value U of the low-voltage bus is sag =0.85pu, U d1 =0.7pu, U d2 =0.85pu. t d1 This is the sum of the protection time of the 6 / 10kV line, the reclosing interval time, the voltage fluctuation time at the reclosing motor terminals, and the voltage fluctuation time at the trip terminals of motors m+1 to n; t d2 It is the sum of the protection time of the 6 / 10kV line, the reclosing interval time, and the voltage fluctuation time at the reclosing motor terminals.

[0061] Example 2

[0062] Combination Figure 4 As shown, the low-voltage trip unit protection setting device in this embodiment includes: a sorting unit 10, which is used to number the motors according to their starting priority; and a calculation unit 20, which is used to calculate the minimum short-circuit capacity S of the low-voltage busbar connected to the low-voltage trip unit. min Set the maximum allowable voltage drop U of the low-voltage bus during motor startup. sag Compare β1S1+β2S2+…β n S n and And a result generation unit 30, which is used to set the setting voltage and action delay of the low-voltage trip unit corresponding to the motor in groups according to the comparison results obtained by the calculation unit 20.

[0063] The setting voltage and operating delay of the low-voltage trip unit corresponding to the motor in the group settings include:

[0064] like The setting voltage of the low-voltage trip unit corresponding to motors numbered 1 to n is set to U. d1 The action delay is t d2 ;

[0065] like The maximum number of motors to start, m, is determined according to the motor starting priority, such that: The setting voltage of the low-voltage trip unit corresponding to motors numbered 1 to m is U. d1 The action delay is t d1; the setting voltage of the low-voltage release corresponding to the motor numbered m+1 to n is U d2 , the action delay is t d2 , U d1 <U d2 , t d1 >t d2 .

[0066] Embodiment 3

[0067] The embodiment provides a non-transitory (non-volatile) computer storage medium, which stores computer executable instructions, the computer executable instructions being capable of executing the method in any method embodiment and achieving the same technical effects.

[0068] Embodiment 4

[0069] The embodiment provides a computer program product, which comprises a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions, when the program instructions are executed by a computer, the computer is caused to execute the method in the above aspects and achieve the same technical effects.

[0070] Embodiment 5

[0071] Figure 5 is a schematic diagram of the hardware structure of the electronic device for executing the low-voltage release protection setting method in the embodiment. The device comprises one or more processors 610 and a memory 620. Taking one processor 610 as an example. The device can also comprise an input device 630 and an output device 640.

[0072] The processor 610, the memory 620, the input device 630 and the output device 640 can be connected through a bus or other means, Figure 5 for example, through a bus connection.

[0073] The memory 620, as a kind of non-transitory computer readable storage medium, can be used to store non-transitory software programs, non-transitory computer executable programs and modules. The processor 610 executes various functional applications and data processing of the electronic device by running the non-transitory software programs, instructions and modules stored in the memory 620, that is, the processing method of the above method embodiment is realized.

[0074] The memory 620 can include a program storage area and a data storage area, where the program storage area can store an operating system, application programs required by at least one function, and the like; the data storage area can store data, and the like. In addition, the memory 620 can include a high-speed random access memory, and can also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state memory device. In some embodiments, the memory 620 can optionally include a memory disposed remotely with respect to the processor 610, which can be connected to the processing device through a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0075] The input device 630 can receive input digital or character information, and generate a signal input. The output device 640 can include a display device such as a display screen.

[0076] The one or more modules are stored in the memory 620 and, when executed by the one or more processors 610, perform the following:

[0077] The motors are numbered 1, 2, …, n according to the starting priority, and their capacities are S1, S2, …, S n , and the starting current multiples are β1, β2, …, β n , respectively.

[0078] The minimum short-circuit capacity S min of the low-voltage bus connected to the low-voltage release is calculated.

[0079] The maximum allowed drop value U sag of the voltage of the low-voltage bus during motor starting is set.

[0080] β1S1+β2S2+…β n S n is compared with

[0081] If the setting voltage of the low-voltage release corresponding to the motor numbered 1 to n is set to U d1 , and the action delay is t d2 .

[0082] If the maximum number of starting motors m is obtained according to the starting priority of the motor, so as to satisfy: the setting voltage of the low-voltage release corresponding to the motor numbered 1 to m is set to U d1 , and the action delay is t d1 ; the setting voltage of the low-voltage release corresponding to the motor numbered m+1 to n is set to U d2 , and the action delay is t d2 , and Ud1 <U d2 ,t d1 >t d2 .

[0083] The product can perform the method provided by the embodiment of the application, has the corresponding function modules and beneficial effects of performing the method. Technical details not described in detail in the embodiment can be referred to the method provided by other embodiments of the application.

[0084] The device embodiments described above are only schematic, and the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e. can be located in one place, or can be distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0085] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software plus a general hardware platform, and of course can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, and the computer software product can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0086] The foregoing description of specific exemplary embodiments of the application is provided for the purpose of explanation and illustration. These descriptions are not intended to limit the application to the precise forms disclosed, and many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application, and to allow others skilled in the art to understand the application to implement and utilize in various embodiments and with various modifications as are suited to the particular use contemplated. Any simple modification, equivalent replacement, and modification of the above-described exemplary embodiments should fall within the scope of the application.

Claims

1. A low voltage release protection setting method, characterized by, At least comprising the following steps: The motors are numbered 1, 2, … n according to the starting priority, and their capacities are S1, S2, … Sn respectively n , and the starting current multiples are β1, β2, … βn respectively n ; calculating the minimum short-circuit capacity S of a low-voltage busbar to which the low-voltage release is connected min ; The maximum allowed drop value U of the voltage of the low voltage bus at the time of motor start-up is set sag ; Comparing β1S1+β2S2+...β n S n With If The setting voltage of the low-voltage release corresponding to the motor numbered 1 to n is set to U d1 , and the action delay is t d2 ; If The maximum number of starting motors m is obtained according to the starting priority of the motors, so as to satisfy The setting voltage of the low-voltage release corresponding to the motors numbered 1 to m is set as U d1 , and the action delay is t d1 ; the setting voltage of the low-voltage release corresponding to the motors numbered m+1 to n is set as U d2 , and the action delay is t d2 , U d1 <U d2 , and t d1 >t d2 .

2. The low voltage release protection setting method of claim 1, wherein, The maximum allowed drop value U of the voltage of the low-voltage bus sag = 0.85 p.u.

3. The low voltage release protection setting method of claim 1, wherein, U d1 = 0.7 p.u., U d2 = 0.85 p.u.

4. The low voltage release protection setting method of claim 1, wherein, t d1 is the sum of the 6 / 10 kV line protection time, the reclosing interval time, the reclosing motor terminal voltage fluctuation time, and the m+1 to n motor tripping terminal voltage fluctuation time; t d2 is the sum of the 6 / 10 kV line protection time, the reclosing interval time, and the reclosing motor terminal voltage fluctuation time.

5. The low voltage release protection setting method of claim 4, wherein, The 6 / 10kV line protection time is the maximum value of the action time of the 6 / 10kV substation circuit breaker quick-break protection, over-current protection and zero sequence protection.

6. The low voltage release protection setting method of claim 4, wherein, The reclosing interval time comprises a detection time, a reclosing delay time and a circuit breaker execution time.

7. The low voltage release protection setting method of claim 4, wherein, The reclosing motor terminal voltage fluctuation time is 20-30ms; the m+1 to n number motor tripping terminal voltage fluctuation time is 20-30ms.

8. The low voltage release protection setting method of claim 1, wherein, The low-voltage bus is a 380V bus.

9. A low voltage release protection setting device, characterized in that The method comprises the following steps: A sorting unit is arranged for numbering the motors according to the starting priority; a computing unit for calculating a minimum short-circuit capacity S of a low-voltage bus to which the low-voltage release is connected min setting a maximum permissible drop value U of the voltage of the low-voltage bus at the time of motor starting sag comparing β1S1+ β2S+2... βS n with A result generating unit is arranged for grouping setting the setting voltage and action delay of the low-voltage tripper corresponding to the motor according to the comparison result obtained by the calculating unit.

10. The low-voltage release protection setting device of claim 9, wherein, The grouping setting of the setting voltage and action delay of the low-voltage tripper corresponding to the motor comprises: If The setting voltage of the low-voltage release corresponding to the motor numbered 1 to n is set to U d1 , and the action delay is t d2 ; If The number of starting motors m is obtained according to the starting priority of the motors, so as to satisfy The setting voltage of the low-voltage release corresponding to the motors numbered 1 to m is set as U d1 , and the action delay is t d1 ; the setting voltage of the low-voltage release corresponding to the motors numbered m+1 to n is set as U d2 , and the action delay is t d2 , U d1 <U d2 , and t d1 >t d2 .

11. An electronic device, comprising: Comprising: At least one processor; And A memory connected in communication with the at least one processor; wherein, The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to cause the at least one processor to perform the low-voltage tripper protection setting method according to any one of claims 1-8.

12. A non-transitory computer-readable storage medium, comprising: The non-transitory computer readable storage medium stores computer executable instructions for causing the computer to perform the low-voltage tripper protection setting method according to any one of claims 1-8.

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