CN111243226A - Personal safety assessment method and system under single-phase broken line tower grounding fault - Google Patents

Personal safety assessment method and system under single-phase broken line tower grounding fault Download PDF

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CN111243226A
CN111243226A CN202010113717.2A CN202010113717A CN111243226A CN 111243226 A CN111243226 A CN 111243226A CN 202010113717 A CN202010113717 A CN 202010113717A CN 111243226 A CN111243226 A CN 111243226A
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area
tower
micro
segment
grounding device
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CN111243226B (en
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方正云
黄继盛
马御棠
马仪
周利军
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Electric Power Research Institute of Yunnan Power Grid Co Ltd
Yunnan Power Grid Co Ltd
Lincang Power Supply Bureau of Yunnan Power Grid Co Ltd
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Electric Power Research Institute of Yunnan Power Grid Co Ltd
Yunnan Power Grid Co Ltd
Lincang Power Supply Bureau of Yunnan Power Grid Co Ltd
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/02—Alarms for ensuring the safety of persons
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/12—Measuring electrostatic fields or voltage-potential
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
    • G06N3/00—Computing arrangements based on biological models
    • G06N3/12—Computing arrangements based on biological models using genetic models
    • G06N3/126—Evolutionary algorithms, e.g. genetic algorithms or genetic programming
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B7/00—Signalling systems according to more than one of groups G08B3/00 - G08B6/00; Personal calling systems according to more than one of groups G08B3/00 - G08B6/00
    • G08B7/06—Signalling systems according to more than one of groups G08B3/00 - G08B6/00; Personal calling systems according to more than one of groups G08B3/00 - G08B6/00 using electric transmission, e.g. involving audible and visible signalling through the use of sound and light sources

Abstract

The invention relates to a personal safety assessment method and a personal safety assessment system under the condition of single-phase broken line grounding fault through a tower, wherein the personal safety assessment system comprises a current sensor, an LED alarm lamp, a multi-tone loudspeaker, a projection lamp, a power supply module, a central processing unit and an amplifying circuit; the power supply module is connected with the central processing unit; the central processing unit is respectively connected with the current sensor, the fault LED alarm lamp, the projection lamp and the amplifying circuit; the amplifying circuit is also connected with the polyphonic loudspeaker; the invention measures the fault current of single-phase broken line earthed through the pole tower through the current sensor, and inputs the fault current to the central processing unit to calculate the step voltage, and divides the dangerous area of the step voltage according to the current which can be born by human body; in addition, the invention can also give an alarm through an LED alarm lamp and a polyphonic loudspeaker, project a corresponding dangerous area on the ground and is easy to popularize and apply.

Description

Personal safety assessment method and system under single-phase broken line tower grounding fault
Technical Field
The invention belongs to the technical field of grounding analysis of power systems, and particularly relates to a personal safety assessment method and system for single-phase broken line through tower grounding faults.
Background
The distribution network is the core part of the power system, and the stable and reliable operation of the distribution network is closely related to reliable power utilization and personal safety of people. The single-phase earth fault occupies a considerable part of all faults of a distribution network, when the single-phase earth fault occurs through a tower, the faulty operation of the system can cause the continuous existence of the earth current, the personal safety can be seriously threatened, and even the life danger can be caused.
The problem of the single-phase disconnection fault of the distribution network is always solved. At present, many researches aiming at single-phase earth faults exist at home and abroad, mainly focusing on earth resistance testing, step voltage and contact voltage distribution calculation and the like, but the researches on an alarm system or a method for evaluating personal safety are lacked. In order to effectively guarantee personal safety, an intelligent diversified alarm method is urgently needed, the condition of electric shock danger in a fault area can be evaluated, and risk early warning is timely sent out.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provides a personal safety evaluation method and system for a single-phase broken line under the condition of tower grounding fault.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a personal safety evaluation system for a single-phase broken line under tower earth fault comprises a current sensor, an L ED alarm lamp, a multi-tone horn, a projection lamp, a power supply module, a central processing unit and an amplifying circuit;
the power supply module is connected with the central processing unit;
the central processing unit is respectively connected with the current sensor, the fault LED alarm lamp, the projection lamp and the amplifying circuit;
the amplifying circuit is also connected with the polyphonic loudspeaker;
the central processing unit is used for calculating according to the data acquired by the current sensor; the calculation method is as follows:
(1) calculating any P of soil area around fault toweriPoint potential value VPi：
Setting the total circumference of the square grounding device II of the tower as L, dividing L into n micro-segments with the same size, and setting the length of the jth micro-segment as LjThus, any P in the soil area near the toweriPoint generated potential value VPiCalculated from the following formula:
Figure BDA0002390842390000021
① when PiWhen the point is located outside the area right above the square grounding device:
Figure BDA0002390842390000022
② when PiWhen the point is located in the area right above the square grounding device, the micro-segment j is divided into m micro-segments with equal size:
Figure BDA0002390842390000023
in the formulae (1) to (3), RPjIs a mutual resistance whose value is defined as the point P when the unit current source is applied to the jth micro-segmentiThe resulting potential; because the grounding device is not completely contacted with the soil closely, a contact layer formed by soil particles and air gaps exists, rho0Is the contact layer resistivity; h is0Is the contact layer thickness; i is the total current of the inlet font grounding device; rho is the soil resistivity; r and r' are points PiDistance r, r 'from the center point of the j-th micro-segment and its mirror image point'>>Lj(ii) a k denotes the kth micro-segment of micro-segment j, dj kIs the current flowing into the soil from the kth differential section of the differential section j; a is the conductor radius of the square grounding device, and b is the length of the kth differential segment; taking the geometric center of the square grounding device as the origin of coordinates, drawing an x coordinate axis along the extension of the transmission line to a front tower, drawing a y coordinate axis along the x coordinate axis by rotating 90 degrees anticlockwise, drawing a z coordinate axis perpendicular to the soil surface, and drawing x coordinate axis0、 y0、z0Respectively the position coordinate, x, of the center point of the jth micro-segment1、y1、z1Are respectively PiThe position coordinates of the points; k0And K1A second class of modified Bessel functions of zero order and first order, respectively; λ is an integral variable; g is the number of calculation points, and c is a correction coefficient;
(2) via P (P) at an arbitrary distance of 1m1，q1，r1)、Q(p2，q2，r2) Calculating the current value I passing through the human body by the potential difference of the two pointsP：
Figure BDA0002390842390000024
Figure BDA0002390842390000025
In the formula (5), VP、VQP, Q for two points of potential; rinIs in the human bodyPartial resistance, R0Is the human skin resistance; b1Is the equivalent grounding radius of the human body;
in the formula (6), D is the maximum value of the horizontal distance from P, Q two points to the center of the square grounding device;
(3) dividing a step voltage dangerous area according to the bearable current of a human body:
when I isPWhen the current value is 100mA, D is calculated corresponding to P, Q two points1(ii) a All the same asPWhen D is 25mA, D is D2； IPWhen D is 6mA, D is D3；IPWhen 1mA, D is D4；
When I isP>100mA, i.e. D<D1When this area is at first-class risk, death results; when 25 is turned on<IP<100m A, i.e. D1<D<D2At the same time, the area is at second-class danger, which causes muscle contraction and dyspnea; when 6 is<IP<25mA, i.e. D2<D<D3At the time, the area is at risk of three, leading to intolerance of pain; when 1 is<IP<6mA, i.e. D3<D<D4At the time, the area is at risk of four, causing slight stinging; when I isP<1mA, i.e. D>D4When the area is a safe area;
then, according to the calculation result, light alarm is carried out through an LED alarm lamp, and each area is projected through a projection lamp to carry out warning;
the amplifying circuit is used for amplifying the audio signal transmitted by the central processing unit and then carrying out sound alarm through the multi-tone loudspeaker.
Further, it is preferable that the power supply module includes a solar panel, a battery, and a power supply protection circuit;
the solar panel and the power supply protection circuit are respectively connected with the battery.
Further, the battery is preferably a rechargeable lithium battery.
Further, it is preferable that the projection lamp projects the respective areas in the form of different colored rings for warning.
Further, it is preferable that the wireless communication device further comprises a wireless transmission module;
the wireless transmission module is connected with the central processing unit and used for wirelessly uploading the fault information to the power department.
Further, it is preferable that the value of c is calculated by the following algorithm:
(A) initialization: setting an evolution algebra counter G0Setting the maximum evolution algebra G to be 100, and randomly generating 50 different c values as an initial population P (0);
(B) individual evaluation: calculating the fitness f (c) of each individual in the population according to the formula;
Figure BDA0002390842390000031
wherein, V'PiIs a point PiCalculating the potential according to the existing theory;
(C) genetic operation: according to the fitness of each individual in the group, carrying out selection, crossing and mutation operations to generate a new generation of individuals;
(D) if G is0G is less than or equal to G, then G0＝G0+1, go to step (B); if G is0If the fitness is more than G, outputting the individual c with the maximum fitness obtained in the evolution process as the optimal solution, and stopping calculation.
The personal safety evaluation method under the condition that the single-phase broken line passes through the tower earth fault comprises the following steps:
(1) calculating any P of soil area around fault toweriPoint potential value VPi：
Setting the total circumference of the square grounding device II of the tower as L, dividing L into n micro-segments with the same size, and setting the length of the jth micro-segment as LjThus, any P in the soil area near the toweriPoint generated potential value VPiCalculated from the following formula:
Figure BDA0002390842390000041
① when PiWhen the point is located outside the area right above the square grounding device:
Figure BDA0002390842390000042
② when PiWhen the point is located in the area right above the square grounding device, the micro-segment j is divided into m micro-segments with equal size:
Figure BDA0002390842390000043
in the formulae (1) to (3), RPjIs a mutual resistance whose value is defined as the point P when the unit current source is applied to the jth micro-segmentiThe resulting potential; because the grounding device is not completely contacted with the soil closely, a contact layer formed by soil particles and air gaps exists, rho0Is the contact layer resistivity; h is0Is the contact layer thickness; i is the total current of the inlet font grounding device; rho is the soil resistivity; r and r' are points PiDistance r, r 'from the center point of the j-th micro-segment and its mirror image point'>>Lj(ii) a k denotes the kth micro-segment of micro-segment j, dj kIs the current flowing into the soil from the kth differential section of the differential section j; a is the conductor radius of the square grounding device, and b is the length of the kth differential segment; taking the geometric center of the square grounding device as the origin of coordinates, drawing an x coordinate axis along the extension of the transmission line to a front tower, drawing a y coordinate axis along the x coordinate axis by rotating 90 degrees anticlockwise, drawing a z coordinate axis perpendicular to the soil surface, and drawing x coordinate axis0、 y0、z0Respectively the position coordinate, x, of the center point of the jth micro-segment1、y1、z1Are respectively PiThe position coordinates of the points; k0And K1A second class of modified Bessel functions of zero order and first order, respectively; λ is an integral variable; g is the number of calculation points, and c is a correction coefficient;
(2) via P (P) at an arbitrary distance of 1m1，q1，r1)、Q(p2，q2，r2) Calculating the current value I passing through the human body by the potential difference of the two pointsP：
Figure BDA0002390842390000044
Figure BDA0002390842390000051
In the formula (5), VP、VQP, Q for two points of potential; rinIs an internal resistance of the human body, R0Is the human skin resistance; b1Is the equivalent grounding radius of the human body;
in the formula (6), D is the maximum value of the horizontal distance from P, Q two points to the center of the square grounding device;
(3) dividing a step voltage dangerous area according to the bearable current of a human body:
when I isPWhen the current value is 100mA, D is calculated corresponding to P, Q two points1(ii) a All the same asPWhen D is 25mA, D is D2； IPWhen D is 6mA, D is D3；IPWhen 1mA, D is D4；
When I isP>100mA, i.e. D<D1When this area is at first-class risk, death results; when 25 is turned on<IP<100m A, i.e. D1<D<D2At the same time, the area is at second-class danger, which causes muscle contraction and dyspnea; when 6 is<IP<25mA, i.e. D2<D<D3At the time, the area is at risk of three, leading to intolerance of pain; when 1 is<IP<6mA, i.e. D3<D<D4At the time, the area is at risk of four, causing slight stinging; when I isP<1mA, i.e. D>D4When the area is a safe area;
further, it is preferable that the value of c is calculated by the following algorithm:
(A) initialization: setting an evolution algebra counter G0Setting the maximum evolution algebra G to be 100, and randomly generating 50 different c values as an initial population P (0);
(B) individual evaluation: calculating the fitness f (c) of each individual in the population according to the formula;
Figure BDA0002390842390000052
wherein, V'PiIs a point PiCalculating the potential of the real sample;
(C) genetic operation: according to the fitness of each individual in the population, adopting MATLAB default selection, crossing and mutation operations to generate a new generation of individuals;
(D) if G is0G is less than or equal to G, then G0＝G0+1, go to step (B); if G is0If the fitness is more than G, outputting the individual c with the maximum fitness obtained in the evolution process as the optimal solution, and stopping calculation.
When I isP>100mA, i.e. D<D1When this area is at first-class risk, death results; when 25 is turned on<IP<100mA, i.e. D1<D<D2At the same time, the area is at second-class danger, which causes muscle contraction and dyspnea; when 6 is<IP<25mA, i.e. D2<D<D3At the time, the area is at risk of three, leading to intolerance of pain; when 1 is<IP<6mA, i.e. D3<D<D4At the time, the area is at risk of four, causing slight stinging; when I isP<1mA, i.e. D>D4When the area is a safe area;
compared with the prior art, the invention has the beneficial effects that:
1) the actual condition of the power distribution network with the disconnection and grounding faults can be effectively simulated;
2) the potential of the surrounding soil under the fault of the power transmission line broken line connecting rod tower can be effectively calculated;
3) the influence of a human equivalent circuit and contact resistance can be fully considered when the earth surface potential is calculated.
4) The dangerous area causing the electric shock accident of the human body can be divided;
5) can carry out audible and visual alarm to the dangerous condition through alarm device to carry out the projection of danger area on ground, the alarm mode is novel effective.
Drawings
FIG. 1 is a schematic diagram of the system architecture of the present invention;
FIG. 2 is a schematic diagram of the system of the present invention in use according to an embodiment;
FIG. 3 is a schematic view of the system installation of the present invention;
wherein, 1, tower I; 2. a second tower; 3. a third tower; 4. a first power transmission line; 5. a second power transmission line; 6. breaking a first wire; 7. a second wire is broken; 8. a third power transmission line; 9. a fourth power transmission line; 10. a fifth power transmission line; 11. a square grounding device I; 12. a square grounding device II; 13. a square grounding device III; 14. soil is homogenized; 15. the system of the invention;
100. a housing; 101. a current sensor; 102. a first fastener; 103. a second fastener; 104. an LE D alarm lamp; 105. a polyphonic loudspeaker; 106. a projection lamp; 107. a solar panel; 108. a wireless transmission module; 109. a support bar; 110. a first screw; 111. a second screw; 112. a third screw; 113. a fourth screw; 200. an internal circuit; 201. a power supply module; 202. a central processing unit; 203. a battery; 204. a power supply protection circuit; 205. an amplifying circuit.
Detailed Description
The present invention will be described in further detail with reference to examples.
It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples do not specify particular techniques or conditions, and are performed according to the techniques or conditions described in the literature in the art or according to the product specifications. The materials or equipment used are not indicated by manufacturers, and all are conventional products available by purchase.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
In the description of the present invention, "a plurality" means two or more unless otherwise specified. The terms "inner," "upper," "lower," and the like, refer to an orientation or a state relationship based on that shown in the drawings, which is for convenience in describing and simplifying the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "provided" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. To those of ordinary skill in the art, the specific meanings of the above terms in the present invention are understood according to specific situations.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
As shown in fig. 1, a personal safety evaluation system for a single-phase broken line passing through a tower ground fault includes a current sensor 101, an LED alarm lamp 104, a multitone horn 105, a projection lamp 106, a power module 201, a central processing unit 202, and an amplification circuit 205;
the power supply module 201 is connected with the central processing unit 202;
the central processing unit 202 is respectively connected with the current sensor 101, the fault LED alarm lamp 104, the projection lamp 106 and the amplifying circuit 205;
the amplifying circuit 205 is also connected to the polyphonic loudspeaker 105;
the central processing unit 202 is used for calculating according to the data collected by the current sensor 101; the calculation method is as follows:
(1) calculating any P of soil area around fault toweriPoint potential value VPi：
Setting the total circumference of the square grounding device II of the tower as L, dividing L into n micro-segments with the same size, and setting the length of the jth micro-segment as LjThus, any P in the soil area near the toweriPoint generated potential value VPiCalculated from the following formula:
Figure BDA0002390842390000071
① when PiWhen the point is located outside the area right above the square grounding device:
Figure BDA0002390842390000081
② when PiWhen the point is located in the area right above the square grounding device, the micro-segment j is divided into m micro-segments with equal size:
Figure BDA0002390842390000082
in the formulae (1) to (3), RPjIs a mutual resistance whose value is defined as the point P when the unit current source is applied to the jth micro-segmentiThe resulting potential; because the grounding device is not completely contacted with the soil closely, a contact layer formed by soil particles and air gaps exists, rho0Is the contact layer resistivity; h is0Is the contact layer thickness; i is the total current of the inlet font grounding device; rho is the soil resistivity; r and r' are points PiDistance r, r 'from the center point of the j-th micro-segment and its mirror image point'>>Lj(ii) a k denotes the kth micro-segment of micro-segment j, dj kIs the current flowing into the soil from the kth differential section of the differential section j; a is the conductor radius of the square grounding device, b is the k-th differentialA segment length; taking the geometric center of the square grounding device as the origin of coordinates, drawing an x coordinate axis along the extension of the transmission line to a front tower, drawing a y coordinate axis along the x coordinate axis by rotating 90 degrees anticlockwise, drawing a z coordinate axis perpendicular to the soil surface, and drawing x coordinate axis0、 y0、z0Respectively the position coordinate, x, of the center point of the jth micro-segment1、y1、z1Are respectively PiThe position coordinates of the points; k0And K1A second class of modified Bessel functions of zero order and first order, respectively; λ is an integral variable; g is the number of calculation points, and c is a correction coefficient;
the value of c is calculated by the following algorithm:
(A) initialization: setting an evolution algebra counter G0Setting the maximum evolution algebra G to be 100, and randomly generating 50 different c values as an initial population P (0);
(B) individual evaluation: calculating the fitness f (c) of each individual in the population according to the formula;
Figure BDA0002390842390000083
wherein, V'PiIs a point PiCalculating the potential according to the existing theory;
(C) genetic operation: selecting, crossing and mutating by adopting MATLAB default according to the fitness of each individual in a group to generate a new generation of individuals;
(D) if G is0G is less than or equal to G, then G0＝G0+1, go to step (B); if G is0If the fitness is more than G, outputting the individual c with the maximum fitness obtained in the evolution process as an optimal solution, and stopping calculation;
(2) via P (P) at an arbitrary distance of 1m1，q1，r1)、Q(p2，q2，r2) Calculating the current value I passing through the human body by the potential difference of the two pointsP：
Figure BDA0002390842390000091
Figure BDA0002390842390000092
In the formula (5), VP、VQP, Q for two points of potential; rinIs an internal resistance of the human body, R0Is the human skin resistance; b1Is the equivalent grounding radius of the human body;
in the formula (6), D is the maximum value of the horizontal distance from P, Q two points to the center of the square grounding device;
(3) dividing a step voltage dangerous area according to the bearable current of a human body:
when I isPWhen the current value is 100mA, D is calculated corresponding to P, Q two points1(ii) a All the same asPWhen D is 25mA, D is D2； IPWhen D is 6mA, D is D3；IPWhen 1mA, D is D4；
When I isP>100mA, i.e. D<D1When this area is at first-class risk, death results; when 25 is turned on<IP<100m A, i.e. D1<D<D2At the same time, the area is at second-class danger, which causes muscle contraction and dyspnea; when 6 is<IP<25mA, i.e. D2<D<D3At the time, the area is at risk of three, leading to intolerance of pain; when 1 is<IP<6mA, i.e. D3<D<D4At the time, the area is at risk of four, causing slight stinging; when I isP<1mA, i.e. D>D4When the area is a safe area;
then, according to the calculation result, light alarm is carried out through an LED alarm lamp 104, and each area is projected through a projection lamp 106 for warning;
the amplifier circuit 205 is used to amplify the audio signal from the cpu 202 and then make an audible alarm through the polyphonic speaker 105.
Preferably, the power module 201 includes a solar panel 107, a battery 203 and a power protection circuit 204;
the solar panel 107 and the power protection circuit 204 are respectively connected to the battery 203.
The power protection circuit 204 is used for protecting the power supply
Preferably, the battery 203 is a rechargeable lithium battery.
Preferably, the projection lamp 106 projects the various zones in the form of different colored rings for warning purposes.
Preferably, the system further comprises a wireless transmission module 108;
the wireless transmission module 108 is connected to the central processing unit 202, and is configured to wirelessly upload the fault information to the power department.
Examples of the applications
As shown in fig. 2 to fig. 3, the first transmission line 4 and the third transmission line 8, the second transmission line 5 and the fourth transmission line 9 are A, B two-phase transmission lines in a normal state, the fifth transmission line 10 is a C-phase transmission line in a normal state, the first broken line 6 and the second broken line 7 are C-phase transmission lines in a broken state, the first broken line 6 is suspended, the second broken line 7 is in contact with the second tower 2, and fault current is dissipated through the second grounding device 12;
the first tower 1, the second tower 2 and the third tower 3 are connected with each other through a first transmission line 4, a second transmission line 5, a third transmission line 8, a fourth transmission line 9 and a fifth transmission line 10, and tower feet of the first tower 1, the second tower 2 and the third tower 3 are respectively connected with a first square grounding device 11, a second square grounding device 12 and a third square grounding device 13;
the current sensor 101 is fixed at the tower foot of a second tower 2 and can collect the size of the ground current after the single-phase broken line of the power transmission line is connected with the tower; preferably, the current sensor 101 transmits the current data to the central processing unit 202 through the BNC connector.
Solar panel 107 is mounted on the right side of housing 100; the projection lamp 106 is arranged right below the shell 100 and connected with the bottom of the shell 100; the LED alarm lamp 104 and the wireless transmission module 108 are arranged at the outer top of the shell 100; the polyphonic horn 105 is mounted at a lower portion of the front surface of the housing 100. The battery 203, the power protection circuit 204, the central processing unit 202, and the amplifier circuit 205 are mounted in the housing 100.
The projection lamp 106 is connected to the bottom of the housing 100 through a support rod 109; the upper end of the supporting rod 109 is fixedly connected with the bottom of the shell 100 through a third screw 112 and a fourth screw 113; the lower end of the supporting rod 109 is fixedly connected with the projection lamp 106 through a first screw 110 and a second screw 111. Namely, the projection lamp 106 is suspended right below the housing 100;
the tower crane further comprises a first fastening piece 102 and a second fastening piece 103, wherein the first fastening piece 102 and the second fastening piece 103 are both arranged on the left side of the shell 100 and are fixed on the second tower 2.
The wireless transmission module 108, the power module 201, the central processing unit 202 and the amplifying circuit 205 together form an internal circuit 200.
Calculating any P of soil area around fault toweriPoint potential value VPi：
When the single-phase line of the distribution network line is disconnected and grounded through the second tower 2, the fault current I flows to the uniform soil 14 through the second tower 2 through the second square grounding device 12, the total circumference of the second square grounding device 12 is L, the L is divided into n micro-sections with the same size, and the length of the jth micro-section is LjTherefore, any P in the soil area near the second tower 2iPoint generated potential value VPiCalculated from the following formula:
Figure BDA0002390842390000101
③ when PiWhen the point is positioned outside the area right above the square grounding device II 12:
Figure BDA0002390842390000111
④ when PiWhen the point is located in the area right above the square grounding device, the micro-segment j is divided into m micro-segments with equal size:
Figure BDA0002390842390000112
in the formulae (1) to (3), RPjIs a mutual resistance whose value is defined as the point P when the unit current source is applied to the jth micro-segmentiThe resulting potential; because the grounding device is not completely contacted with the soil closely, a contact layer formed by soil particles and air gaps exists, rho0Is the contact layer resistivity; h is0Is the contact layer thickness; i is the total current of the inlet font grounding device; rho is the soil resistivity; r and r' are points PiDistance r, r 'from the center point of the j-th micro-segment and its mirror image point'>>Lj(ii) a k denotes the kth micro-segment of micro-segment j, dj kIs the current flowing into the soil from the kth differential section of the differential section j; a is the conductor radius of the square grounding device, and b is the length of the kth differential segment; taking the geometric center of the square grounding device II 12 as the origin of coordinates, extending along the transmission line to the first tower 1 to draw an x coordinate axis, anticlockwise rotating by 90 degrees along the x coordinate axis to draw a y coordinate axis, drawing a z coordinate axis perpendicular to the soil surface, and drawing x coordinate axis0、y0、z0Respectively the position coordinate, x, of the center point of the jth micro-segment1、y1、z1Are respectively PiThe position coordinates of the points; k0And K1A second class of modified Bessel functions of zero order and first order, respectively; λ is an integral variable; g is the number of calculation points, and c is a correction coefficient;
the value of c is calculated by the following algorithm:
(A) initialization: setting an evolution algebra counter G0Setting the maximum evolution algebra G to be 100, and randomly generating 50 different c values as an initial population P (0);
(B) individual evaluation: calculating the fitness f (c) of each individual in the population according to the formula;
Figure BDA0002390842390000113
wherein, V'PiIs a point PiCalculating the potential according to the existing theory;
(C) genetic operation: selecting, crossing and mutating by adopting MATLAB default according to the fitness of each individual in a group to generate a new generation of individuals;
(D) if G is0G is less than or equal to G, then G0＝G0+1, go to step (B); if G is0If the fitness is more than G, outputting the individual c with the maximum fitness obtained in the evolution process as an optimal solution, and stopping calculation;
via P (P) at an arbitrary distance of 1m1，q1，r1)、Q(p2，q2，r2) Calculating the current value I passing through the human body by the potential difference of the two pointsP：
Figure BDA0002390842390000121
Figure BDA0002390842390000122
In the formula (11), VP、VQP, Q for two points of potential; rinIs an internal resistance of the human body, R0Is the human skin resistance; b1Is the equivalent grounding radius of the human body;
in the formula (12), D is the maximum value of the horizontal distance from P, Q two points to the center of the square grounding device;
dividing a step voltage dangerous area according to the bearable current of a human body:
when I isPWhen the current value is 100mA, D is calculated corresponding to P, Q two points1(ii) a All the same asPWhen D is 25mA, D is D2； IPWhen D is 6mA, D is D3；IPWhen 1mA, D is D4；
When I isP>100mA, i.e. D<D1When this area is at first-class risk, death results; when 25 is turned on<IP<100m A, i.e. D1<D<D2At the same time, the area is at second-class danger, which causes muscle contraction and dyspnea; when 6 is<IP<25mA, i.e. D2<D<D3At the time, the area is at risk of three, leading to intolerance of pain; when 1 is<IP<6mA, i.e. D3<D<D4At the time, the area is at risk of four, causing slight stinging; when I isP<1mA, i.e. D>D4When the area is a safe area;
assuming that the fault current I is 10A, the soil resistivity ρ is 100 Ω, m, the side length of the square grounding device is 1m, the radius a is 0.08m, and the buried depth is 0.8m, L is 4 × 1 is 4m, and L is divided into 40 micro-segments on average, thenThe length of each micro-segment is 0.1m, each micro-segment is divided into two micro-segments, the length of each micro-segment is 0.05m, and the thickness h of the contact layer00.002m, contact layer resistivity ρ0300 Ω. Randomly selecting 10 points to calculate the earth surface potential, and optimizing to obtain c-0.8534.
Selecting a point P coordinate (3,0,0.8) which is positioned right above the grounding device; the coordinate of the point Q is (4,0, 0.8); get VP≈40.7V，VQ≈31.49V；
Assuming skin resistance R0Is 250 Ω, and I is obtained from the formula (11)P＝7.02mA；
From formula (12) to give D-4 m, 6<IP<25mA, which is a three-risk area, and can cause pain intolerance.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (8)

1. A personal safety evaluation system for a single-phase broken line under tower earth fault is characterized by comprising a current sensor (101), an LED alarm lamp (104), a multi-tone loudspeaker (105), a projection lamp (106), a power supply module (201), a central processing unit (202) and an amplifying circuit (205);
the power supply module (201) is connected with the central processing unit (202);
the central processing unit (202) is respectively connected with the current sensor (101), the fault LED alarm lamp (104), the projection lamp (106) and the amplifying circuit (205);
the amplifying circuit (205) is also connected with the polyphonic loudspeaker (105);
the central processing unit (202) is used for calculating according to the data collected by the current sensor (101); the calculation method is as follows:
(1) calculate the reasonRandom P of soil area around barrier toweriPoint potential value VPi：
Setting the total circumference of the square grounding device II of the tower as L, dividing L into n micro-segments with the same size, and setting the length of the jth micro-segment as LjThus, any P in the soil area near the toweriPoint generated potential value VPiCalculated from the following formula:
Figure FDA0002390842380000011
① when PiWhen the point is located outside the area right above the square grounding device:
Figure FDA0002390842380000012
② when PiWhen the point is located in the area right above the square grounding device, the micro-segment j is divided into m micro-segments with equal size:
Figure FDA0002390842380000013
in the formulae (1) to (3), RPjIs a mutual resistance whose value is defined as the point P when the unit current source is applied to the jth micro-segmentiThe resulting potential; because the grounding device is not completely contacted with the soil closely, a contact layer formed by soil particles and air gaps exists, rho0Is the contact layer resistivity; h is0Is the contact layer thickness; i is the total current of the inlet font grounding device; rho is the soil resistivity; r and r' are points PiDistance r, r 'from the center point of the j-th micro-segment and its mirror image point'>>Lj(ii) a k denotes the kth micro-segment of micro-segment j, dj kIs the current flowing into the soil from the kth differential section of the differential section j; a is the conductor radius of the square grounding device, and b is the length of the kth differential segment; taking the geometric center of the square grounding device as the origin of coordinates, drawing an x coordinate axis along the extension of the transmission line to a front tower, drawing a y coordinate axis along the x coordinate axis by rotating 90 degrees anticlockwise, and drawing a z coordinate perpendicular to the soil surfaceAxis, x0、y0、z0Respectively the position coordinate, x, of the center point of the jth micro-segment1、y1、z1Are respectively PiThe position coordinates of the points; k0And K1A second class of modified Bessel functions of zero order and first order, respectively; λ is an integral variable; g is the number of calculation points, and c is a correction coefficient;
(2) via P (P) at an arbitrary distance of 1m1，q1，r1)、Q(p2，q2，r2) Calculating the current value I passing through the human body by the potential difference of the two pointsP：
Figure FDA0002390842380000021
Figure FDA0002390842380000022
In the formula (5), VP、VQP, Q for two points of potential; rinIs an internal resistance of the human body, R0Is the human skin resistance; b1Is the equivalent grounding radius of the human body;
in the formula (6), D is the maximum value of the horizontal distance from P, Q two points to the center of the square grounding device;
(3) dividing a step voltage dangerous area according to the bearable current of a human body:
when I isPWhen the current value is 100mA, D is calculated corresponding to P, Q two points1(ii) a All the same asPWhen D is 25mA, D is D2；IPWhen D is 6mA, D is D3；IPWhen 1mA, D is D4；
When I isP>100mA, i.e. D<D1When this area is at first-class risk, death results; when 25 is turned on<IP<100mA, i.e. D1<D<D2At the same time, the area is at second-class danger, which causes muscle contraction and dyspnea; when 6 is<IP<25mA, i.e. D2<D<D3At the time, the area is at risk of three, leading to intolerance of pain; when 1 is<IP<6mA, i.e. D3<D<D4At the time, the area is at risk of four, causing slight stinging; when I isP<1mA, i.e. D>D4When the area is a safe area;
then, according to the calculation result, light alarm is carried out through an LED alarm lamp (104), and each area is projected through a projection lamp (106) for warning;
the amplifying circuit (205) is used for amplifying the audio signal transmitted by the central processing unit (202) and then carrying out sound alarm through the polyphonic loudspeaker (105).
2. The system for evaluating the personal safety of the single-phase broken line under the grounding fault via the tower as claimed in claim 1, wherein the power supply module (201) comprises a solar panel (107), a battery (203) and a power supply protection circuit (204);
the solar panel (107) and the power protection circuit (204) are respectively connected with the battery (203).
3. The system for evaluating the personal safety of the single-phase broken line under the grounding fault via the tower as claimed in claim 2, wherein the battery (203) is a rechargeable lithium battery.
4. The system for evaluating the personal safety of the single-phase broken line under the grounding fault via the tower as claimed in claim 1, wherein the projection lamp (106) projects each area in the form of a ring with different colors for warning.
5. The system for evaluating the personal safety of the single-phase broken line under the grounding fault via the tower as claimed in claim 1, further comprising a wireless transmission module (108);
the wireless transmission module (108) is connected with the central processing unit (202) and used for wirelessly uploading the fault information to the power department.
6. The system for evaluating the personal safety of the single-phase broken line under the tower earth fault according to claim 1, wherein the value c is calculated by the following algorithm:
(A) first stageInitialization: setting an evolution algebra counter G0Setting the maximum evolution algebra G to be 100, and randomly generating 50 different c values as an initial population P (0);
(B) individual evaluation: calculating the fitness f (c) of each individual in the population according to the formula;
Figure FDA0002390842380000031
wherein, V'PiIs a point PiCalculating the potential according to the existing theory;
(C) genetic operation: according to the fitness of each individual in the group, carrying out selection, crossing and mutation operations to generate a new generation of individuals;
(D) if G is0G is less than or equal to G, then G0＝G0+1, go to step (B); if G is0If the fitness is more than G, outputting the individual c with the maximum fitness obtained in the evolution process as the optimal solution, and stopping calculation.
7. The personal safety assessment method under the condition of the single-phase broken line passing through the tower earth fault is characterized by comprising the following steps:
(1) calculating any P of soil area around fault toweriPoint potential value VPi：
Setting the total circumference of the square grounding device II of the tower as L, dividing L into n micro-segments with the same size, and setting the length of the jth micro-segment as LjThus, any P in the soil area near the toweriPoint generated potential value VPiCalculated from the following formula:
Figure FDA0002390842380000032
① when PiWhen the point is located outside the area right above the square grounding device:
Figure FDA0002390842380000033
② when PiWhen the point is located in the area right above the square grounding device, the micro-segment j is divided into m micro-segments with equal size:
Figure FDA0002390842380000041
in the formulae (1) to (3), RPjIs a mutual resistance whose value is defined as the point P when the unit current source is applied to the jth micro-segmentiThe resulting potential; because the grounding device is not completely contacted with the soil closely, a contact layer formed by soil particles and air gaps exists, rho0Is the contact layer resistivity; h is0Is the contact layer thickness; i is the total current of the inlet font grounding device; rho is the soil resistivity; r and r' are points PiDistance r, r 'from the center point of the j-th micro-segment and its mirror image point'>>Lj(ii) a k denotes the kth micro-segment of micro-segment j, dj kIs the current flowing into the soil from the kth differential section of the differential section j; a is the conductor radius of the square grounding device, and b is the length of the kth differential segment; taking the geometric center of the square grounding device as the origin of coordinates, drawing an x coordinate axis along the extension of the transmission line to a front tower, drawing a y coordinate axis along the x coordinate axis by rotating 90 degrees anticlockwise, drawing a z coordinate axis perpendicular to the soil surface, and drawing x coordinate axis0、y0、z0Respectively the position coordinate, x, of the center point of the jth micro-segment1、y1、z1Are respectively PiThe position coordinates of the points; k0And K1A second class of modified Bessel functions of zero order and first order, respectively; λ is an integral variable; g is the number of calculation points, and c is a correction coefficient;
(2) via P (P) at an arbitrary distance of 1m1，q1，r1)、Q(p2，q2，r2) Calculating the current value I passing through the human body by the potential difference of the two pointsP：
Figure FDA0002390842380000042
Figure FDA0002390842380000043
In the formula (5), VP、VQP, Q for two points of potential; rinIs an internal resistance of the human body, R0Is the human skin resistance; b1Is the equivalent grounding radius of the human body;
in the formula (6), D is the maximum value of the horizontal distance from P, Q two points to the center of the square grounding device;
(3) dividing a step voltage dangerous area according to the bearable current of a human body:
when I isPWhen the current value is 100mA, D is calculated corresponding to P, Q two points1(ii) a All the same asPWhen D is 25mA, D is D2；IPWhen D is 6mA, D is D3；IPWhen 1mA, D is D4；
When I isP>100mA, i.e. D<D1When this area is at first-class risk, death results; when 25 is turned on<IP<100mA, i.e. D1<D<D2At the same time, the area is at second-class danger, which causes muscle contraction and dyspnea; when 6 is<IP<25mA, i.e. D2<D<D3At the time, the area is at risk of three, leading to intolerance of pain; when 1 is<IP<6mA, i.e. D3<D<D4At the time, the area is at risk of four, causing slight stinging; when I isP<1mA, i.e. D>D4When, this area is a safe area.
8. The method for evaluating the personal safety of the single-phase broken line under the tower earth fault according to claim 7, wherein the value c is calculated by the following algorithm:
(A) initialization: setting an evolution algebra counter G0Setting the maximum evolution algebra G to be 100, and randomly generating 50 different c values as an initial population P (0);
(B) individual evaluation: calculating the fitness f (c) of each individual in the population according to the formula;
Figure FDA0002390842380000051
wherein, V'PiIs a point PiCalculating the potential of the real sample;
(C) genetic operation: according to the fitness of each individual in the population, adopting MATLAB default selection, crossing and mutation operations to generate a new generation of individuals;
(D) if G is0G is less than or equal to G, then G0＝G0+1, go to step (B); if G is0If the fitness is more than G, outputting the individual c with the maximum fitness obtained in the evolution process as the optimal solution, and stopping calculation.
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* Cited by examiner, † Cited by third party
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US5764064A (en) * 1993-09-30 1998-06-09 Asea Brown Boveri Ab Method and device for identifying single ground faults
CN105119257A (en) * 2015-07-25 2015-12-02 李景禄 Dynamic processing method for single-phase transition resistor grounding fault of power distribution network
CN109375056A (en) * 2018-10-19 2019-02-22 国网浙江省电力有限公司电力科学研究院 Distribution broken string is grounded live test loop and fault simulation platform and test method
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