Bus low reactance protection method and system based on bus equivalent parameters

Abstract

The application discloses a bus low capacitance resistance protection method and system based on bus equivalent parameters, and comprises the following steps: acquiring three-phase voltage phasor values of a bus and three-phase current phasor values of each branch in the bus; determining three-phase bus differential currents based on the three-phase current phasor values of each branch in the bus; correcting the three-phase voltage phasor values of the bus to obtain three-phase voltage correction values; determining corresponding bus-to-ground capacitances of each phase based on the three-phase bus differential currents and the three-phase voltage correction values; and performing protection on any phase based on the corresponding bus-to-ground capacitance of the any phase and the three-phase bus differential current according to a preset protection criterion. The application identifies bus faults by the significant reduction of the bus-to-ground capacitance equivalent parameter when a fault occurs in the bus area. Since the bus-to-ground capacitance is a bus equivalent parameter, the system operation mode has no influence on the bus-to-ground capacitance, so that the protection reliability can be ensured, the sensitivity of the differential protection can be greatly improved, and the safe and stable operation level of the system is improved.

Description

Technical Field

[0001] This invention relates to the field of power system relay protection technology, and more specifically, to a method and system for low-capacitive reactance protection of busbars based on busbar equivalent parameters. Background Technology

[0002] Existing bus protection systems widely adopt bus current differential protection with ratio braking characteristics as the main protection. Bus current differential protection is based on Kirchhoff's current law, with the differential current being the fault current and the braking current being the sum of the current amplitudes of each branch of the bus. In the operation of a double busbar split, it has poor adaptability to the bus drain characteristics, which may lead to the bus differential protection failing to operate in severe cases.

[0003] With the large-scale integration of new energy sources into the new power system, the fault current exhibits amplitude limitations due to the influence of the control system strategy after a fault in the new energy power source. The fault characteristics on the new energy side are weakened, and the sensitivity of the current differential protection principle that identifies faults through fault current characteristics is greatly reduced, which seriously affects the operating performance of the current differential protection.

[0004] The aforementioned situation renders existing bus current differential protection inadequate, and may even lead to incorrect protection operation, failing to promptly isolate faults and thus affecting system stability. Currently, large-scale centralized renewable energy transmission grids have experienced multiple instances of decreased sensitivity in AC aggregation bus relay protection devices.

[0005] Therefore, a method for protecting low-capacitive reactance of busbars based on equivalent busbar parameters is needed. Summary of the Invention

[0006] This invention proposes a method and system for low-capacitive reactance protection of busbars based on busbar equivalent parameters, in order to solve the problem that existing busbar current differential protection is difficult to adapt to weak fault characteristics in large-scale renewable energy centralized transmission power grids, resulting in incorrect protection operation.

[0007] To address the aforementioned problems, according to one aspect of the present invention, a method for protecting low-capacitive reactance of a busbar based on equivalent busbar parameters is provided, the method comprising:

[0008] Obtain the three-phase voltage phasor values ​​of the busbar and the three-phase current phasor values ​​of each branch in the busbar;

[0009] The three-phase bus differential current is determined based on the three-phase current phasor values ​​of each branch in the bus.

[0010] Correct the phasor values ​​of the three-phase voltage of the busbar to obtain the corrected three-phase voltage values;

[0011] Based on the three-phase bus differential current and three-phase voltage correction values, determine the ground capacitive reactance of each corresponding bus;

[0012] For any phase, protection is provided based on the bus-to-ground capacitive reactance and three-phase bus differential current corresponding to that phase, according to a preset protection criterion.

[0013] Preferably, the method obtains the current phasor values ​​and voltage phasor values ​​in the following manner:

[0014]

[0015]

[0016]

[0017] in, Re(k) is the phasor value calculated by the sampling recursion algorithm; Re(k) is the real part of the phasor at the k-th point calculated by the sampling recursion algorithm, Im(k) is the imaginary part of the phasor at the k-th point calculated by the sampling recursion algorithm; x(k) is the value of the sampling value at the k-th point, x(kN) is the value of the sampling value at the kN-th point, and N is the number of sampling points per cycle of the power frequency quantity.

[0018] Preferably, the determination of the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus includes:

[0019]

[0020] in, for Differential current of the phase bus; For the nth branch Phase current phasor values:

[0021] Preferably, the correction of the three-phase voltage phasor values ​​of the busbar to obtain the three-phase voltage correction values ​​includes:

[0022]

[0023] in, for Phase voltage correction value; for Phase voltage phasor value; U N This is the system's rated voltage;

[0024] Preferably, determining the ground capacitive reactance of each corresponding busbar based on the three-phase busbar differential current and three-phase voltage correction values ​​includes:

[0025]

[0026] in, for Corresponding busbar to ground capacitance; for Differential current of the phase bus; for Phase voltage correction value;

[0027] Preferably, the protection for any phase based on the corresponding bus-to-ground capacitive reactance and three-phase bus differential current according to a preset protection criterion includes:

[0028] If satisfied and and If the duration meets the first preset time threshold, then the protection action exits;

[0029] If satisfied and and If the duration meets the second preset time threshold, then the protection action exits;

[0030] If satisfied and and Then protect the exit of the action;

[0031] in, for Corresponding busbar-to-ground capacitive reactance; Z set The preset busbar ground capacitance threshold; I set The preset current threshold is used; This is the sum of the differential currents of the three-phase busbars;

[0032] Preferably, the second preset time threshold is in, It is the sum of the differential currents of the three-phase busbars.

[0033] According to another aspect of the present invention, a busbar low-capacitive reactance protection system based on busbar equivalent parameters is provided, the system comprising:

[0034] The current and voltage phasor value acquisition unit is used to acquire the three-phase voltage phasor values ​​of the bus and the three-phase current phasor values ​​of each branch in the bus.

[0035] The bus differential current determination unit is used to determine the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus.

[0036] The phase voltage correction value acquisition unit is used to correct the three-phase voltage phasor values ​​of the bus and acquire the three-phase voltage correction values.

[0037] The bus-to-ground capacitive reactance determination unit is used to determine the corresponding bus-to-ground capacitive reactance based on the three-phase bus differential current and the three-phase voltage correction value.

[0038] The protection unit is used to protect any phase based on the corresponding bus-to-ground capacitive reactance and the three-phase bus differential current according to a preset protection criterion.

[0039] Preferably, the current and voltage phasor value acquisition unit acquires the current and voltage phasor values ​​in the following manner:

[0040]

[0041]

[0042]

[0043] in, Re(k) is the phasor value calculated by the sampling recursion algorithm; Re(k) is the real part of the phasor at the k-th point calculated by the sampling recursion algorithm, Im(k) is the imaginary part of the phasor at the k-th point calculated by the sampling recursion algorithm; x(k) is the value of the sampling value at the k-th point, x(kN) is the value of the sampling value at the kN-th point, and N is the number of sampling points per cycle of the power frequency quantity.

[0044] Preferably, the bus differential current determining unit determines the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus, including:

[0045]

[0046] in, for Differential current of the phase bus; For the nth branch Phase current phasor values;

[0047] Preferably, the phase voltage correction value acquisition unit corrects the three-phase voltage phasor values ​​of the bus to acquire the three-phase voltage correction values, including:

[0048]

[0049] in, for Phase voltage correction value; for Phase voltage phasor value; U N This is the system's rated voltage;

[0050] Preferably, the bus-to-ground capacitive reactance determining unit determines the corresponding bus-to-ground capacitive reactance based on the three-phase bus differential current and the three-phase voltage correction value, including:

[0051]

[0052] in, for Corresponding busbar to ground capacitance; for Differential current of the phase bus; for Phase voltage correction value;

[0053] Preferably, the protection unit, for any phase, performs protection based on the corresponding bus-to-ground capacitive reactance and three-phase bus differential current according to a preset protection criterion, including:

[0054] If satisfied and and If the duration meets the first preset time threshold, then the protection action exits;

[0055] If satisfied and and If the duration meets the second preset time threshold, then the protection action exits;

[0056] If satisfied and and Then protect the exit of the action;

[0057] in, for Corresponding busbar-to-ground capacitive reactance; Z set The preset busbar ground capacitance threshold; I set The preset current threshold is used; This is the sum of the differential currents of the three-phase busbars;

[0058] Preferably, the second preset time threshold is in, It is the sum of the differential currents of the three-phase busbars.

[0059] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the bus low-capacitive reactance protection methods based on bus equivalent parameters.

[0060] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0061] The aforementioned computer-readable storage medium; and

[0062] One or more processors for executing a program in the computer-readable storage medium.

[0063] This invention provides a method and system for low-capacitive reactance protection of busbars based on equivalent busbar parameters, comprising: acquiring the three-phase voltage phasor values ​​of the busbar and the three-phase current phasor values ​​of each branch in the busbar; determining the three-phase busbar differential current based on the three-phase current phasor values ​​of each branch in the busbar; correcting the three-phase voltage phasor values ​​of the busbar to obtain three-phase voltage correction values; determining the corresponding busbar-to-ground capacitive reactance based on the three-phase busbar differential current and the three-phase voltage correction values; and for any phase, performing protection according to a preset protection criterion based on the corresponding busbar-to-ground capacitive reactance and the three-phase busbar differential current. This invention identifies busbar faults by significantly reducing the equivalent parameters of the ground capacitive reactance during faults within the busbar area. Since the busbar-to-ground capacitive reactance is an equivalent busbar parameter, it is not affected by the system operating mode. This protection method can significantly improve the sensitivity of differential protection while ensuring protection reliability and improving the safe and stable operation level of the system. Attached Figure Description

[0064] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0065] Figure 1 A flowchart of a busbar low-capacitive reactance protection method 100 based on busbar equivalent parameters according to an embodiment of the present invention;

[0066] Figure 2 This is a logic diagram of the busbar ground capacitance protection operation according to an embodiment of the present invention;

[0067] Figure 3 This is a diagram of a dual-busbar dual-branch system according to an embodiment of the present invention;

[0068] Figure 4 (a), (b) and (c) are respectively diagrams showing the operation results of the differential protection of bus I when a single-phase metallic grounding fault occurs in the AN phase of bus I in accordance with the embodiments of the present invention.

[0069] Figure 5 (a), (b), and (c) are respectively diagrams showing the operation results of the differential protection of bus II when a single-phase metallic ground fault occurs in the AN phase of bus I in accordance with the embodiments of the present invention.

[0070] Figure 6 (a), (b) and (c) are respectively diagrams showing the operation results of the bus differential protection during a single-phase metallic grounding fault in the I bus occurrence zone according to an embodiment of the present invention.

[0071] Figure 7 (a), (b), and (c) are respectively diagrams showing the operation results of the differential protection of bus I when CN in the bus I generation zone fails through a 60Ω transition resistor according to an embodiment of the present invention;

[0072] Figure 8 (a), (b), and (c) are respectively the operation results of the differential protection of bus II when CN in the bus I fault occurs through a 60Ω transition resistor according to an embodiment of the present invention;

[0073] Figure 9 (a), (b), and (c) are respectively diagrams showing the operation results of the bus differential protection when CN in the I bus fault zone is faulted by a 60Ω transition resistor according to an embodiment of the present invention.

[0074] Figure 10 This is a schematic diagram of the structure of a busbar low-capacitance protection system 1000 based on busbar equivalent parameters according to an embodiment of the present invention. Detailed Implementation

[0075] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0076] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0077] Figure 1 This is a flowchart of a busbar low-capacitive reactance protection method 100 based on busbar equivalent parameters according to an embodiment of the present invention. Figure 1 As shown, the busbar low-capacitive reactance protection method based on busbar equivalent parameters provided by this embodiment of the invention identifies busbar faults by the significant reduction in the equivalent parameters of the busbar-to-ground capacitive reactance during a fault within the busbar area. Since the busbar-to-ground capacitive reactance is a busbar equivalent parameter, it is not affected by the system operating mode. This protection method can significantly improve the sensitivity of differential protection while ensuring protection reliability and improving the safe and stable operation level of the system. The busbar low-capacitive reactance protection method 100 based on busbar equivalent parameters provided by this embodiment of the invention starts from step 101, in which the three-phase voltage phasor values ​​of the busbar and the three-phase current phasor values ​​of each branch in the busbar are obtained.

[0078] Preferably, the method obtains the current phasor values ​​and voltage phasor values ​​in the following manner:

[0079]

[0080]

[0081]

[0082] in, Re(k) is the phasor value calculated by the sampling recursion algorithm; Re(k) is the real part of the phasor at the k-th point calculated by the sampling recursion algorithm, Im(k) is the imaginary part of the phasor at the k-th point calculated by the sampling recursion algorithm; x(k) is the value of the sampling value at the k-th point, x(kN) is the value of the sampling value at the kN-th point, and N is the number of sampling points per cycle of the power frequency quantity.

[0083] In this invention, a sampled value recursive algorithm is used to calculate the voltage phasor values ​​and the current phasor values. The sampled value recursive algorithm is as follows:

[0084]

[0085]

[0086]

[0087] In the formula: x(k) is the value of the k-th sample point, x(kN) is the value of the kN-th sample point, N is the number of sampling points per cycle of the power frequency quantity, Re(k) is the real part of the phasor at the k-th point calculated by the sample value recursive algorithm, and Im(k) is the imaginary part of the phasor at the k-th point calculated by the sample value recursive algorithm. The phasor value is calculated by the sampling value recursion algorithm.

[0088] In this invention, the bus three-phase voltage sampling value is u a (k), u b (k), u c (k), the phasor value calculated using the Fourier recursive algorithm of sampled values ​​is The three-phase current sampling value of each branch of the busbar is i an (k), i bn (k), i cn (k), the phasor value calculated using the Fourier recursive algorithm of sampled values ​​is n represents the nth busbar.

[0089] In step 102, the three-phase bus differential current is determined based on the three-phase current phasor values ​​of each branch in the bus.

[0090] Preferably, the determination of the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus includes:

[0091]

[0092] in, for Differential current of the phase bus; For the nth branch Phase current phasor values;

[0093] In this invention, the bus differential current is calculated using the current phasor values ​​of each branch of the bus.

[0094]

[0095] In the formula: These are the currents of each branch of the busbar; For Differential current of the phase bus;

[0096] In step 103, the three-phase voltage phasor values ​​of the busbar are corrected to obtain the three-phase voltage correction values.

[0097] Preferably, the correction of the three-phase voltage phasor values ​​of the busbar to obtain the three-phase voltage correction values ​​includes:

[0098]

[0099] in, for Phase voltage correction value; for Phase voltage phasor value; U N This is the system's rated voltage;

[0100] In this invention, to prevent the protection from maloperating due to excessively low fault voltage outside the protection zone, the voltage phasor amplitude is corrected. The correction method involves increasing the voltage phasor amplitude proportionally without changing the phase of the voltage phasor, including:

[0101]

[0102] In the formula: U N This is the system's rated voltage; for Phase voltage correction value;

[0103] In step 104, based on the three-phase bus differential current and the three-phase voltage correction value, the capacitive reactance to ground of each corresponding bus is determined.

[0104] Preferably, determining the ground capacitive reactance of each corresponding busbar based on the three-phase busbar differential current and three-phase voltage correction values ​​includes:

[0105]

[0106] in, for Corresponding busbar to ground capacitance; for Differential current of the phase bus; for Phase voltage correction value;

[0107] In this invention, the modified bus voltage phasor is utilized. Differential current phasor with bus The ratio of the busbar to the ground capacitive reactance is calculated.

[0108]

[0109] in, for Corresponding busbar to ground capacitance; for Differential current of the phase bus; for Phase voltage correction value.

[0110] In step 105, for any phase, protection is performed based on the bus-to-ground capacitive reactance and three-phase bus differential current of that corresponding phase according to a preset protection criterion.

[0111] Preferably, the protection for any phase based on the corresponding bus-to-ground capacitive reactance and three-phase bus differential current according to a preset protection criterion includes:

[0112] If satisfied and and If the duration meets the first preset time threshold, then the protection action exits;

[0113] If satisfied and and If the duration meets the second preset time threshold, then the protection action exits;

[0114] If satisfied and and Then protect the exit of the action;

[0115] in, for Corresponding busbar-to-ground capacitive reactance; Z set The preset busbar ground capacitance threshold; I set The preset current threshold is used; This is the sum of the differential currents of the three-phase busbars;

[0116] Preferably, the second preset time threshold is in, It is the sum of the differential currents of the three-phase busbars.

[0117] In this invention, the busbar-to-ground capacitive reactance is... Construct a criterion for low-capacitive reactance protection of busbars, when the amplitude of the busbar-to-ground capacitive reactance... Less than the low capacitance protection setting value Z of the busbar set At that time, the busbar low capacitance protection criterion meets the following conditions:

[0118] Bus differential current Construct a criterion for high-sensitivity differential protection of the busbar, when the amplitude of the busbar differential current... Greater than the busbar high-sensitivity differential current setting I set At that time, the criteria for high-sensitivity differential protection of the busbar meet the following conditions:

[0119] To prevent maloperation of the protection system during transient faults outside the protection zone, inverse time-limit logic is used to determine the continuous acknowledgment time of the protection system. When the protection condition is met for 10 consecutive ms, the action exits; when At the same time, protect continuous The exit condition is met; when At this time, the protection does not require continuous confirmation; if the conditions are met, the exit will activate instantaneously. Among these,

[0120]

[0121] in, for Corresponding busbar-to-ground capacitive reactance; Z set The preset busbar ground capacitance threshold; I set The preset current threshold is used; This is the sum of the differential currents of the three-phase busbars; It is the sum of the differential currents of the three-phase busbars.

[0122] like Figure 2 As shown, when the busbar low capacitance protection criterion meets the condition, and at the same time, the busbar high sensitivity current differential protection criterion meets the condition, the busbar low capacitance protection will take action and output the output after being confirmed by the inverse time-limited logic for t consecutive times.

[0123] This invention patent addresses the problem that existing bus current differential protection is unable to adapt to weak fault characteristics in large-scale renewable energy centralized transmission power grids, leading to incorrect protection operation. It innovatively proposes a low-capacitive reactance protection method for bus based on bus equivalent parameters, which can significantly improve the sensitivity of differential protection while ensuring protection reliability and improving the safe and stable operation level of the system.

[0124] In this invention, the method is illustrated using the following scenario as an example.

[0125] 1) Fault within the 220kV double busbar and double branch busbar zone

[0126] The busbar system diagram for a 220kV double busbar double branch connection is as follows: Figure 3 As shown in the figure, the double busbars I and II are symmetrical to the double busbars III and IV. Each busbar section is equipped with 3 busbar branches. In actual operation, the number of busbar branches can be any value without affecting the protection criterion form and operation performance. The fault is set on busbar I.

[0127] When a single-phase metallic ground fault (AN) occurs in the AN section of a 220kV double busbar double-busbar I busbar, the simulation results of the I busbar differential are as follows: Figure 4 As shown in (a), (b), and (c), the low capacitive reactance value of phase A busbar is less than the set value within 0.83ms. The busbar differential current is 25kA, and it enters the operating region at 1.67ms. Based on the overall operating logic of the low capacitive reactance protection, the low capacitive reactance protection operates at 2.5ms. The protections for phases B and C do not operate.

[0128] The simulation results of the mother-son difference are as follows: Figure 5 As shown in (a), (b) and (c), the protection for phases A, B and C does not activate.

[0129] Simulation results of large bus differential are as follows Figure 6 As shown in (a), (b), and (c), the low capacitive reactance value of phase A busbar is less than the set value within 0.83ms. The busbar differential current is 25kA, and it enters the operating region at 1.67ms. Based on the overall operating logic of the low capacitive reactance protection, the low capacitive reactance protection operates at 2.5ms. The protections for phases B and C do not operate.

[0130] (2) 220kV double busbar double busbar connected to an external fault via a high transition resistance zone

[0131] When a fault occurs in the CN section of the 220kV double busbar double busbar I busbar fault zone via a 60Ω transition resistor, the simulation results of the I busbar small differential are as follows: Figure 7 As shown in (a), (b), and (c), the low capacitive reactance value of phase A busbar is less than the set value in 1.67ms. The busbar differential current is 2kA, and it enters the operating region in 6.67ms. Based on the overall low capacitive reactance protection operating logic, the low capacitive reactance protection of busbar operates in 10.83ms. The protections for phases B and C do not operate.

[0132] The simulation results of the mother-son difference are as follows: Figure 8 As shown in (a), (b) and (c), the protection for phases A, B and C does not activate.

[0133] Simulation results of large bus differential are as follows Figure 9 As shown in (a), (b), and (c), the low capacitive reactance value of phase A busbar is less than the set value in 1.67ms. The busbar differential current is 2kA, and it enters the operating region in 6.67ms. Based on the overall low capacitive reactance protection operating logic, the low capacitive reactance protection of busbar operates in 10.83ms. The protections for phases B and C do not operate.

[0134] Figure 10 This is a schematic diagram of the structure of a busbar low-capacitive reactance protection system 1000 based on busbar equivalent parameters according to an embodiment of the present invention. Figure 10 As shown, the busbar low capacitance protection system 1000 based on busbar equivalent parameters provided in this embodiment of the invention includes: a current and voltage phasor value acquisition unit 1001, a busbar differential current determination unit 1002, a phase voltage correction value acquisition unit 1003, a busbar-to-ground capacitance determination unit 1004, and a protection unit 1005.

[0135] Preferably, the current and voltage phasor value acquisition unit 1001 is used to acquire the three-phase voltage phasor value of the bus and the three-phase current phasor value of each branch in the bus.

[0136] Preferably, the current and voltage phasor value acquisition unit 1001 acquires the current and voltage phasor values ​​in the following manner:

[0137]

[0138]

[0139]

[0140] in, Re(k) is the phasor value calculated by the sampling recursion algorithm; Re(k) is the real part of the phasor at the k-th point calculated by the sampling recursion algorithm, Im(k) is the imaginary part of the phasor at the k-th point calculated by the sampling recursion algorithm; x(k) is the value of the sampling value at the k-th point, x(kN) is the value of the sampling value at the kN-th point, and N is the number of sampling points per cycle of the power frequency quantity.

[0141] Preferably, the bus differential current determination unit 1002 is used to determine the three-phase bus differential current based on the three-phase current phasor value of each branch in the bus.

[0142] Preferably, the bus differential current determining unit 1002 determines the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus, including:

[0143]

[0144] in, for Differential current of the phase bus; For the nth branch Phase current phasor values;

[0145]

[0146] Preferably, the phase voltage correction value acquisition unit 1003 is used to correct the three-phase voltage phasor values ​​of the busbar and acquire the three-phase voltage correction value.

[0147] Preferably, the phase voltage correction value acquisition unit 1003 corrects the three-phase voltage phasor values ​​of the busbar to acquire the three-phase voltage correction values, including:

[0148]

[0149] in, for Phase voltage correction value; for Phase voltage phasor value; U N This is the system's rated voltage;

[0150] Preferably, the bus-to-ground capacitive reactance determination unit 1004 is used to determine the corresponding bus-to-ground capacitive reactance based on the three-phase bus differential current and the three-phase voltage correction value.

[0151] Preferably, the bus-to-ground capacitive reactance determining unit 1004 determines the corresponding bus-to-ground capacitive reactance based on the three-phase bus differential current and the three-phase voltage correction value, including:

[0152]

[0153] in, for Corresponding busbar to ground capacitance; for Differential current of the phase bus; for Phase voltage correction value;

[0154] Preferably, the protection unit 1005 is used to protect any phase based on the corresponding bus-to-ground capacitive reactance and the three-phase bus differential current according to a preset protection criterion.

[0155] Preferably, the protection unit 1005, for any phase, performs protection based on the corresponding bus-to-ground capacitive reactance and three-phase bus differential current according to a preset protection criterion, including:

[0156] If satisfied and and If the duration meets the first preset time threshold, then the protection action exits;

[0157] If satisfied and and If the duration meets the second preset time threshold, then the protection action exits;

[0158] If satisfied and and Then protect the exit of the action;

[0159] in, for Corresponding busbar-to-ground capacitive reactance; Z set The preset busbar ground capacitance threshold; I set The preset current threshold is used; This is the sum of the differential currents of the three-phase busbars;

[0160] Preferably, the second preset time threshold is in, It is the sum of the differential currents of the three-phase busbars.

[0161] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the bus low-capacitive reactance protection methods based on bus equivalent parameters.

[0162] The busbar low-capacitive reactance protection system 1000 based on busbar equivalent parameters in one embodiment of the present invention corresponds to the busbar low-capacitive reactance protection method 100 based on busbar equivalent parameters in another embodiment of the present invention, and will not be described again here.

[0163] According to another aspect of the present invention, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the bus low-capacitive reactance protection methods based on bus equivalent parameters.

[0164] According to another aspect of the present invention, the present invention provides an electronic device, comprising:

[0165] The aforementioned computer-readable storage medium; and

[0166] One or more processors for executing a program in the computer-readable storage medium.

[0167] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

[0168] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the art, unless otherwise expressly defined herein. All references to “a / the / the [device, component, etc.]” ​​are openly interpreted as at least one instance of said device, component, etc., unless otherwise expressly stated. The steps of any method disclosed herein need not be performed in the exact order disclosed unless explicitly stated otherwise.

[0169] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0170] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0171] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0172] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for protecting low-capacitive reactance of busbars based on equivalent busbar parameters, characterized in that, The method includes: Obtain the three-phase voltage phasor values ​​of the busbar and the three-phase current phasor values ​​of each branch in the busbar; The three-phase bus differential current is determined based on the three-phase current phasor values ​​of each branch in the bus. Correct the phasor values ​​of the three-phase voltage of the busbar to obtain the corrected three-phase voltage values; Based on the three-phase bus differential current and three-phase voltage correction values, determine the ground capacitive reactance of each corresponding bus; For any phase, protection is provided based on the bus-to-ground capacitive reactance and three-phase bus differential current corresponding to that phase, according to the preset protection criteria. The step of correcting the three-phase voltage phasor values ​​of the busbar to obtain the three-phase voltage correction values ​​includes: ， in, for Phase voltage correction value; for Phase voltage phasor value; This is the system's rated voltage; ; The step of determining the ground capacitive reactance of each corresponding busbar based on the three-phase busbar differential current and three-phase voltage correction values ​​includes: ， in, for Differential current of the phase bus; for Phase voltage correction value; Wherein, for any phase, protection is performed based on the corresponding bus-to-ground capacitive reactance and three-phase bus differential current according to a preset protection criterion, including: If satisfied ,and ,and If the duration meets the first preset time threshold, then the protection action exits; If satisfied ,and ,and If the duration meets the second preset time threshold, then the protection action exits; If satisfied ,and ,and Then protect the exit of the action; in, The preset busbar ground capacitance threshold is used; The preset current threshold is used; It is the sum of the differential currents of the three-phase busbars.

2. The method according to claim 1, characterized in that, The method obtains current phasor values ​​and voltage phasor values ​​in the following manner: ， ， ， in, The phasor value is calculated using the sample value recursion algorithm; The real part of the phasor at point k is calculated using the sampled value recursion algorithm. The imaginary part of the phasor at point k is calculated using the sampled value recursion algorithm; This represents the value at the k-th sample point. This represents the value at the kNth sampling point, where N is the number of sampling points per cycle for the power frequency quantity.

3. The method according to claim 1, characterized in that, The determination of the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus includes: ， in, for Differential current of the phase bus; For the nth branch Phase current phasor values; .

4. The method according to claim 1, characterized in that, The second preset time threshold is ;in, It is the sum of the differential currents of the three-phase busbars.

5. A busbar low-capacitive reactance protection system based on busbar equivalent parameters, characterized in that, The system includes: The current and voltage phasor value acquisition unit is used to acquire the three-phase voltage phasor values ​​of the bus and the three-phase current phasor values ​​of each branch in the bus. The bus differential current determination unit is used to determine the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus. The phase voltage correction value acquisition unit is used to correct the three-phase voltage phasor values ​​of the bus and acquire the three-phase voltage correction values. The bus-to-ground capacitive reactance determination unit is used to determine the corresponding bus-to-ground capacitive reactance based on the three-phase bus differential current and the three-phase voltage correction value. The protection unit is used to protect any phase based on the corresponding bus-to-ground capacitive reactance and three-phase bus differential current according to a preset protection criterion. The phase voltage correction value acquisition unit corrects the three-phase voltage phasor values ​​of the busbar and acquires the three-phase voltage correction values, including: ， in, for Phase voltage correction value; for Phase voltage phasor value; This is the system's rated voltage; ; The bus-to-ground capacitive reactance determination unit determines the corresponding bus-to-ground capacitive reactance based on the three-phase bus differential current and the three-phase voltage correction value, including: ， in, for Differential current of the phase bus; for Phase voltage correction value; The protection unit, for any phase, performs protection based on the corresponding bus-to-ground capacitive reactance and three-phase bus differential current according to a preset protection criterion, including: If satisfied ,and ,and If the duration meets the first preset time threshold, then the protection action exits; If satisfied ,and ,and If the duration meets the second preset time threshold, then the protection action exits; If satisfied ,and ,and Then protect the exit of the action; in, The preset busbar ground capacitance threshold is used; The preset current threshold is used; It is the sum of the differential currents of the three-phase busbars.

6. The system according to claim 5, characterized in that, The current and voltage phasor value acquisition unit acquires current and voltage phasor values ​​in the following manner: ， ， ， in, The phasor value is calculated using the sample value recursion algorithm; The real part of the phasor at point k is calculated using the sampled value recursion algorithm. The imaginary part of the phasor at point k is calculated using the sampled value recursion algorithm; This represents the value at the k-th sample point. This represents the value at the kNth sampling point, where N is the number of sampling points per cycle for the power frequency quantity.

7. The system according to claim 5, characterized in that, The bus differential current determination unit determines the three-phase bus differential current based on the three-phase current phasor values ​​of each branch in the bus, including: ， in, for Differential current of the phase bus; For the nth branch Phase current phasor values; .

8. The system according to claim 5, characterized in that, The second preset time threshold is ;in, It is the sum of the differential currents of the three-phase busbars.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the system as described in any one of claims 1-4.

10. An electronic device, characterized in that, include: The computer-readable storage medium as described in claim 9; as well as One or more processors for executing a program in the computer-readable storage medium.

Images