CN113641205B - Method and device for processing three-phase-to-ground voltage - Google Patents
Method and device for processing three-phase-to-ground voltage Download PDFInfo
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- CN113641205B CN113641205B CN202110951464.0A CN202110951464A CN113641205B CN 113641205 B CN113641205 B CN 113641205B CN 202110951464 A CN202110951464 A CN 202110951464A CN 113641205 B CN113641205 B CN 113641205B
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Abstract
The invention discloses a method and a device for processing three-phase voltage to earth. Wherein, the method comprises the following steps: acquiring characteristic data of the power distribution network; determining a voltage vector diagram of the power distribution network according to the characteristic data; and determining the three-phase voltage to ground after single-phase grounding according to a voltage vector diagram of the power distribution network. The invention solves the technical problem that the steady-state voltage of the ungrounded neutral point power distribution system cannot be accurately and clearly expressed in the related technology.
Description
Technical Field
The invention relates to the field of electric power, in particular to a method and a device for processing three-phase voltage to earth.
Background
The distribution network single-phase earth fault accounts for nearly one third of the total distribution network faults, so that the analysis of the single-phase earth fault characteristics, particularly the steady-state characteristics of the voltage of the distribution network after single-phase earth is analyzed, and the analysis has important significance on the development of a distribution network earth fault processing theory and the guidance of engineering practice.
At present, in domestic and foreign documents, particularly, system representation methods for steady-state voltage of a neutral point ungrounded distribution system are based on a phasor mode, but specific representation methods are different from person to person, and generally have the problems of non-intuition and difficulty in understanding physical significance, so that engineering technicians are difficult to understand ideas to be expressed by authors (or designers) at the first time, and therefore the practicability is poor.
Aiming at the problem that the steady-state voltage of the neutral point ungrounded power distribution system cannot be accurately and clearly expressed in the related technology, an effective solution is not provided at present.
Disclosure of Invention
The embodiment of the invention provides a method and a device for processing three-phase voltage to ground, which are used for at least solving the technical problem that the steady-state voltage of a neutral point ungrounded power distribution system cannot be accurately and clearly expressed in the related technology.
According to an aspect of the embodiments of the present invention, there is provided a method for processing a three-phase voltage to ground, including: acquiring characteristic data of the power distribution network; determining a voltage vector diagram of the power distribution network according to the characteristic data; and determining the three-phase voltage to ground after single-phase grounding according to the voltage vector diagram of the power distribution network.
Optionally, the obtaining characteristic data of the power distribution network includes: acquiring characteristic parameters of the power distribution network in a steady-state process with fault operation, wherein the characteristic parameters comprise at least one of the following parameters: ground current, power supply electromotive force, ground resistance, line-to-ground total capacitance, faulty phase voltage, and neutral voltage.
Optionally, the determining the three-phase voltage to ground after the single-phase grounding according to the voltage vector diagram of the power distribution network includes: processing the voltage vector diagram of the power distribution network by using a double circle method to obtain the first phase-to-ground voltage, the second phase-to-ground voltage and the third phase-to-ground voltage; and setting a predetermined auxiliary line on a voltage vector diagram of the power distribution network, and determining the relative magnitude among the first phase voltage to ground, the second phase voltage to ground and the third phase voltage to ground.
Optionally, setting a predetermined auxiliary line on a voltage vector diagram of the power distribution network, determining a relative magnitude between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage, includes: when the first phase is brought to single-phase metallic ground, the first phase-to-ground voltage will drop to zero; the magnitude of the neutral point potential will rise to a phase voltage in the opposite direction to the supply voltage of the first phase; the second phase-to-ground voltage and the third phase-to-ground voltage are raised to line voltages.
Optionally, setting a predetermined auxiliary line on a voltage vector diagram of the power distribution network, determining a relative magnitude between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage, includes: when the first phase grounding fault disappears or normally operates, the first phase grounding voltage is changed into a normal operation voltage; the neutral point potential returns to zero; the second phase-to-ground voltage and the third phase-to-ground voltage are restored to phase voltages.
Optionally, setting a predetermined auxiliary line on a voltage vector diagram of the power distribution network, determining a relative magnitude between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage, includes: when resistive grounding occurs, the first phase-to-ground voltage is greater than zero and less than a first phase power supply electromotive force; the neutral point potential is greater than zero and less than the first phase power supply electromotive force; the second phase ground voltage is the sum of neutral point voltage and second phase power supply electromotive force, and the third phase ground voltage is the sum of neutral point voltage and third phase power supply electromotive force.
According to another aspect of the embodiments of the present invention, there is also provided a processing apparatus for a three-phase voltage to ground, including: the acquisition module is used for acquiring characteristic data of the power distribution network; the first determining module is used for determining a voltage vector diagram of the power distribution network according to the characteristic data; and the second determination module is used for determining the three-phase voltage to ground after single-phase grounding according to the voltage vector diagram of the power distribution network.
Optionally, the obtaining module includes: the acquiring unit is used for acquiring characteristic parameters of the power distribution network in a steady-state process with fault operation, wherein the characteristic parameters comprise at least one of the following parameters: ground current, power supply electromotive force, ground resistance, line-to-ground total capacitance, faulty phase voltage, and neutral voltage.
According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium, where the computer-readable storage medium includes a stored program, and when the program runs, the apparatus where the computer-readable storage medium is located is controlled to execute the processing method of the three-phase voltage to ground voltage described in any one of the above.
According to another aspect of the embodiments of the present invention, there is also provided a processor, where the processor is configured to execute a program, where the program executes a processing method of any one of the above three-phase voltage to ground voltages.
In the embodiment of the invention, the characteristic data of the power distribution network is acquired; determining a voltage vector diagram of the power distribution network according to the characteristic data; the method comprises the steps of determining the three-phase voltage to ground after single-phase grounding according to a voltage vector diagram of the power distribution network, determining a corresponding voltage vector diagram according to characteristic data of the power distribution network, and obtaining the three-phase voltage to ground after single-phase grounding by using the voltage vector diagram, so that the purpose of obtaining the steady-state voltage with clear concepts and clear conclusions is achieved, the steady-state voltage of the neutral point ungrounded power distribution system is accurately and clearly expressed, the technical effect of strong practicability is achieved, and the technical problem that the steady-state voltage of the neutral point ungrounded power distribution system cannot be accurately and clearly expressed in the related technology is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention and do not constitute a limitation of the invention. In the drawings:
FIG. 1 is a flow diagram of a method of processing three-phase voltage-to-ground in accordance with an embodiment of the invention;
FIG. 2 is a schematic diagram of a simplified electrical circuit for a neutral ungrounded grid according to an alternative embodiment of the present invention;
FIG. 3 is a Thevenin equivalent circuit diagram according to an alternative embodiment of the invention;
FIG. 4 is a steady state voltage vector diagram for a neutral ungrounded system in accordance with an alternative embodiment of the present invention;
fig. 5 is a schematic diagram of a processing apparatus of three-phase voltage to ground according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Moreover, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1
In accordance with an embodiment of the present invention, there is provided an embodiment of a method for processing three-phase voltage to ground, it should be noted that the steps illustrated in the flowchart of the drawings may be performed in a computer system such as a set of computer executable instructions, and that although a logical order is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in an order different than here.
Fig. 1 is a flowchart of a method for processing three-phase voltage to ground according to an embodiment of the present invention, as shown in fig. 1, the method including the steps of:
step S102, acquiring characteristic data of the power distribution network;
in an optional implementation, the obtaining characteristic data of the power distribution network includes: acquiring characteristic parameters of the power distribution network in a steady state process of operation with faults, wherein the characteristic parameters comprise at least one of the following parameters: ground current, power supply electromotive force, ground resistance, line-to-ground total capacitance, faulty phase voltage, and neutral voltage.
Step S104, determining a voltage vector diagram of the power distribution network according to the characteristic data;
and S106, determining the three-phase voltage to earth after single-phase grounding according to the voltage vector diagram of the power distribution network.
In an optional embodiment, the three-phase voltage to ground includes a first voltage to ground, a second voltage to ground, and a third voltage to ground, and the three-phase voltage to ground after the single-phase ground is determined according to a voltage vector diagram of the power distribution network, including: processing a voltage vector diagram of the power distribution network by using a double-circle method to obtain a first phase-to-ground voltage, a second phase-to-ground voltage and a third phase-to-ground voltage; a predetermined auxiliary line is set on a voltage vector diagram of a distribution network, and a magnitude of a phase-to-ground voltage among a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage is determined.
In an alternative embodiment, setting a predetermined auxiliary line on a voltage vector diagram of a distribution network, determining a magnitude of a phase-to-ground voltage between a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage, includes: when the first phase is brought to single-phase metallic grounding, the first phase-to-ground voltage will drop to zero; the magnitude of the neutral point potential will rise to a phase voltage in the opposite direction to the supply voltage of the first phase; the second phase voltage to ground and the third phase voltage to ground are raised to line voltages.
In an alternative embodiment, setting a predetermined auxiliary line on a voltage vector diagram of a power distribution network, determining a relative magnitude between a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage, includes: when the first phase grounding fault disappears or the first phase grounding fault normally runs, the first phase grounding voltage is changed into a normal running voltage; the neutral point potential returns to zero; the second phase voltage to ground and the third phase voltage to ground are restored to phase voltages.
In an alternative embodiment, setting a predetermined auxiliary line on a voltage vector diagram of a power distribution network, determining a relative magnitude between a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage, includes: when resistive grounding occurs, the first phase-to-ground voltage is greater than zero and less than the first phase power supply electromotive force; the neutral point potential is greater than zero and less than the first phase power supply electromotive force; the second phase-to-ground voltage is the sum of the neutral point voltage and the second phase power supply electromotive force, and the third phase-to-ground voltage is the sum of the neutral point voltage and the third phase power supply electromotive force.
Through the steps, the characteristic data of the power distribution network can be acquired; determining a voltage vector diagram of the power distribution network according to the characteristic data; the method comprises the steps of determining the three-phase earth voltage after single-phase grounding according to a voltage vector diagram of the power distribution network, determining a corresponding voltage vector diagram according to characteristic data of the power distribution network, and obtaining the three-phase earth voltage after single-phase grounding by using the voltage vector diagram, so that the purpose of obtaining the steady-state voltage with clear and understandable concepts and definite conclusion is achieved, the steady-state voltage of the neutral point ungrounded power distribution system is accurately and clearly expressed, the technical effect of strong practicability is achieved, and the technical problem that the steady-state voltage of the neutral point ungrounded power distribution system cannot be accurately and clearly expressed in the related technology is solved.
In an optional embodiment, the three-phase voltage to ground includes a first voltage to ground, a second voltage to ground, and a third voltage to ground, and the three-phase voltage to ground after the single-phase grounding is determined according to a voltage vector diagram of a power distribution network, including: processing a voltage vector diagram of the power distribution network by using a double-circle method to obtain a first phase-to-ground voltage, a second phase-to-ground voltage and a third phase-to-ground voltage; a predetermined auxiliary line is set on a voltage vector diagram of a distribution network, and a magnitude of a phase-to-ground voltage among a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage is determined.
In an alternative embodiment, setting a predetermined auxiliary line on a voltage vector diagram of a distribution network, determining a magnitude of a phase-to-ground voltage between a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage, includes: when the first phase is brought to single-phase metallic ground, the first phase-to-ground voltage will drop to zero; the magnitude of the neutral point potential will rise to a phase voltage in the opposite direction to the supply voltage of the first phase; the second phase voltage to ground and the third phase voltage to ground are raised to line voltages.
In an alternative embodiment, setting a predetermined auxiliary line on a voltage vector diagram of a power distribution network, determining a relative magnitude between a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage, includes: when the first phase ground fault disappears or the first phase ground fault normally operates, the first phase ground voltage becomes a normal operation voltage; the neutral point potential returns to zero; the second phase voltage to ground and the third phase voltage to ground are restored to phase voltages.
In an alternative embodiment, setting a predetermined auxiliary line on a voltage vector diagram of a distribution network, determining a magnitude of a phase-to-ground voltage between a first phase-to-ground voltage, a second phase-to-ground voltage, and a third phase-to-ground voltage, includes: when resistive grounding occurs, the first phase-to-ground voltage is greater than zero and less than the first phase power supply electromotive force; the neutral point potential is greater than zero and less than the first phase power supply electromotive force; the second phase-to-ground voltage is the sum of the neutral point voltage and the second phase power supply electromotive force, and the third phase-to-ground voltage is the sum of the neutral point voltage and the third phase power supply electromotive force.
An alternative embodiment of the invention is described in detail below.
In an alternative embodiment, the method for representing the steady-state voltage of the distribution system with the ungrounded neutral point can be utilized, and the method utilizes thevenin equivalent circuit and basic geometric knowledge to clearly obtain the three-phase voltage to ground after single-phase grounding
And
can be analyzed in detail by adding auxiliary lines
And
the relative size therebetween. In addition, by analyzing the steady-state voltage characteristics of the power distribution network during single-phase earth faults, the concept is clear and easy to understand, the conclusion is clear, the method is particularly suitable for being used as an auxiliary decision-making means for power distribution network fault analysis, and the practicability is very good.
After a single-phase earth fault occurs in a system with no earth at a neutral point, the system usually goes through a transient transition process and then enters a steady-state process with fault operation. FIG. 2 is a simplified circuit diagram of a neutral ungrounded power grid according to an alternative embodiment of the present invention, where three lines are provided on a bus, and the capacitances of the three lines with respect to ground are C 01 、C 02 And C 03 The following assumptions were made during the analysis: (1) the electromotive force of the three-phase power supply is symmetrical. Namely, it is
And
symmetry; (2) three phases are equal to ground capacitance. Because the distance of the distribution line is short, the three-phase-to-ground capacitance difference is not large. It should be noted that two capacitors exist on the distribution line, the first is the line interphase capacitor, the second is the line-to-ground capacitor, and obviously what is related to the single-phase ground fault is the line-to-ground capacitor; (3) the line uses centralized parameters. Because the length of the power distribution network line is generally short, centralized parameters can be adopted; (4) since the capacitive reactance of the equivalent circuit is much larger than the impedance when the single phase is grounded, the impedance of the line can be ignored during the analysis of the steady state process.
When analyzing the characteristics of the single-phase earth fault, two methods, namely thevenin theorem and a symmetric component method, can be generally adopted. It is generally simpler to use thevenin's theorem when analyzing voltage characteristics, and more intuitive to use a symmetric component method when analyzing current characteristics. As shown in fig. 2, when a single-phase earth fault occurs in the a-phase, analysis is performed by using thevenin's theorem, and the resistance branch between the earth point and the ground is regarded as an external circuit. Thevenin equivalent voltage should be externalThe voltage when the circuit is open is obviously equal to the electromotive force of the A-phase power supply. Thevenin equivalent impedance is the internal impedance of the system, and since the line-to-ground capacitive reactance is much larger than the line resistance and reactance, the Thevenin equivalent impedance is approximately equal to the system-to-ground capacitive reactance, so as to obtain a Thevenin equivalent circuit, FIG. 3 is a Thevenin equivalent circuit diagram according to an alternative embodiment of the invention, as shown in FIG. 3, wherein C is ∑ ＝3(C 01 +C 02 +C 03 )。
Further, it is possible to obtain:
wherein the content of the first and second substances,
is the grounding current, A;
is the power supply electromotive force, V; r is grounding resistance omega; c ∑ All capacitances to ground, F;
is the fault phase voltage, V.
According to the above formula, the neutral point voltage can be obtained by using the loop voltage method
As shown in the following formula:
based on the above analysis, the double circle method is used to show the following:
(1) With pre-fault power supplyElectromotive force
The size of (2) is that two tangent circles are made on the diameter, the tangent point of the two circles is a zero point O, and the zero point O is used as a reference point of all phasors, and fig. 4 is a steady-state voltage vector diagram of a neutral point ungrounded system according to an alternative embodiment of the invention, as shown in fig. 4.
(2) N point represents the potential of neutral point
According to
The locus of N points should be
To the left of the circumference of the diameter.
(3) Point A represents the ground point voltage, i.e. the voltage to ground of phase A after a fault, based on
The locus of the A point is
To the left of the circumference of the diameter.
(4) Due to the fact that
And
respectively representing the voltages to earth of the phase B and the phase C after the fault, and the vector size of the voltages is equal to the sum of the phase B and the phase C before the fault
The sum of (3) can be made in the figure based on step (2) by directly using the principle of phasor addition, as shown in FIG. 4And (6) discharging.
By adopting the double-circle method, the three-phase voltage to earth after single-phase earth can be clearly obtained
And
can be analyzed in detail by adding an auxiliary line LM
And
the relative sizes of the components are as follows:
a. when a phase a is brought to a single-phase metallic ground (R = 0), the phase a voltage to ground will drop to zero
The potential amplitude of the neutral point will rise to phase voltage in the opposite direction to the fault phase power supply voltage
Raising the voltage to ground of the non-faulted phases (B and C phases) to line voltage
Wherein
Phase angle ratio of
The angle is reduced by 30 degrees,
phase angle ratio of
Increased by 30.
b. When A phase ground fault disappears orIn normal operation (R = ∞), the voltage of A relative to ground becomes the normal operation voltage
The potential of the neutral point is restored to zero, and the N point is coincided with the O point
Non-faulted phases (B and C phases) recover to phase voltage from ground voltage
c. When resistive grounding occurs (R ≠ 0), the magnitude of the voltage of A relative to ground is between zero and
between
N is not coincident with O, and the potential of the neutral point is also between zero and
between
The voltages to ground of the non-failed phases (B and C phases) are shown in FIG. 4
And with
Sum, and magnitude of C-phase voltage
Will rise.
d. As shown by the auxiliary line LM in FIG. 4, when the N point is located
The amplitude of the B-phase voltage when above the vector
Will be reduced and less than the amplitude of the A-phase voltage
When N is located in
Magnitude of the B-phase voltage when below the vector
Will rise and be greater than the amplitude of the A-phase voltage
The intersection point S of the visible vector and the lower circle in the figure is
And
the demarcation point of magnitude.
The method has the advantages that the method is visual and simple, and clear and visible in conclusion, the method greatly reduces the difficulty of engineering technicians in understanding the principle that the steady-state voltage of the single-phase earth fault of the power distribution network changes along with the earth resistance, has strong practicability, and is particularly suitable for engineering application.
Example 2
According to another aspect of the embodiments of the present invention, there is also provided a three-phase voltage-to-ground processing apparatus, and fig. 5 is a schematic diagram of the three-phase voltage-to-ground processing apparatus according to the embodiments of the present invention, as shown in fig. 5, the three-phase voltage-to-ground processing apparatus including: an acquisition module 52, a first determination module 54, and a second determination module 56. The following is a detailed description of the processing device of the three-phase voltage to ground.
The acquisition module 52 is configured to acquire characteristic data of the power distribution network; a first determining module 54, connected to the obtaining module 52, for determining a voltage vector diagram of the power distribution network according to the characteristic data; and a second determining module 56, connected to the first determining module 54, for determining the three-phase voltage-to-ground after the single-phase grounding according to the voltage vector diagram of the distribution network.
It should be noted that the above modules may be implemented by software or hardware, for example, for the latter, the following may be implemented: the modules can be located in the same processor; and/or the modules are located in different processors in any combination.
In the above embodiment, the processing device for the three-phase voltage-to-ground voltage can determine the corresponding voltage vector diagram through the characteristic data of the power distribution network, and obtain the three-phase voltage-to-ground voltage after single-phase grounding by using the voltage vector diagram, so that the purpose of obtaining the steady-state voltage with clear and understandable concept and definite conclusion is achieved, the steady-state voltage of the neutral point ungrounded power distribution system is accurately and clearly expressed, the technical effect of strong practicability is achieved, and the technical problem that the steady-state voltage of the neutral point ungrounded power distribution system cannot be accurately and clearly expressed in the related technology is solved.
It should be noted here that the above-mentioned obtaining module 52, the first determining module 54 and the second determining module 56 correspond to steps S102 to S106 in embodiment 1, and the above-mentioned modules are the same as the examples and application scenarios realized by the corresponding steps, but are not limited to what is disclosed in embodiment 1 above.
In an alternative embodiment, the obtaining module 52 includes: the acquiring unit is used for acquiring characteristic parameters of the power distribution network in a steady-state process of operation with faults, wherein the characteristic parameters comprise at least one of the following parameters: ground current, power supply electromotive force, ground resistance, line-to-ground total capacitance, faulty phase voltage, and neutral voltage.
In an alternative embodiment, the three-phase voltage to ground includes a first voltage to ground, a second voltage to ground, and a third voltage to ground, and the second determining module 56 includes: the first processing unit is used for processing the voltage vector diagram of the power distribution network by using a double-circle method to obtain a first phase-to-ground voltage, a second phase-to-ground voltage and a third phase-to-ground voltage; and a second processing unit for setting a predetermined auxiliary line on a voltage vector diagram of the distribution network, and determining a relative magnitude between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage.
In an optional implementation manner, the second processing unit includes: a first processing subunit for reducing the first phase-to-earth voltage to zero when the first phase is brought to single-phase metallic ground; the magnitude of the neutral point potential will rise to a phase voltage in the opposite direction to the supply voltage of the first phase; the second phase voltage to ground and the third phase voltage to ground are raised to line voltages.
In an optional implementation manner, the second processing unit includes: a second processing subunit, configured to change the first phase-to-ground voltage to a normal operation voltage when the first phase-to-ground fault disappears or operates normally; the neutral point potential returns to zero; the second phase-to-ground voltage and the third phase-to-ground voltage are restored as phase voltages.
In an optional implementation manner, the second processing unit includes: a third processing subunit, configured to, when resistive grounding occurs, the first phase-to-ground voltage is greater than zero and less than the first phase power supply electromotive force; the neutral point potential is greater than zero and less than the first phase power supply electromotive force; the second phase-to-ground voltage is the sum of the neutral point voltage and the second phase power supply electromotive force, and the third phase-to-ground voltage is the sum of the neutral point voltage and the third phase power supply electromotive force.
Example 3
According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium including a stored program, where the program, when executed, controls a device in which the computer-readable storage medium is located to perform any one of the above processing methods for three-phase voltage to ground.
Optionally, in this embodiment, the computer-readable storage medium may be located in any one of a group of computer terminals in a computer network and/or in any one of a group of mobile terminals, and the computer-readable storage medium includes a stored program.
Optionally, the program when executed controls an apparatus in which the computer-readable storage medium is located to perform the following functions: acquiring characteristic data of the power distribution network; determining a voltage vector diagram of the power distribution network according to the characteristic data; and determining the three-phase voltage to ground after the single-phase grounding according to a voltage vector diagram of the power distribution network.
Example 4
According to another aspect of the embodiments of the present invention, there is also provided a processor, configured to execute a program, where the program executes any one of the above processing methods for three-phase voltage to ground.
An embodiment of the present invention provides an apparatus, where the apparatus includes a processor, a memory, and a program that is stored in the memory and is executable on the processor, and the processor implements the following steps when executing the program: acquiring characteristic data of the power distribution network; determining a voltage vector diagram of the power distribution network according to the characteristic data; and determining the three-phase voltage to ground after single-phase grounding according to a voltage vector diagram of the power distribution network.
The invention also provides a computer program product adapted to perform a program for initializing the following method steps when executed on a data processing device: acquiring characteristic data of the power distribution network; determining a voltage vector diagram of the power distribution network according to the characteristic data; and determining the three-phase voltage to ground after the single-phase grounding according to a voltage vector diagram of the power distribution network.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present invention, the description of each embodiment has its own emphasis, and reference may be made to the related description of other embodiments for parts that are not described in detail in a certain embodiment.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed coupling or direct coupling or communication connection between each other may be an indirect coupling or communication connection through some interfaces, units or modules, and may be electrical or in other forms.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic disk, or an optical disk, and various media capable of storing program codes.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and amendments can be made without departing from the principle of the present invention, and these modifications and amendments should also be considered as the protection scope of the present invention.
Claims (8)
1. A method for processing three-phase voltage to ground is characterized by comprising the following steps:
acquiring characteristic data of the power distribution network;
determining a voltage vector diagram of the power distribution network according to the characteristic data;
determining the three-phase voltage to earth after single-phase grounding according to the voltage vector diagram of the power distribution network;
the three-phase ground voltage comprises a first ground voltage, a second ground voltage and a third ground voltage, and the three-phase ground voltage after single-phase grounding is determined according to a voltage vector diagram of the power distribution network, and the method comprises the following steps:
processing the voltage vector diagram of the power distribution network by using a double-circle method to obtain the first phase-to-ground voltage, the second phase-to-ground voltage and the third phase-to-ground voltage;
setting a predetermined auxiliary line on a voltage vector diagram of the distribution network, and determining the relative sizes among the first phase-to-ground voltage, the second phase-to-ground voltage and the third phase-to-ground voltage;
setting a predetermined auxiliary line on a voltage vector diagram of the distribution network, determining a phase-to-ground voltage between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage, including:
when the first phase is brought to single-phase metallic ground, the first phase-to-ground voltage will drop to zero; the magnitude of the neutral point potential will rise to a phase voltage in the opposite direction to the supply voltage of the first phase; the second phase voltage to ground and the third phase voltage to ground are raised to line voltages.
2. The method of claim 1, wherein obtaining characterization data for the power distribution network comprises:
acquiring characteristic parameters of the power distribution network in a steady-state process with fault operation, wherein the characteristic parameters comprise at least one of the following parameters: ground current, power supply electromotive force, ground resistance, line-to-ground total capacitance, faulty phase voltage, and neutral voltage.
3. The method of claim 1, wherein setting a predetermined auxiliary line on a voltage vector diagram of the power distribution network, determining a magnitude of a phase-to-ground voltage between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage, comprises:
when the first phase grounding fault disappears or the first phase grounding fault operates normally, the first phase grounding voltage is changed into a normal operation voltage; the neutral point potential returns to zero; and the second phase voltage to ground and the third phase voltage to ground are recovered into phase voltages.
4. The method of claim 1, wherein setting a predetermined auxiliary line on a voltage vector diagram of the power distribution network, determining a relative magnitude between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage comprises:
when resistive grounding occurs, the first phase-to-ground voltage is greater than zero and less than a first phase power supply electromotive force; the neutral point potential is greater than zero and less than the first phase power supply electromotive force; the second phase-to-ground voltage is the sum of a neutral point voltage and a second phase power supply electromotive force, and the third phase-to-ground voltage is the sum of a neutral point voltage and a third phase power supply electromotive force.
5. A processing apparatus for the processing method of the three-phase voltage to ground of claim 1, comprising:
the acquisition module is used for acquiring characteristic data of the power distribution network;
the first determining module is used for determining a voltage vector diagram of the power distribution network according to the characteristic data;
the second determining module is used for determining the three-phase voltage to earth after single-phase grounding according to the voltage vector diagram of the power distribution network;
the three-phase voltage to ground includes a first voltage to ground, a second voltage to ground, and a third voltage to ground, and the second determining module includes:
the first processing unit is used for processing the voltage vector diagram of the power distribution network by using a double-circle method to obtain the first phase-to-ground voltage, the second phase-to-ground voltage and the third phase-to-ground voltage;
a second processing unit for setting a predetermined auxiliary line on a voltage vector diagram of the distribution network, and determining a magnitude of a phase-to-ground voltage between the first phase-to-ground voltage, the second phase-to-ground voltage, and the third phase-to-ground voltage;
the second processing unit includes:
a first processing subunit for reducing the first phase-to-ground voltage to zero when a single-phase metallic grounding occurs in the first phase; the magnitude of the neutral point potential will rise to a phase voltage in the opposite direction to the supply voltage of the first phase; the second phase voltage to ground and the third phase voltage to ground are raised to line voltages.
6. The apparatus of claim 5, wherein the obtaining module comprises:
the acquiring unit is used for acquiring characteristic parameters of the power distribution network in a steady-state process with fault operation, wherein the characteristic parameters comprise at least one of the following parameters: ground current, power supply electromotive force, ground resistance, line-to-ground total capacitance, faulty phase voltage, and neutral voltage.
7. A computer-readable storage medium, comprising a stored program, wherein when the program runs, the apparatus where the computer-readable storage medium is located is controlled to execute the processing method of three-phase voltage to ground according to any one of claims 1 to 4.
8. A processor, characterized in that the processor is configured to run a program, wherein the program is configured to execute the method of processing the three-phase voltage to ground of any one of claims 1 to 4 when running.
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