CN112332391A - Harmonic elimination method, system and device - Google Patents
Harmonic elimination method, system and device Download PDFInfo
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
The application discloses a harmonic elimination method, a harmonic elimination system and a harmonic elimination device. Wherein, the method comprises the following steps: connecting a neutral point of a primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device; short-circuiting residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase earth fault occurs; when the occurrence of a single-phase ground fault is detected, the open ends of the delta winding having the opening are connected via a target resistance. When single-phase earth fault recovered, easily appeared low frequency nonlinear oscillation among the voltage transformer in this application, very big overcurrent can appear in its high-voltage side, leads to voltage transformer fuse to cause the technical problem that voltage transformer body damaged even.
Description
Technical Field
The application relates to the technical field of power distribution networks, in particular to a harmonic elimination method, system and device.
Background
When a large capacitance current exists in a system without grounding at a neutral point of a power distribution network, a primary high-voltage fuse fusing accident of a voltage Transformer (PT) is easy to occur at the moment of single-phase grounding recovery. When the primary side high-voltage fuse of the PT fuses in a single phase, the false grounding of a system can be caused, the voltage of the opening triangle rises, and the false operation of the relay is caused.
The reason for frequent fusing of the PT fuse is mainly overcurrent caused by overvoltage. In a neutral point non-effective grounding system, the overvoltage with larger threat mainly comprises lightning overvoltage, operation overvoltage, ferromagnetic resonance overvoltage and low-frequency nonlinear oscillation, and for the first three types of overvoltage, at present, mature and effective measures are provided, but for the low-frequency nonlinear oscillation which appears after the capacitance current of the system is increased, the low-frequency nonlinear oscillation is still easy to be excited under common operations such as single-phase grounding, no-load bus closing and the like. The magnetizing inrush current and the discharge current of the capacitor can generate continuous impact on the PT high-voltage side fuse.
The low frequency nonlinear oscillation is caused by the energy oscillation between the line-to-ground capacitance and the PT nonlinear excitation inductance. When a single-phase earth fault occurs, a non-fault phase voltage is changed from a line voltage to a phase voltage, a part of charges on a line-to-earth capacitor of the non-fault phase voltage lose voltage support to become free charges due to reduction of voltage, the free charges are discharged to the ground through a neutral point on a high-voltage side of a bus PT, impact on a PT high-voltage winding, cause saturation of the PT high-voltage winding, and reduce excitation inductance. But since the system parameters are outside the range of ferroresonance, low frequency nonlinear oscillations occur at this time. Compared with ferromagnetic resonance, the overcurrent of the PT high-voltage winding caused by low-frequency nonlinear oscillation is extremely serious, and because the oscillation frequency is very low and the attenuation is very quick, in this case, the PT high-voltage fuse is subjected to an adiabatic process, and is very easy to damage or even explode.
In view of the above problems, no effective solution has been proposed.
Disclosure of Invention
The embodiment of the application provides a harmonic elimination method, a harmonic elimination system and a harmonic elimination device, and the technical problem that when a single-phase earth fault is recovered, low-frequency nonlinear oscillation easily occurs in a voltage transformer, and a high-voltage side of the voltage transformer can generate extremely large overcurrent, so that the fuse of the voltage transformer is fused, and even a voltage transformer body is damaged is solved.
According to an aspect of an embodiment of the present application, there is provided a harmonic cancellation method including: connecting a neutral point of a primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device; short-circuiting residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase ground fault occurs; when the single-phase earth fault is detected, the two open ends of the triangular winding with the opening are connected through a target resistor.
Optionally, after connecting the neutral point of the primary winding of the three-phase voltage transformer to the ground through the nonlinear resistance resonance elimination damping device, the method further includes: and discharge gaps are connected in parallel at two ends of the nonlinear resistance harmonic elimination damping device.
Optionally, when the single-phase ground fault is detected, before connecting the two open ends of the triangular winding with the opening through the target resistor, the method further includes: and acquiring a zero sequence voltage amplitude of the three-phase voltage transformer, and determining that the single-phase earth fault occurs when the zero sequence voltage amplitude exceeds a preset threshold value.
Optionally, obtaining a zero-sequence voltage amplitude of the three-phase voltage transformer includes: and detecting voltages at two open ends of the triangular winding with the opening, wherein the voltages are used for indicating the zero sequence voltage amplitude of the three-phase voltage transformer.
Optionally, the nonlinear resistive resonance elimination damping device comprises: pressure-sensitive or heat-sensitive resonance-eliminating damping devices.
According to another aspect of the embodiments of the present application, there is also provided a harmonic cancellation system, including: the system comprises three-phase voltage transformers, wherein each single-phase voltage transformer is provided with a residual winding, and the residual winding is used for generating residual voltage when a single-phase earth fault occurs; the nonlinear resistance harmonic elimination damping device is connected with the three-phase voltage transformer, wherein a neutral point of a primary side winding of the three-phase voltage transformer is connected with the ground through the nonlinear resistance harmonic elimination damping device; and the three residual windings are used for forming a triangular winding with an opening in a short circuit mode, and the voltage at two ends of the opening of the triangular winding with the opening is used for indicating the zero sequence voltage amplitude of the three-phase voltage transformer.
Optionally, the system further comprises: a target resistor for connecting the open ends of the triangular winding with the opening via the target resistor when the single-phase ground fault is detected
According to another aspect of the embodiments of the present application, there is also provided a harmonic cancellation apparatus, including: the first processing module is used for connecting a neutral point of a primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device; the second processing module is used for short-circuiting the residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase earth fault occurs; and the third processing module is used for connecting the two open ends of the triangular winding with the opening through a target resistor when the single-phase ground fault is detected.
Optionally, the third processing module includes: the acquisition module acquires a zero sequence voltage amplitude of the three-phase voltage transformer; the determining module is used for determining that the single-phase earth fault occurs when the zero-sequence voltage amplitude exceeds a preset threshold; and the execution module is used for connecting the two open ends of the triangular winding with the opening through a target resistor when the single-phase ground fault is determined to occur.
According to another aspect of the embodiments of the present application, there is also provided a non-volatile storage medium, which includes a stored program, wherein when the program runs, a device in which the non-volatile storage medium is located is controlled to execute the above-mentioned harmonic elimination method.
In the embodiment of the application, a neutral point of a primary side winding of a three-phase voltage transformer is connected with the ground through a nonlinear resistance harmonic elimination damping device; short-circuiting residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase earth fault occurs; when the single-phase ground fault is detected, the two ends of the opening of the triangular winding with the opening are connected through the target resistor, primary harmonic elimination is achieved through the nonlinear resistor harmonic elimination damping device, secondary harmonic elimination is achieved through the two ends of the opening of the triangular winding with the opening through the target resistor, resonance in the voltage transformer is effectively restrained, and therefore the technical problem that when the single-phase ground fault is recovered, low-frequency nonlinear oscillation easily occurs in the voltage transformer, large overcurrent can occur on the high-voltage side of the voltage transformer, fuse of the voltage transformer is caused, and even the voltage transformer body is damaged is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
FIG. 1 is a schematic flow diagram of a harmonic cancellation method according to an embodiment of the present application;
FIG. 2 is a circuit schematic of harmonic cancellation according to an embodiment of the present application;
FIG. 3 is a schematic circuit diagram of harmonic cancellation according to an embodiment of the present application;
FIG. 4a is a schematic diagram of a harmonic cancellation system according to an embodiment of the present application;
FIG. 4b is a schematic diagram of another harmonic cancellation system according to an embodiment of the present application;
FIG. 5a is a schematic diagram of a harmonic cancellation apparatus according to an embodiment of the present application;
fig. 5b is a schematic structural diagram of another harmonic cancellation apparatus according to an embodiment of the present application.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all 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 application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application 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 application described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, 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 application, there is provided an embodiment of a harmonic cancellation method, it is 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 while 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.
In the power system, the low-frequency nonlinear oscillation generation principle is as follows: when a single-phase earth fault occurs in a 10kV system (taking a-phase earth as an example), the current flowing through the earth point is:
in the formula C11Is a line-to-ground capacitance, and L is the primary winding inductance of the voltage transformer. EmThe amplitude of the electromotive force is the A-phase electromotive force EaThe instantaneous value expression of (a) is:
the instantaneous value expression for the ground current can be expressed accordingly as:
the current source and impedance are laplace transformed, respectively:
in the formula:
while
Therefore, the transient voltage appearing at the two ends of the high-voltage winding of the voltage transformer is as follows:
inverse transformation of the above formula can obtain:
in the formula (I), the compound is shown in the specification,
and the first term in the equation above, to the right of the middle sign, is the mandatory component of voltage, which does not attenuate. The latter two terms are free components of voltage, which are to be attenuated due to the inevitable presence of resistance in the circuit, and can be expressed approximately by the attenuation coefficient delta due to the small relative value of resistance, thereby
In the formula (I), the compound is shown in the specification,
from the above equation, the amplitude of the voltage free oscillation component is the initial phase angle
As a function of (c). Under this condition, when the amplitude of the free oscillation is maximum, and when Φ ± 90 °, the amplitude of the free oscillation is minimum. The relation between voltage and flux linkage is combined as follows:
in the formula (I), the compound is shown in the specification,
due to the fact thatΨRepresenting the free-running flux linkage, the integration constant C in the above equation may be considered zero. As can be seen from the above equation, the free flux linkage component is related to the free oscillation frequency in addition to the initial phase angle. Under the influence of free oscillation magnetic flux, the iron core of the voltage transformer is saturated once every half of a free oscillation period (the value of the iron core is far greater than a power frequency period), each saturation is accompanied by an impact current including the power frequency current, and the PT high-voltage fuse is impacted once and once.
Based on the principle of low-frequency nonlinear oscillation generation, the embodiment of the application provides that a primary harmonic elimination measure and a secondary harmonic elimination measure are adopted for the voltage transformer to inhibit fuse blowout, wherein a nonlinear resistance harmonic elimination damping device is additionally arranged between a neutral point of a primary winding of the voltage transformer and the ground to achieve the effect of inhibiting resonance; and connecting a resistor at two ends of the triangular winding with the opening of the voltage transformer, so that the resonance energy is released through the resistor.
Fig. 1 is a schematic flow chart of a harmonic cancellation method according to an embodiment of the present application, as shown in fig. 1, the method at least includes steps S102-S106, where:
and S102, connecting the neutral point of the primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device.
In the embodiment of the application, a nonlinear resistance resonance elimination damping device is additionally arranged between the neutral point of the primary side winding of the voltage transformer and the ground, so that the effect of inhibiting resonance is achieved, and the process can be called as primary resonance elimination. Wherein, the damping device of the harmonic elimination of the nonlinear resistor is called as a harmonic elimination device, including: pressure-sensitive or heat-sensitive resonance-eliminating damping devices.
Taking a pressure-sensitive resonance elimination damping device as an example, the nonlinear resistor is formed by burning SiC which is used as a main raw material in a high-temperature hydrogen furnace and connecting a plurality of resistors in series and parallel, when the nonlinear resistor is applied to the normal operation of a power grid, the voltage on a resonance eliminator is not high and is high in resistance (about 0.5M), so that resonance is not easy to occur in the initial stage; when the power grid is grounded in a single phase, the voltage on the resonance eliminator is high (10kV power grid, the voltage on the resonance eliminator is 1.7-1.8 kV), the resistance is low (the resonance elimination resistance of the 10kV power grid is reduced to tens of thousands of ohms), and the requirement that the voltage of the PT open-ended triangular winding is not less than 80V can be met.
In this embodiment of the present application, after connecting the neutral point of the primary winding of the three-phase voltage transformer to the ground through the non-linear resistance resonance elimination damping device, the method further includes: and discharge gaps are connected in parallel at two ends of the nonlinear resistance harmonic elimination damping device.
Specifically, due to three-phase asymmetry of a line in a power system, zero sequence voltage and zero sequence current exist in the line for a long time, the zero sequence current flows into the ground through the resonance elimination damping device to generate potential on the resonance elimination damping device, and the potential depends on the asymmetry degree of the line. In the process of suppressing resonance, as the resonance elimination damping device needs to absorb a large amount of energy, larger transient overvoltage can be generated, and the overvoltage can endanger the insulation of the neutral point on the high-voltage side of the voltage transformer, when the primary resonance elimination device is applied to suppress the high-voltage fuse fusing phenomenon, the fully-insulated voltage transformer is adopted as much as possible, and the two ends of the resonance elimination damping device are connected with discharge gaps in parallel to protect the insulation of the neutral point on the high-voltage side of the voltage transformer.
In an optional embodiment of the application, a simulation experiment is carried out on the primary harmonic elimination method of the voltage transformer, and an experiment result shows that for an electromagnetic transient process under different capacitance parameters, after a primary harmonic elimination device is additionally arranged, primary side overvoltage of the voltage transformer can be effectively inhibited, and voltage of a power grid can be quickly recovered to a stable state after a single-phase ground fault disappears; and the magnetizing inrush current and overcurrent multiple of the voltage transformer are reduced, the most serious low-frequency nonlinear oscillation parameter is also within the thermal capacity range of the fuse, and the fuse cannot be fused.
And step S104, short-circuiting the residual windings on the secondary side of the three-phase voltage transformer to form triangular windings with openings.
And step S106, when the single-phase earth fault is detected to occur, connecting the two open ends of the triangular winding with the opening through a target resistor.
In the embodiment of the present application, the open ends of the triangular winding with the opening are connected via the target resistor, so as to achieve the effect of suppressing resonance, which may be referred to as second harmonic elimination, and the circuit diagram is shown in fig. 2.
Specifically, the closed winding with the open delta winding and the open delta winding connected through the target resistor at the two ends is called a secondary resonance elimination device, which is equivalent to a resistor R connected in parallel with the high-voltage winding of the voltage transformereqAs shown in FIG. 3, wherein Req＝K13 2×r，K13Is the transformation ratio between the primary winding of the voltage transformer and the triangular winding with the opening. ReqConnected in parallel with the exciting inductor of the voltage transformer, once the system resonates, the effect of the inductor is reduced, and the resonant energy is released through the resistorThe smaller the resistance connected, the less the nonlinear inductance affects the circuit, and the more the resonance can be suppressed.
The key of the secondary harmonic elimination lies in the accuracy of resonance detection and the rapidity of input, the zero sequence voltage amplitude of the voltage transformer is generally collected, when the zero sequence voltage is detected to exceed a preset threshold value, the system is considered to be in resonance, and then the two ends of the opening of the triangular winding with the opening in the voltage transformer are connected through the target resistor in a short time.
In an embodiment of the present application, before connecting the two open ends of the delta winding having the opening to the target resistor when the single-phase ground fault is detected, the method further includes: and acquiring a zero sequence voltage amplitude of the three-phase voltage transformer, and determining that the single-phase earth fault occurs when the zero sequence voltage amplitude exceeds a preset threshold value.
Specifically, obtaining the zero sequence voltage amplitude of the three-phase voltage transformer includes: and detecting voltages at two open ends of the triangular winding with the opening, wherein the voltages are used for indicating the zero sequence voltage amplitude of the three-phase voltage transformer.
In an alternative embodiment of the present application, three remaining windings on the secondary side of the three-phase voltage transformer may be connected in series with the remaining windings of the zero-sequence voltage transformer as a monitoring signal of the zero-sequence voltage, and at this time, since the zero-sequence voltage measurement circuit is formed by connecting the open-delta winding of the three-phase voltage transformer and the remaining windings of the zero-sequence voltage transformer in series according to the positive polarity, it contains a small portion of the zero-sequence voltage of the three-phase voltage transformer, and the measurement is more accurate than the measurement of the zero-sequence voltage directly by the remaining windings of the zero. Meanwhile, because the zero sequence loop is not in short circuit, the hidden trouble that the open angle winding is burnt out due to insufficient heat capacity caused by the capacitor discharge current is avoided.
In an optional embodiment of the present application, a simulation experiment is performed on a voltage transformer second harmonic elimination method. Firstly, under the condition that a voltage transformer is provided with a secondary resonance elimination device, the oscillation of a suppression system during elimination of single-phase grounding short circuit is simulated according to different grounding capacitance sizes, according to the simulation result, after a single-line short circuit grounding fault occurs, the switching interval is 0.015s, and when the switching frequency is 3 times, the method can effectively suppress the generation of power frequency ferromagnetic resonance and prevent the fuse of the voltage transformer; with the increase of the circuit, the equivalent ground capacitance can be increased, so that the protection effect of the secondary resonance elimination device in the range of frequency division resonance and low-frequency nonlinear oscillation is continuously researched, for different parameters (switching interval, switching times, energy-absorbing capacitor C and discharge resistor R), the influence of each parameter on the secondary resonance elimination method is researched by adopting a control variable method, and the result shows that: the influence of the switching interval and the switching frequency on the harmonic elimination effect is small, the reason for analyzing the harmonic elimination effect is that the key time for eliminating the electromagnetic oscillation is the moment when the oscillation just starts to occur, at the moment, if the electromagnetic energy of the earth capacitance and the PT winding can be consumed, the oscillation is prevented from being generated, once the oscillation is generated, the energy can be continuously absorbed from a system power supply, the power consumed by the secondary side is small relative to the primary side, and the oscillation is difficult to eliminate. Meanwhile, the resonance elimination effect cannot be improved by simply increasing the energy-absorbing capacitor C, but the discharge resistor R needs to be reduced in a matched manner, and the smaller the time constant of the RC loop is, the better the overvoltage is restrained.
In the embodiment of the application, a neutral point of a primary side winding of a three-phase voltage transformer is connected with the ground through a nonlinear resistance harmonic elimination damping device; short-circuiting residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase earth fault occurs; when the single-phase ground fault is detected, the two ends of the opening of the triangular winding with the opening are connected through the target resistor, primary harmonic elimination is achieved through the nonlinear resistor harmonic elimination damping device, secondary harmonic elimination is achieved through the two ends of the opening of the triangular winding with the opening through the target resistor, resonance in the voltage transformer is effectively restrained, and therefore the technical problem that when the single-phase ground fault is recovered, low-frequency nonlinear oscillation easily occurs in the voltage transformer, large overcurrent can occur on the high-voltage side of the voltage transformer, fuse of the voltage transformer is caused, and even the voltage transformer body is damaged is solved.
Example 2
There is also provided, in accordance with an embodiment of the present application, a harmonic cancellation system, as shown in fig. 4, including at least a three-phase voltage transformer 40, a non-linear resistive resonance cancellation damping device 42, and three residual windings 44, wherein:
three-phase voltage transformers 40, wherein each single-phase voltage transformer is provided with a residual winding for generating residual voltage when a single-phase earth fault occurs;
the nonlinear resistance resonance elimination damping device 42 is connected with the three-phase voltage transformer, wherein a neutral point of a primary side winding of the three-phase voltage transformer is connected with the ground through the nonlinear resistance resonance elimination damping device;
and three residual windings 44 for short-circuiting to form a triangular winding with an opening, wherein the voltage across the opening of the triangular winding with the opening is used for indicating the zero sequence voltage amplitude of the three-phase voltage transformer.
In the embodiment of the application, a nonlinear resistance resonance elimination damping device is additionally arranged between the neutral point of the primary side winding of the voltage transformer and the ground, so that the effect of suppressing resonance is achieved, and the process can be called primary resonance elimination, wherein the nonlinear resistance resonance elimination damping device is called a primary resonance elimination device.
In an optional embodiment of the present application, the system further comprises: the target resistor 46, as shown in fig. 4b, connects the open ends of the delta winding having the opening through the target resistor when the occurrence of the single-phase ground fault is detected.
Specifically, the open ends of the triangular winding with the opening are connected through the target resistor, so as to achieve the effect of suppressing resonance, and this process can be referred to as second harmonic elimination.
The embodiment of the application provides that a primary harmonic elimination measure and a secondary measure are adopted for a voltage transformer to inhibit fuse, wherein a nonlinear resistance harmonic elimination damping device is additionally arranged between a neutral point of a primary winding of the voltage transformer and the ground to achieve the effect of inhibiting resonance; and connecting a resistor at two ends of the triangular winding with the opening of the voltage transformer, so that the resonance energy is released through the resistor.
It should be noted that, reference may be made to the relevant description in embodiment 1 for a preferred implementation of this embodiment, and details are not described here again.
Example 3
According to an embodiment of the present application, there is also provided a harmonic cancellation apparatus, as shown in fig. 5a, the apparatus includes at least a first processing module 50, a second processing module 52, and a third processing module 54, wherein:
the first processing module 50 is used for connecting a neutral point of a primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device;
the second processing module 52 is configured to short-circuit the remaining windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, where each single-phase voltage transformer is provided with one remaining winding, and the remaining windings are used to generate remaining voltage when a single-phase ground fault occurs;
and a third processing module 54 for connecting the two open ends of the delta winding having the opening via a target resistance when the occurrence of the single-phase ground fault is detected.
The embodiment of the application provides that a primary harmonic elimination measure and a secondary measure are adopted for a voltage transformer to inhibit fuse, wherein a nonlinear resistance harmonic elimination damping device is additionally arranged between a neutral point of a primary winding of the voltage transformer and the ground to achieve the effect of inhibiting resonance; and connecting a resistor at two ends of the triangular winding with the opening of the voltage transformer, so that the resonance energy is released through the resistor.
In this embodiment of the application, the third processing module 54 further includes an obtaining module 540, a determining module 542 and an executing module 544, as shown in fig. 5b, where:
the obtaining module 540 is used for obtaining the zero sequence voltage amplitude of the three-phase voltage transformer;
the determining module 542 is configured to determine that a single-phase ground fault occurs when the zero-sequence voltage amplitude exceeds a preset threshold;
a block 544 is executed to connect the open ends of the delta winding with openings via the target resistance when it is determined that a single-phase ground fault has occurred.
The key of the secondary harmonic elimination lies in the accuracy of resonance detection and the rapidity of input, the zero sequence voltage amplitude of the voltage transformer is generally collected, when the zero sequence voltage is detected to exceed a preset threshold value, the system is considered to be in resonance, and then the two ends of the opening of the triangular winding with the opening in the voltage transformer are connected through the target resistor in a short time.
It should be noted that, reference may be made to the relevant description in embodiment 1 for a preferred implementation of this embodiment, and details are not described here again.
Example 4
According to an embodiment of the present application, there is also provided a nonvolatile storage medium including a stored program, wherein the apparatus in which the nonvolatile storage medium is controlled to execute the above-mentioned harmonic cancellation method when the program is executed.
Optionally, the apparatus in which the non-volatile storage medium is controlled when the program is running executes the following steps: connecting a neutral point of a primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device; short-circuiting residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase earth fault occurs; when the occurrence of a single-phase ground fault is detected, the open ends of the delta winding having the opening are connected via a target resistance.
Optionally, the apparatus in which the non-volatile storage medium is controlled when the program is running executes the following steps: after a neutral point of a primary side winding of the three-phase voltage transformer is connected with the ground through the nonlinear resistance harmonic elimination damping device, two ends of the nonlinear resistance harmonic elimination damping device are connected with a discharge gap in parallel.
Optionally, the apparatus in which the non-volatile storage medium is controlled when the program is running executes the following steps: when the single-phase earth fault is detected, the zero sequence voltage amplitude of the three-phase voltage transformer is obtained before the two ends of the opening of the triangular winding with the opening are connected through the target resistor, and when the zero sequence voltage amplitude exceeds a preset threshold value, the single-phase earth fault is determined to occur. Wherein, obtain three-phase voltage transformer's zero sequence voltage amplitude, include: and detecting voltages at two open ends of the triangular winding with the opening, wherein the voltages are used for indicating the zero sequence voltage amplitude of the three-phase voltage transformer.
It should be noted that, reference may be made to the relevant description in embodiment 1 for a preferred implementation of this embodiment, and details are not described here again.
The above-mentioned serial numbers of the embodiments of the present application are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present application, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
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 mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
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 application 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 application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in 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 application. 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 or optical disk, and other various media capable of storing program codes.
The foregoing is only a preferred embodiment of the present application and it should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.
Claims (10)
1. A method of harmonic cancellation, comprising:
connecting a neutral point of a primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device;
short-circuiting residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase ground fault occurs;
when the single-phase earth fault is detected, the two open ends of the triangular winding with the opening are connected through a target resistor.
2. The method of claim 1, wherein after connecting the primary winding neutral point of the three-phase voltage transformer to ground through the nonlinear resistance resonance elimination damping device, the method further comprises:
and discharge gaps are connected in parallel at two ends of the nonlinear resistance harmonic elimination damping device.
3. The method according to claim 1, wherein before connecting the open ends of the delta winding with an opening through a target resistance when the occurrence of the single-phase ground fault is detected, the method further comprises:
and acquiring a zero sequence voltage amplitude of the three-phase voltage transformer, and determining that the single-phase earth fault occurs when the zero sequence voltage amplitude exceeds a preset threshold value.
4. The method of claim 3, wherein obtaining zero sequence voltage magnitudes of the three-phase voltage transformer comprises:
and detecting voltages at two open ends of the triangular winding with the opening, wherein the voltages are used for indicating the zero sequence voltage amplitude of the three-phase voltage transformer.
5. The method of any of claims 1-4, wherein the nonlinear resistive resonance elimination damping device comprises: pressure-sensitive or heat-sensitive resonance-eliminating damping devices.
6. A harmonic cancellation system, comprising:
the system comprises three-phase voltage transformers, wherein each single-phase voltage transformer is provided with a residual winding, and the residual winding is used for generating residual voltage when a single-phase earth fault occurs;
the nonlinear resistance harmonic elimination damping device is connected with the three-phase voltage transformer, wherein a neutral point of a primary side winding of the three-phase voltage transformer is connected with the ground through the nonlinear resistance harmonic elimination damping device;
and the three residual windings are used for forming a triangular winding with an opening in a short circuit mode, and the voltage at two ends of the opening of the triangular winding with the opening is used for indicating the zero sequence voltage amplitude of the three-phase voltage transformer.
7. The system of claim 6, further comprising:
and the target resistor is used for connecting the two open ends of the triangular winding with the opening through the target resistor when the single-phase ground fault is detected.
8. A harmonic cancellation apparatus, comprising:
the first processing module is used for connecting a neutral point of a primary side winding of the three-phase voltage transformer with the ground through a nonlinear resistance harmonic elimination damping device;
the second processing module is used for short-circuiting the residual windings on the secondary sides of the three-phase voltage transformers to form triangular windings with openings, wherein each single-phase voltage transformer is provided with one residual winding, and the residual windings are used for generating residual voltage when a single-phase earth fault occurs;
and the third processing module is used for connecting the two open ends of the triangular winding with the opening through a target resistor when the single-phase ground fault is detected.
9. The apparatus of claim 8, wherein the third processing module comprises:
the acquisition module acquires a zero sequence voltage amplitude of the three-phase voltage transformer;
the determining module is used for determining that the single-phase earth fault occurs when the zero-sequence voltage amplitude exceeds a preset threshold;
and the execution module is used for connecting the two open ends of the triangular winding with the opening through a target resistor when the single-phase ground fault is determined to occur.
10. A non-volatile storage medium, comprising a stored program, wherein the apparatus in which the non-volatile storage medium is located is controlled to perform the harmonic cancellation method according to any one of claims 1 to 5 when the program is executed.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114994465A (en) * | 2022-08-01 | 2022-09-02 | 西安兴汇电力科技有限公司 | Single-phase high-resistance grounding criterion method based on impedance triangle type high-voltage overhead line |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104466941A (en) * | 2014-12-24 | 2015-03-25 | 国家电网公司 | Combined resonance eliminating device suitable for 4PT |
| CN105182019A (en) * | 2015-08-28 | 2015-12-23 | 国家电网公司 | Device and system for reducing number of fusing times of fuse protector |
| CN109510168A (en) * | 2018-12-19 | 2019-03-22 | 国网北京市电力公司 | Mode of connection, the apparatus and system of voltage transformer |
| CN110323731A (en) * | 2019-07-03 | 2019-10-11 | 张安斌 | Voltage transformer primary side neutral point controllable impedance harmonic elimination apparatus |
| US20200287379A1 (en) * | 2018-05-04 | 2020-09-10 | Nr Electric Co., Ltd | Method and device for quickly eliminating ferromagnetic resonance of voltage transformer |
| CN211578569U (en) * | 2020-04-22 | 2020-09-25 | 大唐贵州发耳发电有限公司 | Circuit for preventing mutual inductor from resonating |
-
2020
- 2020-11-24 CN CN202011331591.2A patent/CN112332391A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104466941A (en) * | 2014-12-24 | 2015-03-25 | 国家电网公司 | Combined resonance eliminating device suitable for 4PT |
| CN105182019A (en) * | 2015-08-28 | 2015-12-23 | 国家电网公司 | Device and system for reducing number of fusing times of fuse protector |
| US20200287379A1 (en) * | 2018-05-04 | 2020-09-10 | Nr Electric Co., Ltd | Method and device for quickly eliminating ferromagnetic resonance of voltage transformer |
| CN109510168A (en) * | 2018-12-19 | 2019-03-22 | 国网北京市电力公司 | Mode of connection, the apparatus and system of voltage transformer |
| CN110323731A (en) * | 2019-07-03 | 2019-10-11 | 张安斌 | Voltage transformer primary side neutral point controllable impedance harmonic elimination apparatus |
| CN211578569U (en) * | 2020-04-22 | 2020-09-25 | 大唐贵州发耳发电有限公司 | Circuit for preventing mutual inductor from resonating |
Non-Patent Citations (1)
| Title |
|---|
| 王鹏等: "35 kV 中性点经消弧线圈接地系统几种铁磁谐振消谐措施有效性分析", 《电瓷避雷器》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114994465A (en) * | 2022-08-01 | 2022-09-02 | 西安兴汇电力科技有限公司 | Single-phase high-resistance grounding criterion method based on impedance triangle type high-voltage overhead line |
| CN114994465B (en) * | 2022-08-01 | 2022-11-22 | 西安兴汇电力科技有限公司 | Impedance triangle-based high-voltage overhead line single-phase high-resistance grounding criterion method |
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