CN112909912A - Power distribution network single-phase earth fault current full-compensation method and device - Google Patents
Power distribution network single-phase earth fault current full-compensation method and device Download PDFInfo
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Abstract
The invention discloses a single-phase earth fault current full-compensation method and a single-phase earth fault current full-compensation device for a power distribution network, wherein the method comprises the following steps: s1: two terminals on one side of a step-up transformer are respectively connected with 2 terminals led out from the secondary side of a Z-shaped grounding transformer to obtain voltage opposite to the voltage of a neutral point relative to a fault, and the voltage of the fault phase is restrained below arc quenching voltage after being boosted by the step-up transformer; the Z-type grounding transformer is connected to a power distribution network, the tail ends of phase-shifting windings of the Z-type grounding transformer are connected in a star mode to form a neutral point O, terminals of a secondary side A, B, C three-phase lead-out wiring terminal are formed, the terminals led out of the secondary side are used for selectively connecting terminals of a low-voltage side of the booster transformer, one end of a high-voltage side of the booster transformer is electrically connected with the neutral point O, and the other end of the high-voltage side of the booster transformer is connected. According to the invention, a voltage opposite to the neutral point voltage of the fault is generated through the Z-shaped grounding transformer and the boosting transformer, so that the fault current is suppressed to 0.
Description
Technical Field
The invention belongs to the technical field of single-phase earth fault processing of a power distribution network, and particularly relates to a full compensation method and device for single-phase earth fault current of the power distribution network.
Background
The power distribution network goes deep into a population activity dense area of the user terminal, the operation mode and the environmental working conditions are complex and changeable, more than 90% of faults of the power distribution network are single-phase earth faults, and the earth fault current is capacitance current and resistive leakage current due to the fact that the power distribution network has capacitance and leakage resistance to earth. In order to limit the grounding fault current, the power distribution network generally limits the grounding fault current in modes of ungrounded, resonance grounding, resistance grounding and the like, but with the increase of the capacity of the power distribution network and the increase of the proportion of cable lines, the active current component of the fault point current is gradually increased, the fault point electric arc is difficult to extinguish automatically, fault overvoltage is easy to generate, multiple accidents are caused, even large-area power failure is caused, the safety of the power distribution network is endangered, and the social stability is influenced. The fault current full compensation can effectively compensate reactive and active current components in the fault current, reduce fault point current, inhibit fault overvoltage and reduce fault arc rate.
The existing fault current full compensation method is a fault current flexible full compensation method which needs to be additionally provided with power electronic inverter equipment at a neutral point, zero sequence current is injected into the neutral point through the power electronic inverter to realize fault current flexible full compensation after a fault occurs, but the power electronic inverter equipment added by the method is expensive and needs to measure system parameters in advance, the fault current full compensation effect depends on the measurement accuracy of power distribution network parameters, and when the capacity of a power distribution network is large, the injection capacity of the power electronic equipment cannot meet the requirement of full compensation easily. Therefore, the method and the device for fully compensating the single-phase earth fault current, which do not need to be supplied with additional independent power sources and reduce the equipment cost, can be researched and developed in the next step.
The method can be mainly divided into two types: the first one is a fault active transfer method, which needs to install a fast grounding switch on a bus in a transformer substation, and when a single-phase grounding fault of a power distribution network is detected, the fast grounding switch is closed with a fault phase of the bus according to a fault phase selection result, so that a fault current is transferred to the fast grounding switch, and the magnitude of the fault current of a grounding point of the power distribution network is limited.
Disclosure of Invention
The invention aims to provide a method and a device for fully compensating single-phase earth fault current of a power distribution network, which solve the problems that an independent external power supply is needed and the equipment cost is high in the conventional compensation method.
On one hand, the invention provides a single-phase earth fault current full-compensation method for a power distribution network, which comprises the following steps: s1: two terminals on one side of a step-up transformer are respectively connected with 2 terminals led out from the secondary side of a Z-shaped grounding transformer to obtain voltage opposite to the voltage of a neutral point relative to a fault, and the voltage of the fault phase is restrained below arc quenching voltage after being boosted by the step-up transformer;
the Z-type grounding transformer is connected to a power distribution network, the tail ends of phase-shifting windings of the Z-type grounding transformer are connected in a star mode to form a neutral point O, terminals of a secondary side A, B, C three-phase lead-out wiring terminal are formed, the terminals led out of the secondary side are used for selectively connecting terminals of a low-voltage side of the booster transformer, one end of a high-voltage side of the booster transformer is electrically connected with the neutral point O, and the other end of the high-voltage side of the booster transformer is connected.
More preferably, the turn ratio of the primary side and the secondary side of the Z-type grounding transformer is N1:N2The high-voltage side of the step-up transformer is provided with n gears and the high-voltage side is provided with a voltage-regulating tapping tap KCThe boosting transformer is initially provided with a voltage-regulating tapping tap KCIn the gear n, the transformation ratio of the initial state is
When voltage regulating tapping tap KCAt the gear i, the transformation ratio of the boosting transformer is
i is a positive integer; and after executing step S1, the method further includes the steps of:
s2: delaying for a preset time t;
s3: based on adjust pressure regulating tapping KCContinuously changing the transformation ratio of the boosting transformer in the connected gear, and recording the zero sequence current of the power distribution network after the transformation ratio is changed each time;
wherein if the zero sequence current follows the voltage-regulating tapping tap KCThe change of the connected gear is nonlinear change, and the fault does not disappear; if the zero sequence current follows the voltage-regulating tapping tap KCThe change of the connected gear is linear change, and the fault disappears.
The research of the invention finds that when the fault of the power distribution network exists, the effective value of the zero sequence current of the power distribution network is tapped with a tap K along with the voltage regulationCThe gears are in nonlinear change; when the fault of the power distribution network disappears, the effective value of the zero sequence current of the power distribution network is tapped with tap K along with the voltage regulationCThe gears are changed in a linear mode, so that whether the fault disappears or not is mainly identified according to the rule, the neutral point always has the external zero sequence voltage in the identification process, the neutral point cannot lose the external voltage suddenly, and the fault current cannot be increased suddenlyAnd as a result of phase selection, the fast grounding switch and the fault phase of the bus are closed, so that fault current is transferred to the fast grounding switch, and the magnitude of the fault current of the grounding point of the power distribution network is limited. "C (B)
Further preferably, the zero sequence current is judged to be along with the voltage-regulating tapping tap KCWhether the change of the connected gear is linear or not is determined by zero sequence current and the voltage-regulating tap KCWhether the absolute value of the correlation coefficient of the gear is larger than or equal to a preset threshold value or not, and if the absolute value of the correlation coefficient of the gear is larger than or equal to the preset threshold value, the absolute value changes linearly; otherwise, the change is nonlinear.
Further preferably, the calculation formula of the correlation coefficient is as follows:
where r represents a correlation coefficient and i represents the voltage regulation tap KCThe connected gear is that I is more than or equal to 1 and less than or equal to n, I0iIndicating said voltage regulating tap KCAnd the zero sequence current of the power distribution network when the gear i is connected.
Preferably, the high-voltage side of the step-up transformer is further provided with a tap K for tapping the voltage for regulating voltageCParallel protection tapping KBSaid protection tap KBWith protective resistor, the voltage-regulating tap KCAnd said protection tap KBAre all connected in series with a switch S, and the switch S controls the on-off of the high-voltage side and the neutral point O.
Further preferably, the voltage-regulating tap K is adjustedCIn the process of gear shifting, the voltage-regulating tap K is changedCWhen the gear is connected, the protection tapping joint KBThe high-pressure side gear is switched on; waiting for the voltage-regulating tapping tap KCAfter connection, the protective tapping tap K is disconnectedBWith high-pressure side gearThe zero sequence current of the power distribution network is recorded by the connection between the voltage-regulating tapping taps K, and the voltage-regulating tapping taps K are sequentially regulated by repeating the stepsCThe connection with a high-pressure side gear;
specifically, one adjustment sequence is: firstly, the voltage-regulating tapping tap K is regulatedCAnd said protection tap KBUntil the gear is consistent with the gear; then changing the voltage-regulating tap KCThe protection tapping joint K is disconnected again when the gear is connectedBThe zero sequence current of the power distribution network is recorded by the connection between the high-voltage side gears; repeating the steps to sequentially adjust the voltage-regulating tapping tap KCThe connection with a high-pressure side gear;
the other regulating sequence is as follows: adjusting the protection tapping to a gear which is one level lower than Kc; then changing the voltage regulating tap Kc and the voltage regulating tap KBThe protection tapping tap K is disconnected again until the connected gears are consistentBThe zero sequence current of the power distribution network is recorded by the connection between the high-voltage side gears; repeating the steps to sequentially adjust the voltage-regulating tapping tap KCThe connection with a high-pressure side gear;
if the fault has disappeared, the switch S is disconnected and the voltage-regulating tap K is restoredCAnd said protection tap KBTo n-gear, and disconnecting the boosting transformer from the Z-type grounding transformer;
if the fault does not disappear, the voltage regulating tapping tap K is adjustedCConnecting with n gear, and disconnecting the protective tapping joint KBAnd the connection with the high-pressure side gear waits for fault processing.
Further preferably, when the fault is extinguished, the connection between the step-up transformer and the Z-type grounding transformer is: if the wiring mode of the Z-shaped grounding transformer is ZNY11, one terminal of the low-voltage side of the boosting transformer is connected with a terminal corresponding to a fault in the terminals led out from the secondary side, and the other terminal of the low-voltage side of the boosting transformer is connected with a corresponding terminal leading out of the terminals led out from the secondary side by 120 degrees ahead of the fault phase;
if the wiring mode of the Z-type grounding transformer is ZNY1, one terminal of the low-voltage side of the boosting transformer is connected with a terminal corresponding to a fault in the terminals led out from the secondary side, and the other terminal is connected with a corresponding terminal lagging by 120 degrees for a fault phase in the terminals led out from the secondary side.
Further preferably, the terminals of two wires led out from each of the three phases of the secondary side A, B, C of the Z-type grounding transformer form two groups of terminals, each group of terminals includes three terminals, and the three terminals respectively correspond to the A, B, C three phases;
the two terminals on one side of the voltage regulator respectively correspond to one group of terminals and are respectively selectively connected in the corresponding group of terminals.
In a second aspect, the present invention provides a single-phase earth fault current full compensation device for a power distribution network, including: the Z-type grounding transformer is connected to a power distribution network, the tail ends of phase-shifting windings of the Z-type grounding transformer are connected in a star mode to form a neutral point O, and terminals of A, B, C three-phase lead-out wires on the secondary side are connected selectively with terminals on one side of the boosting transformer, one end of the high-voltage side of the boosting transformer is electrically connected with the neutral point O, and the other end of the high-voltage side of the boosting transformer is connected with the ground end;
when the fault is extinguished, two terminals on one side of the voltage regulator are respectively connected with 2 terminals led out from the secondary side of the Z-shaped grounding transformer to obtain voltage opposite to the voltage of a neutral point relative to the fault, and the voltage of the fault phase is boosted by the booster to be suppressed below the arc extinguishing voltage.
More preferably, the turn ratio of the primary side and the secondary side of the Z-type grounding transformer is N1:N2The high-voltage side of the step-up transformer is provided with n gears and the high-voltage side is provided with a voltage-regulating tapping tap KCThe boosting transformer is initially provided with a voltage-regulating tapping tap KCIn the gear n, the transformation ratio of the initial state is
When voltage regulating tapping tap KCAt the gear i, the transformation ratio of the boosting transformer is
i is a positive integer; the voltage-regulating tapping tap KCWith said protection tap KBIn parallel, the protection tap KBWith protective resistor, the voltage-regulating tap KCAnd said protection tap KBAre all connected in series with a switch S, and the switch S controls the on-off of the high-voltage side and the neutral point O.
Further preferably, when the wiring mode of the Z-type grounding transformer is ZNY11 during fault extinction, one terminal on the low-voltage side of the step-up transformer is connected to a terminal corresponding to a fault in the secondary-side lead-out terminals, and the other terminal is connected to a terminal corresponding to a fault phase advanced by 120 ° in the secondary-side lead-out terminals;
if the connection mode of the Z-type grounding transformer is ZNY1, one terminal of the low-voltage side of the step-up transformer is connected with a terminal corresponding to a fault in the terminals led out from the secondary side, and the other terminal is connected with a corresponding terminal lagging by 120 degrees for a fault phase in the terminals led out from the secondary side.
Advantageous effects
According to the method provided by the invention, the Z-shaped grounding transformer and the boosting transformer are connected into the re-distribution network, and the voltage opposite to the neutral point voltage of the fault is generated by utilizing the connection of the Z-shaped grounding transformer and the boosting transformer, wherein the voltage of the fault phase can be restrained below the arc quenching voltage after being boosted by utilizing the boosting transformer, so that the full compensation of the grounding current is realized. Because the voltage applied by the invention is taken from the power distribution network through the transformer, the phase position and the amplitude value of the three-phase voltage of the power distribution network can be strictly kept consistent, the voltage is controlled without setting a complex control method for calculating the current injected into a neutral point, and an independent power supply is not required to be added for supplying power, so that the invention can also be used in a system with larger ground capacitance of the power distribution network.
Drawings
Fig. 1 is a schematic wiring diagram of a single-phase earth fault current full-compensation principle of a power distribution network according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for fully compensating the single-phase earth fault current of the power distribution network according to the embodiment of the present invention.
Detailed Description
The present invention will be further described with reference to the following examples.
Example 1:
the wiring of the single-phase earth fault current full compensation principle of the power distribution network is shown in figure 1, and the embodiment of the invention realizes the compensation by utilizing the self-powered and uninterrupted power regulation and press fit of the high-voltage side of the step-up transformer.
For distribution network A, B, C three-phase voltage to earth, g is distribution network earth-to-earth conductance, C is distribution network earth-to-earth capacitance, RfTo transition resistance, YnIn order to allow the neutral point to be grounded,
are respectively the three-phase current of the power distribution network,
for fault currents, O is the neutral point, T1Is a Z-type grounding transformer, has a wiring form of ZNY1, and has a primary side and a secondary side transformation ratio of N1:N2The primary side of the Z-type grounding transformer is formed by reversely connecting coils with the same number of turns and the same winding direction in series, and the tail ends of the phase-shifting windings are connected in star to form a neutral point O, kx1、kx2(x ═ a, b, c) are respectively the switches led out from the three phases of the low voltage side A, B, C of the Z-type grounding transformer,
a, B, C three-phase voltage of a Z-type grounding transformer phase-shifting winding,
a, B, C three-phase voltage, T, output by the secondary side of the Z-type grounding transformer2For step-up transformer, the high-voltage side of step-up transformer has voltage-regulating tap KCAnd protection tapping KBN gears are uniformly arranged on the high-voltage side, are respectively 1, … and n, and when a voltage-regulating tap K is tappedCAt the gear i, the transformation ratio of the boosting transformer is
i is a positive integer. If n is set to 3, that is, if 3 shift stages are shift stages 1, 2, and 3, the transformation ratio of the corresponding step-up transformer is set to 3
And S is a switch between the step-up transformer and the neutral point O. RBTapping K for protectionBWith protective resistance against KCAnd KBAnd when the secondary side of the step-up transformer is connected, the short circuit occurs, and the switch is burnt.
Based on the circuit connection, the voltages of the windings in the Z-type grounding transformer have the following relationship:
the voltages of the three phases of the power distribution network to the neutral point O are respectively as follows:
wherein,
three-phase to neutral point voltages of the power distribution network are respectively;
is a directional operator, indicating 30 ° counterclockwise rotation;
respectively represents the three-phase power electromotive force of the power distribution network, the three are equal in size,
advance in
Hysteresis
Based on the terminal led out from the low-voltage side A, B, C of the Z-shaped grounding transformer, a step-up transformer T2Connection modes with the Z-type grounding transformer exist: k is a radical ofb1+ka2、kc1+kb2And ka1+kc2. Therefore, the three-phase outgoing switch k of the low-voltage side A, B, C of the Z-shaped grounding transformer is respectively closedx1And ky2At this time, the step-up transformer T2Voltage of low voltage side
Respectively as follows:
after the switch S is closed, when the voltage regulating tapping tap KCWhen the gear is at the gear n, the switch in the formula (4) is closed, and the corresponding neutral point is grounded
Respectively as follows:
if the C phase of the power distribution network has a single-phase earth fault, the current of a fault point is as follows:
at this time, switch k is first closeda1、kc2Then switch S is closed, C is at ground relative voltage:
the united type (6) and the united type (7) can be obtained, the current of the fault point is 0, and the full compensation of the fault current is realized.
Similarly, when a single-phase earth fault occurs in phase a, switch k is first closedb1、ka2Then, the switch S is closed, and the fault current full compensation can be realized; when a single-phase earth fault occurs in the B phase, the switch k is firstly closedc1、kb2And then the switch S is closed, so that the fault current full compensation can be realized. In summary, when the wiring form of the Z-type grounding transformer is ZNY1, it closes the corresponding secondary side switch k of the Z-type grounding transformer according to the fault phasex1And ky2Where y is the phase corresponding to the fault and x is the phase corresponding to the 120 deg. lagging fault phase.
It should be understood that in other possible embodiments, if the wiring form of the Z-type grounding transformer is ZNY11, the corresponding Z-type grounding transformer secondary side switch k is closed according to the fault phasex1And ky2Where y is the phase corresponding to the fault and x is the phase corresponding to the leading fault phase by 120 deg.. Other possible embodiments are not limited to the secondary side A, B, C of the Z-type grounding transformer with 2 sets of terminals, for example, 1 or more sets, can implement the concepts of the present invention.
After the fault current is fully compensated and is delayed for a certain time t, the neutral point voltage is gradually changed, whether the fault disappears or not is judged, whether the original states of the switches and the gears are recovered or not is determined, and the normal operation of the power distribution network is recovered. In this embodiment, the method of changing the neutral point voltage is as follows:
firstly, a protection tapping tap K is adjustedBTap K for tapping with voltage regulationCThe gears connected are consistent; then changing voltage-regulating tapping tap KCSubtracting 1 from the connected gear; finally disconnecting protection tapping KBThe step-up transformer is connected with the high-voltage side gears, and the zero sequence current of the power distribution network is recorded; repeating the above steps until KCThe gear connected is gear 1, and the recorded zero sequence electricity of the power distribution network is comparedWhether the current effective value and the zero sequence voltage meet the linear relation or not.
1) If the line type change is satisfied, the fault is judged to disappear, the switch S is disconnected firstly, and then the voltage-regulating tapping tap K is recoveredCTapping K for protection tappingBInitial position, finally opening switch ka1、kc2The power distribution network recovers normal operation;
2) if the linear change is not satisfied, the fault is judged to still exist, and a protection tapping tap K is adjustedBTo gear 1, then changing a voltage-regulating tap KCTo a gear n, finally disconnecting a protection tapping tap KBAnd the connection with the high-voltage side of the step-up transformer keeps the fault current fully compensated and waits for fault treatment.
Zero sequence current in power distribution network fault
Comprises the following steps:
in the formula,ωrepresenting angular frequency at 50Hz, j representing imaginary symbol, and (3) - (5), (8) obtaining tap K when regulating voltageCEffective value I of zero sequence current of power distribution network when fault exists and is positioned on gear I0iComprises the following steps:
wherein i is a voltage-regulating tap KCThe current gear.
Zero sequence current after power distribution network fault disappears
Comprises the following steps:
the combined vertical type (3) - (5) and (10) obtain a voltage-regulating tapping tap KCThe zero sequence current effective value I of the power distribution network is positioned on the gear I and after the fault disappears0iComprises the following steps:
as can be seen from the formulas (9) and (11), when the power distribution network fault exists, the effective value of the zero sequence current of the power distribution network is tapped with the tap K along with the voltage regulationCThe gears are in nonlinear change; when the fault of the power distribution network disappears, the effective value of the zero sequence current of the power distribution network is tapped with tap K along with the voltage regulationCThe gears are changed in a linear mode.
The fact that the zero-sequence current of the power distribution network changes linearly along with the change of the gear of the voltage-regulating tap-off tap means that when the absolute value | r | of the correlation coefficient between the zero-sequence current and the gear of the voltage-regulating tap-off is larger than or equal to a preset threshold value, the zero-sequence current changes linearly along with the voltage-regulating tap-off KCThe change of the gear is linear. In this embodiment, the preset threshold is 0.99.
The absolute value | r | of the correlation coefficient between the zero-sequence current and the gear position of the voltage-regulating tap is obtained by adopting the following formula:
in the formula: i is a voltage-regulating tap KCIn the gear position of0iThe value of the zero sequence current of the power distribution network of the line at the ith gear is shown, and n represents the total gear amount of the high-voltage side of the step-up transformer.
According to the analysis, the provided fault current full compensation method can effectively reduce the fault point current to 0, the zero sequence voltage applied to the neutral point does not need to be additionally provided with a power electronic inverter, and the capacity of the power distribution network does not influence the fault current full compensation method; in the fault disappearance judgment process, the neutral point always has the external zero sequence voltage, and the sudden increase of the fault current caused by the sudden loss of the external voltage of the neutral point can be avoided.
Based on the above principle description, a flowchart of a method for fully compensating for a single-phase earth fault current of a power distribution network according to an embodiment of the present invention is shown in fig. 2, and the method includes the following specific steps:
1) closing corresponding secondary side switch k of Z-shaped grounding transformer according to fault phasex1And ky2Where y is the phase corresponding to the fault and x is the phase corresponding to the 120 ° lagging fault phase;
2) closing the switch S;
3) delaying a certain time t, wherein the time t is generally selected as an empirical value, namely, the time t is set according to actual requirements and conditions;
4) regulating protection tapping tap KBTap K for tapping with voltage regulationCThe gears connected are consistent;
5) reducing the gear positions connected with the 1 voltage-regulating tapping tap;
6) disconnection protection tapping KBRecording the zero sequence current I of the power distribution network at the moment0i；
7) Repeating the steps 4) to 6) until KBThe engaged gear is 1.
8) Calculating the absolute value | r | of the correlation coefficient of the zero-sequence current and the gear of the voltage-regulating tapping tap according to the formula (12);
9) if the | r | > is more than or equal to 0.99, the switch S is disconnected, and the switches and the tapping taps are restored to the original state;
10) if r < 0.99, the tapped tap is restored to the original state.
In some embodiments, the step 1) is performed such that the faulted phase voltage is suppressed below the arc-quenching voltage.
In some embodiments, other step-up transformers with adjustable transformation ratios may be selected.
To sum up, in this embodiment, only need can realize the fault current full compensation when the different phases break down through closing different switches, and Z type grounding transformer has equipment for the transformer substation, only needs to increase a single-phase step-up transformer and the gear that corresponds takes a percentage, has reduced investment cost greatly, has very strong economic nature. When the gear is changed to judge whether the fault disappears, the neutral point is always provided with an external power supply, and the fault current cannot be suddenly increased.
It should be emphasized that the examples described herein are illustrative and not restrictive, and thus the invention is not to be limited to the examples described herein, but rather to other embodiments that may be devised by those skilled in the art based on the teachings herein, and that various modifications, alterations, and substitutions are possible without departing from the spirit and scope of the present invention.
Claims (10)
1. A power distribution network single-phase earth fault current full compensation method is characterized by comprising the following steps: the method comprises the following steps: s1: two terminals on one side of a step-up transformer are respectively connected with 2 terminals led out from the secondary side of a Z-shaped grounding transformer to obtain voltage opposite to the voltage of a neutral point relative to a fault, and the voltage of the fault phase is restrained below arc quenching voltage after being boosted by the step-up transformer;
the Z-type grounding transformer is connected to a power distribution network, the tail ends of phase-shifting windings of the Z-type grounding transformer are connected in a star mode to form a neutral point O, terminals of a secondary side A, B, C three-phase lead-out wiring terminal are formed, the terminals led out of the secondary side are used for selectively connecting terminals of a low-voltage side of the booster transformer, one end of a high-voltage side of the booster transformer is electrically connected with the neutral point O, and the other end of the high-voltage side of the booster transformer is connected.
2. The method of claim 1, wherein: the transformation ratio of the Z-shaped grounding transformer is N1:N2The high-voltage side of the step-up transformer is provided with n gears and the high-voltage side is provided with a voltage-regulating tapping tap KCThe boosting transformer is initially provided with a voltage-regulating tapping tap KCIn the gear n, the transformation ratio of the initial state is
When voltage regulating tapping tap KCAt the gear i, the transformation ratio of the boosting transformer is
i is a positive integer; and after the step S1 is executed, the method further comprisesThe method comprises the following steps:
s2: delaying for a preset time t;
s3: based on adjust pressure regulating tapping KCContinuously changing the transformation ratio of the boosting transformer in the connected gear, and recording the zero sequence current of the power distribution network after the transformation ratio is changed each time;
wherein if the zero sequence current follows the voltage-regulating tapping tap KCThe change of the connected gear is nonlinear change, and the fault does not disappear; if the zero sequence current follows the voltage-regulating tapping tap KCThe change of the connected gear is linear change, and the fault disappears.
3. The method of claim 2, wherein: tap K for judging zero sequence current along with voltage regulationCWhether the change of the connected gear is linear or not is determined by zero sequence current and the voltage-regulating tap KCWhether the absolute value of the correlation coefficient of the gear is larger than or equal to a preset threshold value or not, and if the absolute value of the correlation coefficient of the gear is larger than or equal to the preset threshold value, the absolute value changes linearly; otherwise, the change is nonlinear.
4. The method of claim 3, wherein: the calculation formula of the correlation coefficient is as follows:
where r represents a correlation coefficient and i represents the voltage regulation tap KCThe connected gear is that I is more than or equal to 1 and less than or equal to n, I0iIndicating said voltage regulating tap KCZero sequence current I of power distribution network in connected gear I0。
5. The method of claim 2, wherein: the high-voltage side of the step-up transformer is also provided with a tap K for tapping the voltage for regulatingCParallel protection tapping KBSaid protection tap KBWith protective resistor, the voltage-regulating tap KCAnd said protection tap KBAre all connected in series with a switch S, and the switch S controls the on-off of the high-voltage side and the neutral point O.
6. The method of claim 5, wherein: adjusting the voltage-regulating tap KCIn the process of gear shifting, the voltage-regulating tap K is changedCWhen the gear is connected, the protection tapping joint KBThe high-pressure side gear is switched on; waiting for the voltage-regulating tapping tap KCAfter connection, the protective tapping tap K is disconnectedBThe zero sequence current of the power distribution network is recorded by connecting with a high-voltage side gear, and the voltage regulating tapping tap K is sequentially regulated by repeating the stepsCThe connection with a high-pressure side gear;
if the fault has disappeared, the switch S is disconnected and the voltage-regulating tap K is restoredCAnd said protection tap KBTo n-gear, and disconnecting the boosting transformer from the Z-type grounding transformer;
if the fault does not disappear, the voltage regulating tapping tap K is adjustedCConnecting with n gear, and disconnecting the protective tapping joint KBAnd the connection with the high-pressure side gear waits for fault processing.
7. The method of claim 1, wherein: when the fault is extinguished, the connection between the boosting transformer and the Z-shaped grounding transformer is as follows: if the wiring mode of the Z-shaped grounding transformer is ZNY11, one terminal of the low-voltage side of the boosting transformer is connected with a terminal corresponding to a fault in the terminals led out from the secondary side, and the other terminal of the low-voltage side of the boosting transformer is connected with a corresponding terminal leading out of the terminals led out from the secondary side by 120 degrees ahead of the fault phase;
if the wiring mode of the Z-type grounding transformer is ZNY1, one terminal of the low-voltage side of the boosting transformer is connected with a terminal corresponding to a fault in the terminals led out from the secondary side, and the other terminal is connected with a corresponding terminal lagging by 120 degrees for a fault phase in the terminals led out from the secondary side.
8. The utility model provides a full compensation arrangement of distribution network single-phase earth fault current which characterized in that: the method comprises the following steps: the Z-type grounding transformer is connected to a power distribution network, the tail ends of phase-shifting windings of the Z-type grounding transformer are connected in a star mode to form a neutral point O, and terminals of A, B, C three-phase lead-out wires on the secondary side are connected selectively with terminals on one side of the boosting transformer, one end of the high-voltage side of the boosting transformer is electrically connected with the neutral point O, and the other end of the high-voltage side of the boosting transformer is connected with the ground end;
when the fault is extinguished, two terminals on one side of the voltage regulator are respectively connected with 2 terminals led out from the secondary side of the Z-shaped grounding transformer to obtain voltage opposite to the voltage of a neutral point relative to the fault, and the voltage of the fault phase is boosted by the booster to be suppressed below the arc extinguishing voltage.
9. The apparatus of claim 8, wherein: the turn ratio of the primary side and the secondary side of the Z-shaped grounding transformer is N1:N2The transformation ratio of the step-up transformer is
Step-up transformer's high-pressure side sets up n gears and high-pressure side is equipped with voltage regulation shunting and takes a percentage KCAnd protection tapping KBWhen the voltage is adjusted, the tapping tap KCWhen the step-up transformer is in a gear i, the turn ratio of the step-up transformer is equal to
i is a positive integer; the voltage-regulating tapping tap KCWith said protection tap KBIn parallel, the protection tap KBWith protective resistor, the voltage-regulating tap KCAnd said protection tap KBAre all connected in series with a switch S, and the switch S controls the on-off of the high-voltage side and the neutral point O.
10. The apparatus of claim 8, wherein: when the fault arc is extinguished, if the wiring mode of the Z-shaped grounding transformer is ZNY11, one terminal on the low-voltage side of the boosting transformer is connected with a terminal corresponding to the fault in the terminals led out from the secondary side, and the other terminal is connected with a corresponding terminal leading out from the terminals led out from the secondary side by 120 degrees ahead of the fault phase;
if the connection mode of the Z-type grounding transformer is ZNY1, one terminal of the low-voltage side of the step-up transformer is connected with a terminal corresponding to a fault in the terminals led out from the secondary side, and the other terminal is connected with a corresponding terminal lagging by 120 degrees for a fault phase in the terminals led out from the secondary side.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115693630A (en) * | 2023-01-05 | 2023-02-03 | 国网山西省电力公司朔州供电公司 | Mixed arc quenching system based on split winding and working method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101212138A (en) * | 2006-12-25 | 2008-07-02 | 万达集团股份有限公司 | Capacitance-adjustable automatic compensating arc extinguishing coil |
| CN107276097A (en) * | 2017-07-05 | 2017-10-20 | 长沙理工大学 | Non-effectively earthed system earth fault is mutually depressured the method for safe operation of extinguishing arc |
| EP3506445A1 (en) * | 2017-12-27 | 2019-07-03 | ABB Schweiz AG | System for identification of a feeder with high-ohmic earth fault in a distribution network |
| WO2020087811A1 (en) * | 2018-11-01 | 2020-05-07 | 杭州求创电力科技有限公司 | Method for suppressing fault phase residual voltage of resonant grounding system based on precise tuning control on active adjustable complex impedance |
| CN111262231A (en) * | 2019-12-24 | 2020-06-09 | 长沙理工大学 | Non-effective grounding system grounding arc suppression device, method, equipment and medium |
| CN111697552A (en) * | 2020-06-08 | 2020-09-22 | 上海交通大学 | Voltage regulator-based arc suppression coil automatic tuning method and device |
-
2021
- 2021-01-18 CN CN202110059562.3A patent/CN112909912B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101212138A (en) * | 2006-12-25 | 2008-07-02 | 万达集团股份有限公司 | Capacitance-adjustable automatic compensating arc extinguishing coil |
| CN107276097A (en) * | 2017-07-05 | 2017-10-20 | 长沙理工大学 | Non-effectively earthed system earth fault is mutually depressured the method for safe operation of extinguishing arc |
| EP3506445A1 (en) * | 2017-12-27 | 2019-07-03 | ABB Schweiz AG | System for identification of a feeder with high-ohmic earth fault in a distribution network |
| WO2020087811A1 (en) * | 2018-11-01 | 2020-05-07 | 杭州求创电力科技有限公司 | Method for suppressing fault phase residual voltage of resonant grounding system based on precise tuning control on active adjustable complex impedance |
| CN111262231A (en) * | 2019-12-24 | 2020-06-09 | 长沙理工大学 | Non-effective grounding system grounding arc suppression device, method, equipment and medium |
| CN111697552A (en) * | 2020-06-08 | 2020-09-22 | 上海交通大学 | Voltage regulator-based arc suppression coil automatic tuning method and device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115693630A (en) * | 2023-01-05 | 2023-02-03 | 国网山西省电力公司朔州供电公司 | Mixed arc quenching system based on split winding and working method thereof |
| CN115693630B (en) * | 2023-01-05 | 2023-04-25 | 国网山西省电力公司朔州供电公司 | Hybrid arc extinguishing system based on split winding and working method thereof |
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