CN110148931B - Arc suppression coil parallel low-resistance grounding device and control method - Google Patents
Arc suppression coil parallel low-resistance grounding device and control method Download PDFInfo
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- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
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Abstract
The invention discloses an arc suppression coil parallel low-resistance grounding device and a control method, wherein the device comprises: the device comprises an arc suppression coil device, a grounding transformer, a low-resistance grounding resistor, a low-resistance fling-cut switch and a controller; the three-phase input end of the grounding transformer is connected with a power grid, and the output end of the grounding transformer is connected with the input end of the arc suppression coil device and the first end of the low-resistance fling-cut switch; the second end of the low-resistance switching switch is connected with the first end of the low-resistance grounding resistor; the output end of the arc suppression coil device and the second end of the low-resistance grounding resistor are grounded; the controller is connected with the control end of the low-resistance switching switch and used for identifying the fault point transition resistance and the transition resistance, controlling the switching of the low-resistance grounding resistor and controlling the compensation of the arc suppression coil according to the fault point transition resistance and the critical transition resistance; through discerning fault point transition resistance, whether control low resistance earth resistor throw-in again can realize the low resistance function of many times throw-in and throw-in again, satisfies actual fault operating mode requirement.
Description
Technical Field
The invention relates to the technical field of arc suppression coil parallel low-resistance grounding, in particular to an arc suppression coil parallel low-resistance grounding device and a control method.
Background
In the power system, the neutral grounding mode is selected according to the insulation level of the power grid equipment and the magnitude of the capacitance current. For a power distribution network mainly comprising an overhead line, a neutral point is grounded through an arc suppression coil; for an urban power distribution network mainly based on cable lines, the single-phase earth fault has large capacitance and current, and a mode that a neutral point is grounded through a small resistor is mostly adopted. However, the neutral point is grounded through an arc suppression coil, which brings certain difficulty to permanent fault line selection and is difficult to rapidly and accurately remove faults; the neutral point can not distinguish instantaneous earth faults from permanent earth faults in a small-resistance earthing mode, and line tripping is started for all single-phase earthing, so that the line tripping times are increased, and the power supply reliability is influenced. The flexible grounding mode of connecting the arc suppression coil with the small resistor in parallel can be combined with the advantages of eliminating transient faults and quickly isolating permanent faults by the arc suppression coil, the problems of the arc suppression coil and the small resistor are solved, and the power supply safety and reliability of the power distribution network are greatly improved. At present, the flexible grounding control device with arc suppression coils connected with small resistors in parallel is developed successfully, is tried out in China generally, and achieves a good effect.
However, at present, the working principle of the arc suppression coil parallel low-resistance grounding device is still deficient, mainly, if the fault does not disappear after the low-resistance grounding resistor is put into use, the arc suppression coil continues to compensate for a certain time (generally less than 2h), and if the fault point range is enlarged or the fault point grounding transition resistance is reduced within the compensation time range, the arc suppression coil parallel low-resistance grounding device is not put into the low-resistance grounding resistor again to isolate the fault, and the actual fault working condition cannot be processed.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide an arc suppression coil parallel low-resistance grounding device and a control method thereof, which can realize multiple switching low-resistance functions and meet the requirements of actual fault conditions.
In a first aspect, an embodiment of the present invention provides an arc suppression coil parallel low-resistance grounding device, including: the device comprises an arc suppression coil device, a grounding transformer, a low-resistance grounding resistor, a low-resistance fling-cut switch and a controller; the three-phase input end of the grounding transformer is used for being connected into a power grid, and the output end of the grounding transformer is connected with the input end of the arc suppression coil device and the first end of the low-resistance switching switch; the second end of the low-resistance switching switch is connected with the first end of the low-resistance grounding resistor; the output end of the arc suppression coil device and the second end of the low-resistance grounding resistor are grounded; the controller is connected with the control end of the low-resistance switching switch and used for identifying fault point transition resistance and critical transition resistance, controlling switching of the low-resistance grounding resistor and controlling the arc suppression coil to compensate according to the fault point transition resistance and the critical transition resistance.
Preferably, the grounding transformer is a Y-connected three-winding transformer, wherein a neutral point of the grounding transformer is connected with an input end of the arc suppression coil device.
Preferably, the arc suppression coil parallel low-resistance grounding device further comprises a first voltage transformer and a second voltage transformer which are connected with the controller; the first voltage transformer is used for being connected to a power grid bus and measuring phase voltage of a single-phase earth fault phase; the second voltage transformer is connected between the neutral point of the grounding transformer and the input end of the arc suppression coil device and used for detecting the voltage at the neutral point of the grounding transformer.
Preferably, the arc suppression coil parallel low-resistance grounding device further comprises a current transformer connected with the controller, and the current transformer is connected to a branch of the arc suppression coil device and is used for detecting a compensation current when the arc suppression coil device compensates.
Compared with the prior art, the embodiment of the invention has the beneficial effects that:
the parallel low resistance earthing device of arc suppression coil includes: the device comprises an arc suppression coil device, a grounding transformer, a low-resistance grounding resistor, a low-resistance fling-cut switch and a controller; the three-phase input end of the grounding transformer is used for being connected into a power grid, and the output end of the grounding transformer is connected with the input end of the arc suppression coil device and the first end of the low-resistance switching switch; the second end of the low-resistance switching switch is connected with the first end of the low-resistance grounding resistor; the output end of the arc suppression coil device and the second end of the low-resistance grounding resistor are grounded; the controller is connected with the control end of the low-resistance switching switch and is used for identifying fault point transition resistance and transition resistance control and controlling switching of the low-resistance grounding resistor according to the fault point transition resistance and the critical transition resistance; through the fault point transition resistance and the transition resistance which are identified, whether the low-resistance grounding resistor is switched again or not is controlled, the function of switching the low resistance for many times can be realized, and the requirement of actual fault working conditions is met.
In a second aspect, an embodiment of the present invention provides a method for controlling a parallel low-resistance grounding device for a crowbar coil, which employs the parallel low-resistance grounding device for a crowbar coil according to any one of the first aspect, and includes the following steps:
the controller controls the low-resistance grounding resistor to be switched;
obtaining phase voltage detected by a first voltage transformer, voltage at a neutral point detected by a second voltage transformer and ground capacitance of a power grid outgoing line detected by an arc suppression coil device after the low-resistance grounding resistor is switched in;
acquiring compensation current detected by the current transformer after the low-resistance grounding resistor is withdrawn;
calculating a fault point transition resistance according to the phase voltage, the voltage at the neutral point, the compensation current and the capacitance to ground;
calculating a critical transition resistance according to a preset zero sequence protection setting value of the line, the voltage at a neutral point, the compensating current and the ground capacitance;
judging whether to switch the low-resistance grounding resistor again or not according to the fault point transition resistance and the critical transition resistance;
and when the transition resistance is not greater than the critical transition resistance, controlling the low-resistance grounding resistor to be switched again.
Preferably, the calculating a fault point transition resistance according to the phase voltage, the voltage at the neutral point, the compensation current and the capacitance to ground specifically includes:
calculating the inductance of the arc suppression coil according to the voltage and the compensation current at the neutral point;
calculating the zero sequence current of the fault line during the compensation period of the arc suppression coil according to the voltage, the compensation current and the capacitance to ground at the neutral point;
and calculating the transition resistance of the fault point according to the phase voltage, the inductance of the arc suppression coil, the zero sequence current of the fault line and the capacitance to the ground.
Preferably, the calculating a critical transition resistance according to a preset zero-sequence protection setting value of the line, a voltage at a neutral point, a compensation current and the ground capacitance specifically includes:
calculating a critical transition resistance according to formula (1);
wherein w 2 pi f 314rad/s, L is arc suppression coil inductance, C is the capacitance to ground, R is the resistance value of the low-resistance grounding resistor, IzFor a preset zero sequence protection setting value, U, of the linexThe phase voltage.
Preferably, the calculating the arc suppression coil inductance according to the voltage at the neutral point and the compensation current specifically includes:
calculating the inductance of the arc suppression coil according to the formula (2);
wherein, U0Is the voltage at the neutral point, ILTo compensate for the current.
Preferably, the calculating the zero sequence current of the fault line during the compensation of the arc suppression coil according to the voltage at the neutral point, the compensation current and the capacitance to ground specifically includes:
and (4) calculating the zero sequence current of the fault line during the compensation of the arc suppression coil according to the formula (3).
Preferably, the calculating a fault point transition resistance according to the phase voltage, the arc suppression coil inductance, the zero sequence current of the fault line, and the ground capacitance specifically includes:
and (4) calculating the transition resistance of the fault point according to the formula (4).
Compared with the prior art, the embodiment of the invention has the beneficial effects that:
the control method of the arc suppression coil parallel low-resistance grounding device monitors the transition resistance R of the fault point after the low-resistance grounding resistor is put into and withdrawnfAnd as fault point transition resistance RfLess than or equal to critical transition resistance RzThe device switches in the low-resistance grounding resistor again to cut off the fault line; transition resistance R at fault pointfCritical transition resistance RzThe device is not put into the low-resistance grounding resistor and is kept in the compensation state of the arc suppression coil, so that the problem that the traditional arc suppression coil parallel low-resistance grounding device cannot put into the low-resistance grounding resistor again to isolate faults when the range of fault points is enlarged or the grounding transition resistance of the fault points is reduced in the compensation time range can be avoided, and a fault circuit can be effectively cut off.
Drawings
In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic circuit diagram of a low-resistance grounding device connected in parallel with an arc suppression coil according to a first embodiment of the present invention;
fig. 2 is a flowchart of a control method of an arc suppression coil parallel low-resistance grounding device according to a second embodiment of the present invention;
FIG. 3 is a schematic diagram of a line fault;
FIG. 4 is an equivalent circuit diagram of a single-phase ground fault after the low-resistance grounding resistor is switched in;
fig. 5 is a circuit diagram of a single-phase ground fault equivalent circuit after the low-resistance grounding resistor is withdrawn.
Detailed Description
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.
Referring to fig. 1, a first embodiment of the present invention provides an arc suppression coil parallel low-resistance grounding device, including: the device comprises an arc suppression coil device L, a grounding transformer 1, a low-resistance grounding resistor R, a low-resistance fling-cut switch K and a controller 2; the three-phase input end of the grounding transformer 1 is used for being connected to a power grid, and the output end of the grounding transformer 1 is connected with the input end of the arc suppression coil device L and the first end of the low-resistance switching switch; the second end of the low-resistance switching switch is connected with the first end of the low-resistance grounding resistor R; the output end of the arc suppression coil device L and the second end of the low-resistance grounding resistor R are grounded; the controller 2 is connected with the control end of the low-resistance switching switch and used for identifying fault point transition resistance and critical transition resistance, controlling switching of the low-resistance grounding resistor R and controlling the arc suppression coil to compensate according to the fault point transition resistance and the critical transition resistance.
In an alternative embodiment, the grounding transformer 1 is a Y-connected three-winding transformer, wherein the neutral point of the grounding transformer 1 is connected to the input of the arc suppression coil arrangement L.
In an alternative embodiment, the arc suppression coil parallel low-resistance grounding device further comprises a first voltage transformer (not identified in the figure) and a second voltage transformer (not identified in the figure) which are connected with the controller 2; the first voltage transformer is used for being connected to a power grid bus and measuring phase voltage of a single-phase earth fault phase; the second voltage transformer is connected between the neutral point of the grounding transformer 1 and the input end of the arc suppression coil device L, and is used for detecting the voltage at the neutral point of the grounding transformer 1.
In an alternative embodiment, the arc suppression coil parallel low-resistance grounding device further comprises a current transformer (not identified in the figure) connected to the controller 2, and the current transformer is connected to a branch of the arc suppression coil device L and is used for detecting a compensation current when the arc suppression coil device L compensates.
Further, the arc suppression coil parallel low-resistance grounding device further comprises a display module (not identified in the figure) connected with the controller 2, and the display module is used for displaying a fault point transition resistance monitoring result.
After the single-phase earth fault occurs, if the fault is not eliminated after the low resistance is put into the device for the first time, in the subsequent arc suppression coil compensation process, the device determines whether to put into the low resistance again according to the fault point transition resistance monitoring result, and then dynamic fault identification and isolation are realized. The working principle of the arc suppression coil parallel low-resistance grounding device is as follows:
the arc suppression coil is connected with the low-resistance grounding device in parallel to start a fault point transition resistance monitoring and identifying function, if the fault point transition resistance is monitored to be smaller than or equal to a critical transition resistance, the low-resistance grounding resistor R is thrown again to increase the fault point grounding current to trigger the relay protection device to act, and if not, the compensation state of the arc suppression coil is kept continuously; and if the fault disappears, the arc suppression coil compensation state is exited.
Compared with the prior art, the embodiment of the invention has the beneficial effects that:
the parallel low resistance earthing device of arc suppression coil includes: the device comprises an arc suppression coil device L, a grounding transformer 1, a low-resistance grounding resistor R, a low-resistance fling-cut switch and a controller 2; the three-phase input end of the grounding transformer 1 is used for being connected to a power grid, and the output end of the grounding transformer 1 is connected with the input end of the arc suppression coil device L and the first end of the low-resistance switching switch; the second end of the low-resistance switching switch is connected with the first end of the low-resistance grounding resistor R; the output end of the arc suppression coil device L and the second end of the low-resistance grounding resistor R are grounded; the controller 2 is connected with the control end of the low-resistance switching switch and is used for identifying fault point transition resistance and transition resistance control and controlling switching of the low-resistance grounding resistor R according to the fault point transition resistance and the critical transition resistance; the controller 2 identifies the fault point transition resistance and the transition resistance by acquiring the phase voltage of the single-phase earth fault phase measured by the first voltage transformer, the voltage of the neutral point of the earth transformer 1 detected by the second voltage transformer, the compensation current when the arc suppression coil device L compensates, and controls whether the low-resistance earth resistor R is switched again or not when the fault point transition resistance is smaller than or equal to the critical transition resistance, so that the low-resistance function can be realized for switching for many times, and the requirement of the actual fault working condition is met.
Referring to fig. 2, a second embodiment of the present invention provides a method for controlling a parallel low-resistance grounding device for arc suppression coils, which employs the parallel low-resistance grounding device for arc suppression coils according to any one of the first aspect, and includes the following steps:
s11: the controller controls the low-resistance grounding resistor to be switched;
in the embodiment of the invention, the controller can be a computer, a mobile phone, a tablet computer, a notebook computer, an industrial personal computer or a server and other computing equipment, and the control method of the arc suppression coil parallel low-resistance grounding device can be integrated with the controller as one of the functional modules and executed by the controller. S12: obtaining phase voltage detected by a first voltage transformer, voltage at a neutral point detected by a second voltage transformer and ground capacitance of a power grid outgoing line detected by an arc suppression coil device after the low-resistance grounding resistor is switched in;
s13: acquiring compensation current detected by the current transformer after the low-resistance grounding resistor is withdrawn;
s14: calculating a fault point transition resistance according to the phase voltage, the voltage at the neutral point, the compensation current and the capacitance to ground;
s15: calculating a critical transition resistance according to a preset zero sequence protection setting value of the line, the voltage at a neutral point, the compensating current and the ground capacitance;
s16: judging whether to switch the low-resistance grounding resistor again or not according to the fault point transition resistance and the critical transition resistance;
s17: and when the transition resistance is not greater than the critical transition resistance, controlling the low-resistance grounding resistor to be switched again.
In the embodiment of the invention, the fault point transition resistance R is monitored after the low-resistance grounding resistor is switched on and switched offfAnd as fault point transition resistance RfLess than or equal to critical transition resistance RzThe device switches in the low-resistance grounding resistor again to cut off the fault line; transition resistance R at fault pointfCritical transition resistance RzThe device is not put into the low-resistance grounding resistor and is kept in the compensation state of the arc suppression coil, so that the problem that the traditional arc suppression coil parallel low-resistance grounding device cannot put into the low-resistance grounding resistor again to isolate faults when the range of fault points is enlarged or the grounding transition resistance of the fault points is reduced in the compensation time range can be avoided, and a fault circuit can be effectively cut off.
In an alternative embodiment, the calculating the fault point transition resistance according to the phase voltage, the voltage at the neutral point, the compensation current and the capacitance to ground specifically includes:
calculating the inductance of the arc suppression coil according to the voltage and the compensation current at the neutral point;
calculating the zero sequence current of the fault line during the compensation period of the arc suppression coil according to the voltage, the compensation current and the capacitance to ground at the neutral point;
and calculating the transition resistance of the fault point according to the phase voltage, the inductance of the arc suppression coil, the zero sequence current of the fault line and the capacitance to the ground.
Before detecting the resistance value of the fault point transition resistor, the principle of low resistance input isolation fault will be explained by combining the schematic diagram of single phase earth fault of the line under the arc suppression coil parallel low resistance grounding device shown in fig. 3 and the equivalent circuit diagram of single phase earth fault after low resistance input shown in fig. 4:
in fig. 3, U is a three-phase system power supply, asplr is an arc suppression coil parallel low-resistance grounding device, C is the ground capacitance of all outgoing lines, R isfA transition equivalent resistance being a fault point; when arc suppression coil is connected in parallel with low-resistance grounding deviceAfter the low resistance R is input, the equivalent circuit of the single-phase earth fault after the low resistance is input is obtained as shown in figure 4, wherein U is shown in the figurexA phase voltage for a phase with a single-phase ground fault; u shape0Is the voltage at the neutral point; u shapefIs the fault ground voltage.
Then the zero sequence current I on the fault line during the low resistance input period can be calculated according to the formula (I)fComprises the following steps:
where w is 2 π f, typically 314 rad/s. Supposing that the zero sequence protection setting value of the line is IzWhen I is presentf＜IzWhen the low-resistance grounding resistor is put into use, the fault cannot be isolated; from this, it can be known that if the low-resistance grounding resistor is put into operation to cut off the fault line, the zero-sequence current I on the fault line is obtained after the low-resistance grounding resistor is put into operationfThe zero sequence protection setting value of the line is greater than or equal to Iz. It can therefore be seen that the requirements for putting a low resistance grounding resistor and isolating the faulty line are:
wherein R iszSetting value I for zero sequence protection of corresponding linezCritical transition resistance of (1). Thus, if the fault line is not eliminated after the first plunge of the low resistance grounding resistor, only the device is required to be able to transition resistance R to ground fault pointfPerforming monitoring identification when R is monitoredf≤RzAnd then, the low-resistance grounding resistor is put in again, otherwise, the low-resistance grounding resistor is not put in, and the compensation state of the arc suppression coil is continuously kept.
In an optional embodiment, the calculating a critical transition resistance according to a preset zero-sequence protection setting value of the line, a voltage at a neutral point, a compensation current, and the ground capacitance specifically includes:
calculating a critical transition resistance according to formula (1);
wherein w 2 pi f 314rad/s, L is arc suppression coil inductance, C is the capacitance to ground, R is the resistance value of the low-resistance grounding resistor, IzFor a preset zero sequence protection setting value, U, of the linexThe phase voltage.
In an optional embodiment, the calculating the arc suppression coil inductance according to the voltage at the neutral point and the compensation current specifically includes:
calculating the inductance of the arc suppression coil according to the formula (2);
wherein, U0Is the voltage at the neutral point, ILTo compensate for the current.
Please refer to fig. 5, which is an equivalent circuit diagram of a single-phase ground fault after the low-resistance grounding resistor exits, wherein the calculating of the zero-sequence current of the fault line during the arc suppression coil compensation period according to the voltage at the neutral point, the compensation current, and the capacitance to ground specifically includes:
and (4) calculating the zero sequence current of the fault line during the compensation of the arc suppression coil according to the formula (3).
In an optional embodiment, the calculating a fault point transition resistance according to the phase voltage, the arc suppression coil inductance, the fault line zero sequence current, and the capacitance to ground specifically includes:
and (4) calculating the transition resistance of the fault point according to the formula (4).
Compared with the prior art, the embodiment of the invention has the beneficial effects that:
by monitoring the fault point transition resistance R after the low resistance grounding resistor is switched in and outfAnd as fault point transition resistance RfLess than or equal to critical transition resistance RzThe device switches in the low-resistance grounding resistor again to cut off the fault line; transition resistance R at fault pointfCritical transition resistance RzThe device is not put into the low-resistance grounding resistor and is kept in the compensation state of the arc suppression coil, so that the problem that the traditional arc suppression coil parallel low-resistance grounding device cannot put into the low-resistance grounding resistor again to isolate faults when the range of fault points is enlarged or the grounding transition resistance of the fault points is reduced in the compensation time range can be avoided, and a fault circuit can be effectively cut off.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (7)
1. The utility model provides an arc suppression coil low resistance earthing device that connects in parallel which characterized in that includes: the device comprises an arc suppression coil device, a grounding transformer, a low-resistance grounding resistor, a low-resistance fling-cut switch and a controller; the three-phase input end of the grounding transformer is used for being connected into a power grid, and the output end of the grounding transformer is connected with the input end of the arc suppression coil device and the first end of the low-resistance switching switch; the second end of the low-resistance switching switch is connected with the first end of the low-resistance grounding resistor; the output end of the arc suppression coil device and the second end of the low-resistance grounding resistor are grounded; the controller is connected with the control end of the low-resistance switching switch and is used for identifying fault point transition resistance and critical transition resistance, and controlling switching of the low-resistance grounding resistor and controlling the arc suppression coil to compensate according to the fault point transition resistance and the critical transition resistance;
the grounding transformer is a Y-type wiring three-winding transformer, wherein a neutral point of the grounding transformer is connected with an input end of the arc suppression coil device;
the arc suppression coil parallel low-resistance grounding device further comprises a first voltage transformer and a second voltage transformer which are connected with the controller; the first voltage transformer is used for being connected to a power grid bus and measuring phase voltage of a single-phase earth fault phase; the second voltage transformer is connected between the neutral point of the grounding transformer and the input end of the arc suppression coil device and used for detecting the voltage at the neutral point of the grounding transformer;
the arc suppression coil parallel low-resistance grounding device further comprises a current transformer connected with the controller, and the current transformer is connected to a branch of the arc suppression coil device and used for detecting compensation current during compensation of the arc suppression coil device.
2. A method for controlling a parallel low-resistance grounding device of a crowbar coil, which is characterized by using the parallel low-resistance grounding device of the crowbar coil as claimed in claim 1, comprising the steps of:
the controller controls the low-resistance grounding resistor to be switched;
obtaining phase voltage detected by a first voltage transformer, voltage at a neutral point detected by a second voltage transformer and ground capacitance of a power grid outgoing line detected by an arc suppression coil device after the low-resistance grounding resistor is switched in;
acquiring compensation current detected by the current transformer after the low-resistance grounding resistor is withdrawn;
calculating a fault point transition resistance according to the phase voltage, the voltage at the neutral point, the compensation current and the capacitance to ground;
calculating a critical transition resistance according to a preset zero sequence protection setting value of the line, the voltage at a neutral point, the compensating current and the ground capacitance;
judging whether to switch the low-resistance grounding resistor again or not according to the fault point transition resistance and the critical transition resistance;
and when the transition resistance is not greater than the critical transition resistance, controlling the low-resistance grounding resistor to be switched again.
3. The method for controlling an arc suppression coil parallel low-resistance grounding device according to claim 2, wherein the calculating of the fault point transition resistance according to the phase voltage, the voltage at the neutral point, the compensation current and the capacitance to ground specifically comprises:
calculating the inductance of the arc suppression coil according to the voltage and the compensation current at the neutral point;
calculating the zero sequence current of the fault line during the compensation period of the arc suppression coil according to the voltage, the compensation current and the capacitance to ground at the neutral point;
and calculating the transition resistance of the fault point according to the phase voltage, the inductance of the arc suppression coil, the zero sequence current of the fault line and the capacitance to the ground.
4. The method for controlling an arc suppression coil parallel low-resistance grounding device according to claim 3, wherein the calculating of the critical transition resistance according to the preset zero-sequence protection setting value of the line, the voltage at the neutral point, the compensation current and the ground capacitance specifically comprises:
calculating a critical transition resistance according to formula (1);
wherein w 2 pi f 314rad/s, L is arc suppression coil inductance, C is the capacitance to ground, R is the resistance value of the low-resistance grounding resistor, IzFor a preset zero sequence protection setting value, U, of the linexThe phase voltage.
5. The method for controlling a parallel low-resistance grounding device of an arc suppression coil according to claim 4, wherein the calculating of the arc suppression coil inductance based on the neutral point voltage and the compensation current specifically comprises:
calculating the inductance of the arc suppression coil according to the formula (2);
wherein, U0Is the voltage at the neutral point, ILTo compensate for the current.
6. The method for controlling an arc suppression coil parallel low-resistance grounding device according to claim 5, wherein the step of calculating the zero-sequence current of the fault line during arc suppression coil compensation according to the voltage at the neutral point, the compensation current and the capacitance to ground specifically comprises the following steps:
calculating the zero sequence current of the fault line during the compensation of the arc suppression coil according to the formula (3);
7. the method for controlling an arc suppression coil parallel low-resistance grounding device according to claim 6, wherein the step of calculating the fault point transition resistance according to the phase voltage, the arc suppression coil inductance, the fault line zero sequence current and the ground capacitance specifically comprises the following steps:
calculating the transition resistance of the fault point according to a formula (4);
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| Publication number | Priority date | Publication date | Assignee | Title |
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| RO114520B1 (en) * | 1996-05-27 | 1999-04-30 | Renel Grupul De Studii Cerceta | Process and equipment for treating the grounding of medium-voltage networks |
| CN102545171A (en) * | 2011-12-22 | 2012-07-04 | 江苏宏安变压器有限公司 | Multi-winding adjustable reactor and single phase grounding fault clearing method thereof |
| CN203434624U (en) * | 2013-07-15 | 2014-02-12 | 国家电网公司 | 20kV flexible grounding control device |
| CN203522165U (en) * | 2013-11-04 | 2014-04-02 | 国家电网公司 | 20kV power distribution network neutral point grounding mode intelligent switching device |
| CN104092206A (en) * | 2014-06-20 | 2014-10-08 | 国家电网公司 | Power distribution network grounding self-adaptive control system and method |
| CN206533136U (en) * | 2016-12-20 | 2017-09-29 | 大连电力勘察设计院有限公司 | 220kV transformer stations arc suppression coil parallel low resistance earthed system |
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2019
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|---|---|---|---|---|
| RO114520B1 (en) * | 1996-05-27 | 1999-04-30 | Renel Grupul De Studii Cerceta | Process and equipment for treating the grounding of medium-voltage networks |
| CN102545171A (en) * | 2011-12-22 | 2012-07-04 | 江苏宏安变压器有限公司 | Multi-winding adjustable reactor and single phase grounding fault clearing method thereof |
| CN203434624U (en) * | 2013-07-15 | 2014-02-12 | 国家电网公司 | 20kV flexible grounding control device |
| CN203522165U (en) * | 2013-11-04 | 2014-04-02 | 国家电网公司 | 20kV power distribution network neutral point grounding mode intelligent switching device |
| CN104092206A (en) * | 2014-06-20 | 2014-10-08 | 国家电网公司 | Power distribution network grounding self-adaptive control system and method |
| CN206533136U (en) * | 2016-12-20 | 2017-09-29 | 大连电力勘察设计院有限公司 | 220kV transformer stations arc suppression coil parallel low resistance earthed system |
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