CN110912103A - Arc extinction method and device for single-phase earth fault admittance compensation voltage of power distribution network - Google Patents
Arc extinction method and device for single-phase earth fault admittance compensation voltage of power distribution network Download PDFInfo
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/08—Limitation or suppression of earth fault currents, e.g. Petersen coil
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Abstract
The invention discloses a power distribution network single-phase earth fault admittance compensation voltage arc extinction method, which comprises the steps that an independently adjustable inductance module is connected in parallel between each phase of a three-phase bus of a power system and a ground wire; adjusting the inductance module to a first initial value; real-time system voltage and inductor module current; when the zero sequence voltage variation is larger than a first set value, sequentially adjusting the inductance of each inductance module, measuring each relative admittance and three relative admittances, and pre-calculating a target reactance value of non-fault corresponding adjustment when each phase has a ground fault; when the zero sequence voltage variation is larger than a second set value, judging that a single-phase earth fault occurs, identifying a fault phase, and adjusting the inductance value of a non-fault phase to a target reactance value; and after the fault is eliminated, the inductance module is restored to the first initial value, and the power grid is restored to operate. The invention also discloses a device for realizing the arc extinction method of the single-phase earth fault admittance compensation voltage of the power distribution network. The invention has the advantages of easy implementation, high reliability, good practicability and quick response.
Description
Technical Field
The invention belongs to the field of electrical automation, and particularly relates to a method and a device for extinguishing arc of admittance compensation voltage of a single-phase earth fault of a power distribution network.
Background
With the development of economic technology and the improvement of living standard of people, electric energy becomes essential secondary energy in production and life of people, and brings endless convenience to production and life of people. Therefore, ensuring safe and stable operation of the system itself becomes one of the most important tasks of the power system.
The arc suppression coil is the most widely used arc suppression product of the present distribution network, and the product has simple and reliable structure and high response speed, but active components in fault current cannot be compensated, and personal safety accidents can be caused by voltage and current existing at fault points. The fast grounding switch realizes fault arc extinction by directly grounding the grounding fault phase in a metallic manner at a transformer substation, clamping the voltage of a fault phase bus and transferring fault point current, but the influence of the fast grounding switch under a low-resistance grounding fault by a line load is large, so that the fault point current is possibly increased. The active arc extinction compensation device realizes full compensation of fault current by injecting current with adjustable amplitude and phase angle into a system, but is not developed and applied on a large scale due to the restriction of the current power electronic technology.
Disclosure of Invention
The invention aims to provide a power distribution network single-phase earth fault admittance compensation voltage arc extinction method which is high in reliability, good in practicability and quick in response.
The invention also aims to provide a device for realizing the arc extinction method of the admittance compensation voltage of the single-phase earth fault of the power distribution network.
The invention provides an arc extinction method for admittance compensation voltage of a single-phase earth fault of a power distribution network, which comprises the following steps:
s1, an independently adjustable inductance module is connected in parallel between each phase of a three-phase bus of a power system and a ground wire;
s2, when the power grid normally runs, adjusting the inductance value of the inductance module in the step S1 to a first initial value to ensure that the power grid is far away from a resonance point when the power grid normally runs;
s3, monitoring system voltage of the power grid system and current signals flowing through each inductance module in real time;
s4, when the zero sequence voltage change quantity of the power grid system is monitored to be larger than a first set value, sequentially adjusting the inductance value of each inductance module in the step S1, measuring each relative ground admittance value and three relative ground admittance values of the power grid system, and meanwhile, pre-calculating a target reactance value which is adjusted correspondingly in a non-fault mode when each phase of the power grid system has a ground fault;
s5, when the zero sequence voltage change amount of the power grid system is monitored to be larger than a second set value, the power grid system is judged to have a single-phase earth fault at the moment, a fault phase is identified, and the inductance value of the inductance module connected with the non-fault phase is adjusted to the target reactance value calculated in the step S4, so that arc extinction is realized;
and S6, after the single-phase earth fault is determined to be eliminated, adjusting the inductance module to a first initial value, and recovering the operation of the power grid system.
Adjusting the inductance values of the inductor modules in step S1 in step S4, specifically, adjusting the inductance values of the inductor modules so that the value of the inductor is a phase voltage at which the shift voltage of the neutral point of the system does not exceed 15%.
Step S4, measuring each relative admittance value and the three relative admittance values of the power grid system, specifically calculating each relative admittance value and the three relative admittance values of the power grid system by using the following equations:
YΣ＝YA+YB+YC
in the formula YAIs the relative admittance value of A; y isBIs the relative admittance value of B; y isCIs the C three relative admittance value;
the voltage value of phase A relative to ground when phase A is thrown into the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase A is thrown into the inductance module;
the voltage value to ground of the phase C when the phase A is thrown into the inductance module;
the voltage to ground of the phase A of the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase B is thrown into the inductance module;
the voltage value to ground of the phase C when the phase B is thrown into the inductance module;
the voltage value to ground of the phase A is the voltage value to ground when the phase C is thrown into the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase C is thrown into the inductance module;
the voltage value to ground of the C phase is the voltage value to ground when the C phase is thrown into the inductance module;
the value of current flowing through the inductance element when the phase A is thrown into the inductance element;
the value of the current flowing through the inductance element when the phase B is thrown into the inductance element;
the current value of the C phase which flows through the inductance element when being thrown into the inductance element; y'AThe inductance variation is the admittance variation when the phase A independent inductance is adjusted; y'BThe inductance is the admittance change quantity when B phase independent inductance is adjusted; y'CThe inductance is the admittance change quantity when the C phase independent inductance is adjusted; y isΣIs the three relative admittance value.
Step S4, where the target reactance value adjusted correspondingly to the non-fault is calculated when each phase of the power grid system has an earth fault, specifically, the target reactance value adjusted correspondingly to the non-fault is calculated by using the following equation:
in the formula LLPA target inductance value for a lagging phase in a non-faulted phase; omega is the angular frequency of the power frequency of the system; cLPCapacitance value of lagging phase in non-fault phase; gAPThe conductance value of the leading phase in the non-fault phase; gLPThe conductance value of the lag phase in the non-fault phase; l isAPA target inductance value for a leading phase in a non-faulted phase; cAPThe capacitance value of the leading phase in the non-faulted phase.
The invention also provides a device for realizing the arc extinction method of the single-phase earth fault admittance compensation voltage of the power distribution network, which comprises a voltage measurement module, a current measurement module, a control module, an inductance module and a driving module; the voltage measuring module, the current measuring module and the driving module are all connected with the control module; the inductance module is connected with the driving module; the voltage measuring module is used for measuring the voltage of the power grid system and uploading the voltage to the control module; the current measuring module is used for measuring the current of the power grid system and uploading the current to the control module; the control module is used for calculating a target inductance value and sending a control signal to the driving module; the driving module is used for driving the inductance module to adjust the inductance value to a target value according to the received control signal.
The single-phase earth fault admittance compensation voltage arc extinction method and the single-phase earth fault admittance compensation voltage arc extinction device for the power distribution network adopt an inductance compensation method to realize single-phase earth fault arc extinction, and ensure personal and equipment safety of fault points; meanwhile, the invention can solve the capacity problem of the arc suppression coil grounding and the problem of incapability of compensating active components, solve the problem of incapability of effectively extinguishing the arc of the low-resistance grounding fault of the rapid transfer switch arc suppression device, and can solve the problem that the existing voltage arc suppression method can not completely compensate the single-phase grounding broken line fault; finally, the invention can utilize the existing mature equipment to realize the development of the arc extinction device, is easy to implement, and has high reliability, good practicability and quick response.
Drawings
FIG. 1 is a schematic process flow diagram of the process of the present invention.
FIG. 2 is a functional block diagram of the apparatus of the present invention.
Detailed Description
FIG. 1 is a schematic flow chart of the method of the present invention: the invention provides an arc extinction method for admittance compensation voltage of a single-phase earth fault of a power distribution network, which comprises the following steps:
s1, an independently adjustable inductance module is connected in parallel between each phase of a three-phase bus of a power system and a ground wire;
s2, when the power grid normally runs, adjusting the inductance value of the inductance module in the step S1 to a first initial value, so that the power grid is far away from a resonance point when the power grid normally runs;
s3, monitoring system voltage of the power grid system and current signals flowing through each inductance module in real time;
s4, when the zero sequence voltage change quantity of the power grid system is monitored to be larger than a first set value, sequentially adjusting the inductance value of each inductance module in the step S1, measuring each relative ground admittance value and three relative ground admittance values of the power grid system, and meanwhile, pre-calculating a target reactance value which is adjusted correspondingly in a non-fault mode when each phase of the power grid system has a ground fault;
in specific implementation, when the inductance value of the inductance module is adjusted, the value of the inductance enables the neutral point of the system to shift by no more than 15% of the phase voltage;
calculating each relative admittance value and the three relative admittance values of the power grid system by using the following equations:
YΣ＝YA+YB+YC
in the formula YAIs the relative admittance value of A; y isBIs the relative admittance value of B; y isCIs the C three relative admittance value;
the voltage value of phase A relative to ground when phase A is thrown into the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase A is thrown into the inductance module;
the voltage value to ground of the phase C when the phase A is thrown into the inductance module;
phase-to-ground voltage value of phase A when phase B is introduced into the inductance module；
The voltage value to ground of the phase B is the voltage value to ground when the phase B is thrown into the inductance module;
the voltage value to ground of the phase C when the phase B is thrown into the inductance module;
the voltage value to ground of the phase A is the voltage value to ground when the phase C is thrown into the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase C is thrown into the inductance module;
the voltage value to ground of the C phase is the voltage value to ground when the C phase is thrown into the inductance module;
the value of current flowing through the inductance element when the phase A is thrown into the inductance element;
the value of the current flowing through the inductance element when the phase B is thrown into the inductance element;
the current value of the C phase which flows through the inductance element when being thrown into the inductance element; y'AThe inductance variation is the admittance variation when the phase A independent inductance is adjusted; y'BThe inductance is the admittance change quantity when B phase independent inductance is adjusted; y'CThe inductance is the admittance change quantity when the C phase independent inductance is adjusted; y isΣIs the three relative admittance value;
and calculating a target reactance value which is not correspondingly adjusted in fault by adopting the following formula:
in the formula LLPA target inductance value for a lagging phase in a non-faulted phase; omega is the angular frequency of the power frequency of the system; cLPCapacitance value of lagging phase in non-fault phase; gAPThe conductance value of the leading phase in the non-fault phase; gLPThe conductance value of the lag phase in the non-fault phase; l isAPA target inductance value for a leading phase in a non-faulted phase; cAPThe capacitance value of the leading phase in the non-fault phase;
s5, when the zero sequence voltage change amount of the power grid system is monitored to be larger than a second set value, the power grid system is judged to have a single-phase earth fault at the moment, a fault phase is identified, and the inductance value of the inductance module connected with the non-fault phase is adjusted to the target reactance value calculated in the step S4, so that arc extinction is realized;
and S6, after the single-phase earth fault is determined to be eliminated, adjusting the inductance module to a first initial value, and recovering the operation of the power grid system.
FIG. 2 shows a functional block diagram of the apparatus of the present invention: the invention also provides a device for realizing the arc extinction method of the single-phase earth fault admittance compensation voltage of the power distribution network, which comprises a voltage measurement module, a current measurement module, a control module, an inductance module and a driving module; the voltage measuring module, the current measuring module and the driving module are all connected with the control module; the inductance module is connected with the driving module; the voltage measuring module is used for measuring the voltage of the power grid system and uploading the voltage to the control module; the current measuring module is used for measuring the current of the power grid system and uploading the current to the control module; the control module is used for calculating a target inductance value and sending a control signal to the driving module; the driving module is used for driving the inductance module to adjust the inductance value to a target value according to the received control signal.
Claims (5)
1. A power distribution network single-phase earth fault admittance compensation voltage arc extinction method comprises the following steps:
s1, an independently adjustable inductance module is connected in parallel between each phase of a three-phase bus of a power system and a ground wire;
s2, when the power grid normally runs, adjusting the inductance value of the inductance module in the step S1 to a first initial value, so that the power grid is far away from a resonance point when the power grid normally runs;
s3, monitoring system voltage of the power grid system and current signals flowing through each inductance module in real time;
s4, when the zero sequence voltage change quantity of the power grid system is monitored to be larger than a first set value, sequentially adjusting the inductance value of each inductance module in the step S1, measuring each relative ground admittance value and three relative ground admittance values of the power grid system, and meanwhile, pre-calculating a target reactance value which is adjusted correspondingly in a non-fault mode when each phase of the power grid system has a ground fault;
s5, when the zero sequence voltage change amount of the power grid system is monitored to be larger than a second set value, the power grid system is judged to have a single-phase earth fault at the moment, a fault phase is identified, and the inductance value of the inductance module connected with the non-fault phase is adjusted to the target reactance value calculated in the step S4, so that arc extinction is realized;
and S6, after the single-phase earth fault is determined to be eliminated, adjusting the inductance module to a first initial value, and recovering the operation of the power grid system.
2. The power distribution network single-phase ground fault admittance compensation voltage arc extinction method according to claim 1, wherein the inductance values of the respective inductance modules of the step S1 are adjusted in the step S4, specifically, the inductance values of the inductance modules are adjusted such that a shift voltage of a system neutral point does not exceed a phase voltage of 15%.
3. The method for arc extinction of a single-phase ground fault admittance compensation voltage of a power distribution network according to claim 2, wherein the step S4 is performed by measuring each relative admittance value and three relative admittance values of the power grid system, specifically calculating each relative admittance value and three relative admittance values of the power grid system by using the following equations:
YΣ＝YA+YB+YC
in the formula YAAdmittance of A to groundA value; y isBIs the relative admittance value of B; y isCIs the C three relative admittance value;
the voltage value of phase A relative to ground when phase A is thrown into the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase A is thrown into the inductance module;
the voltage value to ground of the phase C when the phase A is thrown into the inductance module;
the voltage value to ground of the phase A is the voltage value to ground when the phase B is thrown into the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase B is thrown into the inductance module;
the voltage value to ground of the phase C when the phase B is thrown into the inductance module;
the voltage value to ground of the phase A is the voltage value to ground when the phase C is thrown into the inductance module;
the voltage value to ground of the phase B is the voltage value to ground when the phase C is thrown into the inductance module;
the voltage value to ground of the C phase is the voltage value to ground when the C phase is thrown into the inductance module;
flowing through the inductor when A-phase is introduced into the inductorA current value of the element;
the value of the current flowing through the inductance element when the phase B is thrown into the inductance element;
the current value of the C phase which flows through the inductance element when being thrown into the inductance element; y'AThe inductance variation is the admittance variation when the phase A independent inductance is adjusted; y'BThe inductance is the admittance change quantity when B phase independent inductance is adjusted; y'CThe inductance is the admittance change quantity when the C phase independent inductance is adjusted; y isΣIs the three relative admittance value.
4. A method for suppressing an arc of a single-phase earth fault admittance compensation voltage of a power distribution network according to claim 3, wherein the step S4 is performed to calculate the target reactance value of the non-fault corresponding adjustment when an earth fault occurs in each phase of the power grid system, specifically, the target reactance value of the non-fault corresponding adjustment is calculated by using the following formula:
in the formula LLPA target inductance value for a lagging phase in a non-faulted phase; omega is the angular frequency of the power frequency of the system; cLPCapacitance value of lagging phase in non-fault phase; gAPThe conductance value of the leading phase in the non-fault phase; gLPThe conductance value of the lag phase in the non-fault phase; l isAPA target inductance value for a leading phase in a non-faulted phase; cAPThe capacitance value of the leading phase in the non-faulted phase.
5. An apparatus for implementing the power distribution network single-phase earth fault admittance compensation voltage arc extinction method according to any one of claims 1 to 4, wherein the apparatus comprises a voltage measurement module, a current measurement module, a control module, an inductance module and a driving module; the voltage measuring module, the current measuring module and the driving module are all connected with the control module; the inductance module is connected with the driving module; the voltage measuring module is used for measuring the voltage of the power grid system and uploading the voltage to the control module; the current measuring module is used for measuring the current of the power grid system and uploading the current to the control module; the control module is used for calculating a target inductance value and sending a control signal to the driving module; the driving module is used for driving the inductance module to adjust the inductance value to a target value according to the received control signal.
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