CN114977112A - Bidirectional converter direct current side short-circuit protection method based on rapid short-circuit current detection - Google Patents
Bidirectional converter direct current side short-circuit protection method based on rapid short-circuit current detection Download PDFInfo
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- CN114977112A CN114977112A CN202210617097.5A CN202210617097A CN114977112A CN 114977112 A CN114977112 A CN 114977112A CN 202210617097 A CN202210617097 A CN 202210617097A CN 114977112 A CN114977112 A CN 114977112A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- 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
- H02H7/10—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 for converters; for rectifiers
- H02H7/12—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 for converters; for rectifiers for static converters or rectifiers
- H02H7/122—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 for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
- H02H7/1227—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 for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters responsive to abnormalities in the output circuit, e.g. short circuit
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- 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
- H02H7/10—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 for converters; for rectifiers
- H02H7/12—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 for converters; for rectifiers for static converters or rectifiers
- H02H7/125—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 for converters; for rectifiers for static converters or rectifiers for rectifiers
- H02H7/1257—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 for converters; for rectifiers for static converters or rectifiers for rectifiers responsive to short circuit or wrong polarity in output circuit
Abstract
The invention discloses a rapid short-circuit current detection-based bidirectional converter direct current side short-circuit protection method, which is applied to short-circuit protection of a subway traction power supply bidirectional converter; a three-phase thyristor rectifier bridge circuit is arranged in the short-circuit protection device; the input end of the three-phase thyristor rectifier bridge circuit is connected to the direct current side of the bidirectional converter device, and the output end of the three-phase thyristor rectifier bridge circuit is connected to the output end of the inductor connected with the output end of the bidirectional converter device; the main control judges whether a short circuit of the inversion module, namely a near-end short circuit, or a far-end short circuit which is not the short circuit of the inversion module occurs according to the received voltage and current signals of the direct current side of the inversion module; according to the invention, the three-phase thyristor rectifier bridge circuit is connected in parallel with the inverter module, and when the inverter module is short-circuited, the open thyristor loop is switched on, so that the power unit of the bidirectional converter device can be reliably protected.
Description
Technical Field
The invention relates to the technical field of fault protection of urban rail transit power supply systems, in particular to a bidirectional converter direct-current side short-circuit protection method based on rapid short-circuit current detection.
Background
In recent years, urban rail transit has gradually become a daily choice for urban residents to live and go out, wherein an urban rail transit traction power supply system mainly provides a direct-current power supply for rail transit vehicles and other loads. With the continuous expansion of the urban rail transit road network scale, the higher departure density and the frequent train braking, the generated energy is continuously increased and accounts for about 20-40% of the energy of the traction power supply system.
At present, a rectifier unit configured in a rail transit system is 24-pulse uncontrolled rectification, and converts 35kV alternating current into direct current of a DC1500V grade through a rectifier transformer and a rectification module so as to provide a power supply for a load on a direct current traction contact network. The subway traction power supply bidirectional converter device can realize bidirectional flow of energy between a direct-current traction contact network and an alternating-current power grid, not only can provide energy for the direct-current traction contact network, support and stabilize the voltage of the direct-current traction contact network, but also can absorb redundant regenerative braking energy during train braking, feed back the redundant regenerative braking energy to the alternating-current power grid, and improve the energy utilization rate of a traction power supply system.
Meanwhile, the subway traction power supply bidirectional converter is required to have direct-current side short-circuit protection and overload protection, and is required to bear short-circuit current which is 20 times of rated current of the device for about 10ms and bear short-circuit current which is 12 times of rated current of the device for about 120 ms. When a traction direct current contact network has a short-circuit fault or runs in an overload mode, a 1500V switch cabinet direct current breaker of the currently configured traction network, a subway traction power supply bidirectional converter direct current contactor and the like are limited by breaking capacity and protection time, the breaking time is about 20ms, before the protection switch is disconnected, an anti-parallel diode of a three-phase IGBT module of a power module of the subway traction power supply bidirectional converter cannot bear large follow current, meanwhile, an alternating current system continuously provides current for a fault point on a direct current side through a three-phase uncontrolled rectifying circuit, the power module of the subway traction power supply bidirectional converter is damaged due to the fact that the current exceeds the tolerance current of the power module of the subway traction power supply bidirectional converter, and the device cannot normally run.
Therefore, the damage caused by short-circuit fault, overload and the like on the direct current side of the subway traction power supply bidirectional converter needs to be effectively avoided, the traction power supply bidirectional converter can rapidly quit operation when the fault occurs, meanwhile, the device can still maintain normal operation after the fault is removed, and the influence of short-circuit current and overload current on the device is effectively reduced.
In addition, the metro vehicle runs by taking electricity through a contact network (anode), large current can be generated in the acceleration and deceleration processes, and the overcurrent action threshold of the protection device on the feeder switch is often high in order to avoid frequent misoperation of the protection device on the feeder switch. Therefore, when a contact network (anode) is in a ground short-circuit fault through a large resistor, the fault current flowing through the feeder switch still can not reach the overcurrent action threshold, so that the protection device cannot act. Meanwhile, the ground resistance arranged on the negative bus of the traction substation causes a large potential difference between the ground and the negative bus of the traction substation due to the fault current flowing through the ground resistance, and causes simultaneous operation of leakage protection of voltage-type frames for preventing insulation damage of equipment in the plurality of traction substations, thereby causing large-area power failure of the traction power supply system.
At present, for the direct current side short circuit protection of a bidirectional conversion subway traction system, the prior art has the following three types:
the first prior art is as follows: patent document No. CN102707190A discloses a dc side short-circuit fault distance measuring device and method for a subway traction power supply system: each substation collects the current and voltage of the uplink and downlink contact networks on two sides of the substation, judges whether a short-circuit fault occurs according to the current, wirelessly transmits a current and voltage signal when the short-circuit fault occurs to an upper computer, and the upper computer further calculates the position of the short-circuit fault according to the received current and voltage signal. The short circuit detection provided by the method is based on current, only the near-end short circuit can be judged, and the far-end short circuit protection cannot be detected.
The second prior art is: the patent document with publication number CN112398103A discloses a protection method and device for a dc traction power supply system, which provides a protection method and system for a dc traction power supply system, wherein the protection device calculates a sum current in a traction power supply section according to acquired positive and negative feeder currents at two ends of the traction power supply section and the positive and negative feeder currents at the opposite ends of the dc traction power supply section, and when detecting that the sum current in the traction power supply section is greater than a set threshold value, the protection device determines that a contact network ground fault occurs in the traction power supply section, and trips off a positive feeder switch in the traction power supply section and an adjacent positive feeder switch. The short circuit detection method provided by the method also has the problems that only the near-end short circuit can be judged, and the far-end short circuit protection cannot be detected.
The prior art is three: the patent document with publication number CN 113644629a discloses a short-circuit protection device for a rail transit traction power supply bidirectional converter system and a control method thereof, wherein a control module obtains a direct current value at a direct current side of the bidirectional converter device, and determines whether the direct current value is greater than or equal to a direct current side overcurrent value preset by the control module, if the direct current value is greater than or equal to the direct current side overcurrent protection value, a pulse signal of a switch module and a pulse signal of a power module are blocked, so that the bidirectional converter system stops operating, and a short-circuit current is discharged to a low-voltage winding of an isolation transformer, so as to protect the power module of the bidirectional converter system. The short circuit detection method provided by the method also has the problems that only a near-end short circuit can be judged, and far-end short circuit protection cannot be detected, because the far-end short circuit is often triggered by direct current and cannot reach an overcurrent protection value.
In the above three direct-current side short-circuit protection schemes of the traction system, the following disadvantages exist at the same time: the far-end short circuit often causes that the direct current cannot trigger the overcurrent protection value, so that the far-end short circuit fault cannot be detected, and the reliable short circuit protection of the bidirectional converter cannot be realized.
Disclosure of Invention
1. The technical problem to be solved is as follows:
in order to solve the technical problems, the invention provides a bidirectional converter direct-current side short-circuit protection method based on rapid short-circuit current detection, when the direct-current side is short-circuited, a near-end short-circuit fault and a far-end short-circuit fault can be rapidly detected, a pulse signal of a power unit is immediately blocked, a bidirectional converter system stops running, and a thyristor loop is simultaneously opened, so that the power unit, a linked-tripping direct-current switch cabinet and an alternating-current switch cabinet of a bidirectional converter device are reliably protected, and the external direct-current short-circuit fault is reported.
2. The technical scheme is as follows:
a bidirectional converter direct current side short-circuit protection method based on rapid short-circuit current detection is applied to short-circuit protection of a subway traction power supply bidirectional converter; the method is characterized in that: the bidirectional converter comprises two groups of inversion modules; the direct current side and the alternating current side of each group of inversion modules are connected with a short-circuit protection device in parallel; each group of inversion modules comprises a plurality of inversion modules; a three-phase thyristor rectifier bridge circuit is arranged in the short-circuit protection device; the input end of the three-phase thyristor rectifier bridge circuit is connected to the direct current side of the bidirectional converter device, and the output end of the three-phase thyristor rectifier bridge circuit is connected to the output end of the inductor connected with the output end of the bidirectional converter device; the bottom controller of each inversion module is in communication connection with the main controller of the bidirectional converter device through optical fibers; the main control judges whether short circuit of the inversion module, namely near-end short circuit, and far-end short circuit which is not short circuit of the inversion module occurs according to the received voltage and current signals of the direct current side of the inversion module;
the short-circuit protection method comprises the steps that the main controller obtains direct current side voltages and direct current side currents of all inversion modules of the bidirectional converter device through a sampling circuit and judges whether short circuit occurs or not; if short circuit occurs, PWM pulse blocking signals are sent to the input end of each bottom layer controller corresponding to the inverter module with the short circuit immediately through the high-speed optical fiber, meanwhile, signals are output through a GPIO port of an FPGA processor of a main controller, driving signals are output to the gate level of the driving end of a three-phase thyristor rectifier bridge circuit through an optocoupler relay, short-circuit current immediately bypasses to the three-phase thyristor rectifier bridge, meanwhile, the main controller controls a breaker or/and an isolation knife of the inverter module to be disconnected, and therefore the inverter module is protected, and meanwhile, corresponding breakers in a gang-tripping AC-DC switch cabinet are connected.
Further, the step of judging whether the short circuit occurs by the dc side voltage and the dc side current of the bidirectional converter device obtained by the sampling circuit is as follows: the method comprises the following steps:
the method comprises the following steps: according to the rated capacity S of the transformer n Transforming and transformingRated voltage U of low-voltage side of device n Calculating the rated current I of the low-voltage side of the transformer of the bidirectional converter k (ii) a The following formula (1):
step two: according to short-circuit impedance U k Rated current I at low-voltage side of transformer k Calculating the maximum short-circuit current I of the low-voltage side of the near end n (ii) a The following formula (2):
step three: according to the direct current I of the three-phase rectification circuit d Corresponding relation to AC current I n Calculating the maximum DC current I during short circuit dmax The following formula (3):
step four: according to the bearable I of power device 2 t, calculating short-circuit protection time t by using the capacity, namely detecting the short-circuit fault in the time t;
step five: when short-circuit fault occurs, the pulse signal of the power unit is immediately blocked, the corresponding inversion module stops running, and the bypass short-circuit current of the thyristor loop is switched on at the same time, so that the power unit, the combined-trip direct-current switch cabinet and the alternating-current switch cabinet of the bidirectional converter device are protected, and the external direct-current short-circuit fault is reported.
Further, the third step specifically comprises the following steps:
and S31, detecting a near-end short-circuit fault: if the direct side current I d Greater than a preset direct current short-circuit protection threshold I thr Simultaneous direct voltage U d Less than a preset short-circuit protection threshold U of direct-current voltage thr Judging that a near-end short circuit fault occurs;
and S32, detecting a far-end short-circuit fault: detection ofThe current increment delta I of the direct current side and the corresponding time delta t are calculated, and the current change rate is calculated
Whether the current is larger than a preset direct current change rate protection threshold value delta I thr (ii) a If the current value is larger than the preset value, judging that a far-end short-circuit fault occurs; sending the information of the short-circuit fault at the far end to an upper computer, and sending an instruction to all bidirectional current transformation devices under the upper computer to check the short-circuit fault until finding an inversion module corresponding to the short-circuit fault;
and S33, if the short-circuit fault is judged, the main controller FPGA triggers a driving thyristor gate-level signal corresponding to the short-circuit through a hardware signal, and the short-circuit current immediately bypasses the three-phase thyristor rectifier bridge.
3. Has the advantages that:
(1) according to the invention, the three-phase thyristor rectifier bridge circuit is connected in parallel with the inverter module, and when the inverter module is short-circuited, the open thyristor loop is switched on, so that the power unit of the bidirectional converter device can be reliably protected.
(2) In the invention, in order to realize reliable protection of a power unit of the bidirectional converter, the short-circuit tolerance of an IGBT self anti-parallel diode which is an influencing factor is realized in a mode that short-circuit fault detection and protection are as fast as possible, and fault judgment is carried out by analyzing the ratio of current increment Delta I on a direct current side and time t.
Drawings
FIG. 1 is a flow chart of the present invention;
fig. 2 is a circuit diagram of a hardware detection circuit for detecting dc side current overflow in an embodiment.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
As shown in the attached figure 1, the bidirectional converter direct current side short-circuit protection method based on rapid short-circuit current detection is applied to short-circuit protection of a subway traction power supply bidirectional converter; the method is characterized in that: the bidirectional converter comprises two groups of inversion modules; the direct current side and the alternating current side of each group of inversion modules are connected with a short-circuit protection device in parallel; each group of inversion modules comprises a plurality of inversion modules; a three-phase thyristor rectifier bridge circuit is arranged in the short-circuit protection device; the input end of the three-phase thyristor rectifier bridge circuit is connected to the direct current side of the bidirectional converter device, and the output end of the three-phase thyristor rectifier bridge circuit is connected to the output end of the inductor connected with the output end of the bidirectional converter device; the bottom controller of each inversion module is in communication connection with the main controller of the bidirectional converter device through optical fibers; and the main control judges whether short circuit of the inversion module, namely near-end short circuit, and far-end short circuit which is not short circuit of the inversion module occurs according to the received voltage and current signals of the direct current side of the inversion module.
The short-circuit protection method comprises the steps that the main controller obtains direct current side voltages and direct current side currents of all inversion modules of the bidirectional converter device through a sampling circuit and judges whether short circuit occurs or not; if the short circuit occurs, PWM pulse blocking signals are sent to the input end of each bottom layer controller corresponding to the short-circuit inversion module immediately through the high-speed optical fibers, meanwhile, signals are output through a GPIO port of an FPGA processor of a main controller, and then the signals are output to the gate level of the circuit driving end of a three-phase thyristor rectifier bridge through an optocoupler relay, short-circuit current immediately bypasses to the three-phase thyristor rectifier bridge, meanwhile, the main controller controls the breaker or/and the isolating knife of the inversion module to be disconnected, so that the inversion module is protected, and meanwhile, corresponding breakers in a jump AC/DC switch cabinet are connected.
Further, the step of judging whether the short circuit occurs by the dc side voltage and the dc side current of the bidirectional converter device obtained by the sampling circuit is as follows: the method comprises the following steps:
the method comprises the following steps: according to the rated capacity S of the transformer n Rated voltage U of low-voltage side of transformer n Calculating the rated current I of the low-voltage side of the transformer of the bidirectional converter k (ii) a The following formula (1):
step two: according to short-circuit impedance U k Rated current I at low-voltage side of transformer k Calculating the proximal end low voltage side maximumLarge short-circuit current I n (ii) a The following formula (2):
step three: according to the direct current I of the three-phase rectification circuit d Corresponding relation to AC current I n Calculating the maximum DC current I during short circuit dmax The following formula (3):
step four: according to the bearable I of power device 2 And (5) calculating short-circuit protection time t by the t capacity, namely detecting the short-circuit fault in the t time.
Step five: when short-circuit fault occurs, the pulse signal of the power unit is immediately blocked, the corresponding inversion module stops running, and the bypass short-circuit current of the thyristor loop is switched on at the same time, so that the power unit, the combined-trip direct-current switch cabinet and the alternating-current switch cabinet of the bidirectional converter device are protected, and the external direct-current short-circuit fault is reported.
Further, the third step specifically comprises the following steps:
and S31, detecting a near-end short-circuit fault: if the direct side current I d Greater than a preset direct current short-circuit protection threshold I thr Simultaneous direct current voltage U d Less than a preset short-circuit protection threshold U of direct-current voltage thr Judging that a near-end short circuit fault occurs;
and S32, detecting a far-end short-circuit fault: detecting the current increment delta I and the corresponding time delta t on the direct current side, and calculating the current change rate
Whether the current is larger than a preset direct current change rate protection threshold value delta I thr (ii) a If the current value is larger than the preset value, judging that a far-end short-circuit fault occurs; and sending the information of the short-circuit fault at the far end to an upper computer, and sending an instruction to all bidirectional current transformers controlled by the upper computer to carry out the short-circuit faultChecking until finding the inversion module corresponding to the short-circuit fault;
and S33, if the short-circuit fault is judged, the main controller FPGA triggers a driving thyristor gate-level signal corresponding to the short-circuit through a hardware signal, and the short-circuit current immediately bypasses the three-phase thyristor rectifier bridge.
The specific embodiment is as follows:
in the embodiment, the rated capacity is 2200kVA, the voltage is 35kV, and the short-circuit resistance is 6.7% (full ride-through resistance); the rated line voltage 950V of the two windings on the secondary side is taken as an example, the maximum short-circuit current of the primary side is 541.8A, and the short-circuit current converted to the secondary side is 20 kA. According to the corresponding relation between the direct current and the alternating current of the three-phase uncontrolled rectifying circuit, the coefficient is 0.816, and the direct-current side current Id is 24.5 kA.
In order to reliably protect the power unit of the bidirectional converter device, the influence factor is the short circuit tolerance (I) of the IGBT self anti-parallel diode 2 t), so that the short-circuit fault detection and protection are as fast as possible, a direct-side short-circuit current I d Greater than a preset direct current short-circuit protection threshold I thr Simultaneous direct current voltage U d Less than a preset short-circuit protection threshold U of direct-current voltage thr I.e. a near end short circuit fault occurs, and additionally a far end short circuit fault needs to be detected.
Detecting a far-end short-circuit fault: detecting the current increment and time of the DC side, and calculating the current change rate
Greater than a predetermined DC current change rate protection threshold value Delta I thr Namely, the occurrence of the far-end short-circuit fault is judged.
When short-circuit fault occurs, the pulse signal of the power unit is immediately blocked, the bidirectional converter system stops running, and the bypass short-circuit current of the thyristor loop is switched on, so that the power unit, the combined-trip direct-current switch cabinet and the alternating-current switch cabinet of the bidirectional converter device are reliably protected, and the external direct-current short-circuit fault is reported.
On a hardware circuit, as shown in fig. 2, a direct current side current overcurrent hardware detection circuit is designed, wherein OC _ dc-is direct current side current, Idc _ OC is a hardware overcurrent detection signal, and the signal is directly input into a GPIO port of an FPGA, so that the short-circuit current detection circuit basically has no time delay.
In the design of the control system, the controller adopts an FPGA chip. When the FPGA detects a short-circuit fault, the IGBT pulse is immediately blocked, the thyristor loop is simultaneously switched on, and the direct-current switch cabinet and the alternating-current switch cabinet are simultaneously linked and tripped, and the external direct-current short-circuit fault is reported.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (3)
1. A bidirectional converter direct current side short-circuit protection method based on rapid short-circuit current detection is applied to short-circuit protection of a subway traction power supply bidirectional converter; the method is characterized in that: the bidirectional converter comprises two groups of inversion modules; the direct current side and the alternating current side of each group of inversion modules are connected with a short-circuit protection device in parallel; each group of inversion modules comprises a plurality of inversion modules; a three-phase thyristor rectifier bridge circuit is arranged in the short-circuit protection device; the input end of the three-phase thyristor rectifier bridge circuit is connected to the direct current side of the bidirectional converter device, and the output end of the three-phase thyristor rectifier bridge circuit is connected to the output end of the inductor connected with the output end of the bidirectional converter device; the bottom controller of each inversion module is in communication connection with the main controller of the bidirectional converter device through optical fibers; the main control judges whether short circuit of the inversion module, namely near-end short circuit, and far-end short circuit which is not short circuit of the inversion module occurs according to the received voltage and current signals of the direct current side of the inversion module;
the short-circuit protection method comprises the steps that the main controller obtains direct current side voltages and direct current side currents of all inversion modules of the bidirectional converter device through a sampling circuit and judges whether short circuit occurs or not; if the short circuit occurs, PWM pulse blocking signals are sent to the input end of each bottom layer controller corresponding to the short-circuit inversion module immediately through the high-speed optical fibers, meanwhile, signals are output through a GPIO port of an FPGA processor of a main controller, and then the signals are output to the gate level of the circuit driving end of a three-phase thyristor rectifier bridge through an optocoupler relay, short-circuit current immediately bypasses to the three-phase thyristor rectifier bridge, meanwhile, the main controller controls the breaker or/and the isolating knife of the inversion module to be disconnected, so that the inversion module is protected, and meanwhile, corresponding breakers in a jump AC/DC switch cabinet are connected.
2. The fast short-circuit current detection-based bidirectional converter direct current side short-circuit protection method according to claim 1, characterized in that: the judgment of whether the short circuit occurs through the direct current side voltage and the direct current side current of the bidirectional converter device obtained by the sampling circuit is as follows: the method comprises the following steps:
the method comprises the following steps: according to the rated capacity S of the transformer n Rated voltage U of low-voltage side of transformer n Calculating the rated current I of the low-voltage side of the transformer of the bidirectional converter k (ii) a The following formula (1):
step two: according to short-circuit impedance U k Rated current I at low-voltage side of transformer k Calculating the maximum short-circuit current I of the low-voltage side of the near end n (ii) a The following formula (2):
step three: according to the direct current I of the three-phase rectification circuit d Corresponding relation to AC current I n Calculating the maximum DC current I at short circuit dmax The following formula (3):
step four: according to the bearable I of power device 2 t, calculating short-circuit protection time t by using the capacity, namely detecting the short-circuit fault in the time t;
step five: when short-circuit fault occurs, the pulse signal of the power unit is immediately blocked, the corresponding inversion module stops running, and the bypass short-circuit current of the thyristor loop is switched on at the same time, so that the power unit, the combined-trip direct-current switch cabinet and the alternating-current switch cabinet of the bidirectional converter device are protected, and the external direct-current short-circuit fault is reported.
3. The fast short-circuit current detection-based bidirectional converter direct current side short-circuit protection method according to claim 2, characterized in that: the third step specifically comprises the following steps:
and S31, detecting a near-end short-circuit fault: if the direct side current I d Greater than a preset direct current short-circuit protection threshold I thr Simultaneous direct current voltage U d Less than a preset short-circuit protection threshold U of direct-current voltage thr Judging that a near-end short circuit fault occurs;
and S32, detecting a far-end short-circuit fault: detecting the current increment delta I and the corresponding time delta t on the direct current side, and calculating the current change rate
Whether the current is larger than a preset direct current change rate protection threshold value delta I thr (ii) a If the current value is larger than the preset value, judging that a far-end short-circuit fault occurs; sending the information of the short-circuit fault at the far end to an upper computer, and sending an instruction to all bidirectional current transformation devices under the upper computer to check the short-circuit fault until finding an inversion module corresponding to the short-circuit fault;
and S33, if the short-circuit fault is judged, the main controller FPGA triggers a driving thyristor gate-level signal corresponding to the short-circuit through a hardware signal, and the short-circuit current immediately bypasses the three-phase thyristor rectifier bridge.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117559661A (en) * | 2024-01-10 | 2024-02-13 | 共鸿电器有限公司 | Method, equipment and medium for fault breaking control of draw-out type switch cabinet |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117559661A (en) * | 2024-01-10 | 2024-02-13 | 共鸿电器有限公司 | Method, equipment and medium for fault breaking control of draw-out type switch cabinet |
| CN117559661B (en) * | 2024-01-10 | 2024-03-29 | 共鸿电器有限公司 | Method, equipment and medium for fault breaking control of draw-out type switch cabinet |
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