CN117458412A - Electric power system and control method thereof - Google Patents
Electric power system and control method thereof Download PDFInfo
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- CN117458412A CN117458412A CN202311429085.0A CN202311429085A CN117458412A CN 117458412 A CN117458412 A CN 117458412A CN 202311429085 A CN202311429085 A CN 202311429085A CN 117458412 A CN117458412 A CN 117458412A
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- 238000001514 detection method Methods 0.000 claims abstract description 96
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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
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/28—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for meshed systems
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Abstract
The embodiment of the invention discloses a power system and a control method thereof, wherein a control module is configured in the whole power system and is connected with current detection modules at all circuit breakers in a power grid, namely all the circuit breakers in the power grid correspond to the same relay protection device, fault points are determined according to currents detected by all the current detection modules through the control module, and a switch module in a power grid with the fault points is controlled to be disconnected. According to the technical scheme, no matter the fault point is in the higher-level power grid or the lower-level power grid, the time from determining the fault point to controlling the switch module to be disconnected in the power grid of the level where the fault point is located is smaller than the preset time, so that the time from determining the fault point to controlling the switch module to be disconnected in the power grid of the level where the fault point is located is very short, the fault point can be rapidly cut off when the fault point is in any level of power grid, and the influence of the power grid fault on the power grid is reduced.
Description
Technical Field
The embodiment of the invention relates to the technical field of relay protection of power systems, in particular to a power system and a control method thereof.
Background
In order to ensure the safety of the power system, the relay protection device of the power system is widely applied.
In the prior art, the existing power system relay protection devices are all independent, so that a single power supply line protection function is realized, and because of the existence of a power supply level of the power system, a certain time delay exists in upper-level protection fixed value setting on the protection function cooperation of upper and lower-level power grids so as to meet the correctness and selectivity of the relay protection function. Therefore, when the upper power grid line fails, the relay protection device cuts off the time of the short-circuit fault point, and the short-circuit fault point seriously affects the power supply reliability and the power supply safety of the power supply system.
Disclosure of Invention
The invention provides a power system and a control method thereof, which are used for rapidly cutting off fault points, reducing the influence of short-circuit faults on a power grid, improving the power supply reliability and ensuring the power supply safety.
In a first aspect, an embodiment of the present invention provides an electric power system, including: at least two stages of power grids and control modules;
each stage of power grid comprises a switch module, a current detection module is arranged at the position of the switch module, a control module is electrically connected with the current detection module, and the control module is also electrically connected with the switch module;
the control module is used for determining a fault point according to the current detected by the current detection module and controlling the switch module to be disconnected in the power grid of the stage where the fault point is located;
and the time from determining the fault point to controlling the switch module to be disconnected in the power grid of the stage where the fault point is located is smaller than the preset time.
Optionally, the at least two-stage power grid comprises a first-stage power grid and a second-stage power grid, and the second-stage power grid is a lower-stage power grid of the first-stage power grid;
the control module is used for controlling the switch module in the first-stage power grid to be disconnected when the fault point is determined to be in the first-stage power grid;
the control module is also used for controlling the switch module of the second-stage power grid to be disconnected when the fault point is determined to be in the second-stage power grid;
the first time from the determination of the fault point in the first-stage power grid to the control of the switching module in the first-stage power grid to be disconnected is equal to the second time corresponding to the determination of the fault point in the second-stage power grid to the control of the switching module in the second-stage power grid to be disconnected.
Optionally, each stage of power grid further comprises a voltage detection module, wherein the voltage detection module is electrically connected with the control module and is used for detecting the bus voltage of the power grid at the stage;
the control module is used for determining that the fault point is in the first-stage power grid when the current detected by the current detection module in the first-stage power grid is greater than a preset current threshold value and the bus voltage of the second-stage power grid is 0 and the bus voltage of the first-stage power grid is reduced and greater than 0;
the control module is further used for determining that the fault point is in the second-stage power grid when the current detected by the current detection module in the second-stage power grid is larger than a preset current threshold value, the bus voltage of the second-stage power grid is reduced and larger than 0, and the reduction degree of the bus voltage of the first-stage power grid is smaller than that of the second-stage power grid.
Optionally, the control module comprises an input unit, a control unit and an output unit, wherein the input unit is electrically connected with the current detection module and is used for collecting the current detected by the current detection module; the control unit is respectively and electrically connected with the input unit and the output unit, and is used for determining a fault point according to the current and outputting a control signal to a switch module of a power grid of a stage where the fault point is located through the output unit so as to control the switch module to be disconnected.
Optionally, the current detection module comprises a current transformer, and the switch module comprises a circuit breaker; the fault points include short circuit fault points.
In a second aspect, an embodiment of the present invention further provides a control method of an electric power system, including:
determining a fault point according to the current detected by the current detection module, and controlling a switch module in a power grid of a stage where the fault point is located to be disconnected;
and the time from determining the fault point to controlling the switch module to be disconnected in the power grid of the stage where the fault point is located is smaller than the preset time.
Optionally, the at least two-stage power grid comprises a first-stage power grid and a second-stage power grid, and the second-stage power grid is a lower-stage power grid of the first-stage power grid;
determining a fault point according to the current detected by the current detection module, and controlling the switch module to be disconnected in the power grid of the stage where the fault point is located, wherein the method comprises the following steps:
when the fault point is determined to be in the first-stage power grid, a switch module in the first-stage power grid is controlled to be disconnected; when the fault point is determined to be in the second-stage power grid, the switch module of the second-stage power grid is controlled to be disconnected;
the first time from the determination of the fault point in the first-stage power grid to the control of the switching module in the first-stage power grid to be disconnected is equal to the second time corresponding to the determination of the fault point in the second-stage power grid to the control of the switching module in the second-stage power grid to be disconnected.
Optionally, the control module determines a fault point according to the current detected by the current detection module, and controls the switch module to be turned off in the power grid of the stage where the fault point is located, including:
at least when the current detected by the current detection module in the first-stage power grid is larger than a preset current threshold value, determining that a fault point is in the first-stage power grid, and controlling a switch module in the first-stage power grid to be disconnected;
and determining that the fault point is in the second-stage power grid at least when the current detected by the current detection module in the second-stage power grid is larger than a preset current threshold value, and controlling the switch module in the second-stage power grid to be disconnected.
Optionally, at least when the current detected by the current detection module in the second-stage power grid is greater than a preset current threshold, determining that the fault point is in the second-stage power grid, and controlling the switch module in the second-stage power grid to be turned off, including:
when the current detected by the current detection module in the first-stage power grid and the current detected by the current detection module in the second-stage power grid are both greater than a preset current threshold, determining that a fault point is in the second-stage power grid, and controlling a switch module in the second-stage power grid to be disconnected;
after the switching module in the second-stage power grid is disconnected, the current detected by the current detection module in the first-stage power grid is kept larger than a preset current threshold value, the fault point is determined to be still in the first-stage power grid, and the switching module in the first-stage power grid is controlled to be disconnected.
Optionally, each stage of power grid further comprises a voltage detection module; determining a fault point according to the current detected by the current detection module, and controlling the switch module to be disconnected in the power grid of the stage where the fault point is located, wherein the method comprises the following steps:
when the current detected by the current detection module in the first-stage power grid is greater than a preset current threshold value and the bus voltage of the second-stage power grid is 0, determining that a fault point is in the first-stage power grid and controlling the switching module in the first-stage power grid to be disconnected when the bus voltage of the first-stage power grid is reduced and is greater than 0;
when the current detected by the current detection module in the second-stage power grid is larger than a preset current threshold value, the bus voltage of the second-stage power grid is reduced and larger than 0, and the reduction degree of the bus voltage of the first-stage power grid is smaller than that of the second-stage power grid, determining that a fault point is in the second-stage power grid, and controlling the switching module in the first-stage power grid to be disconnected.
According to the power system and the control method thereof, the control module is configured in the whole power system and is connected with the current detection modules at all the circuit breakers in the power grid, namely, all the circuit breakers in the power grid correspond to the same relay protection device, the control module determines the fault point according to the current detected by each current detection module, and the switch module in the power grid with the fault point is controlled to be disconnected. According to the technical scheme, no matter the fault point is in the higher-level power grid or the lower-level power grid, the time from determining the fault point to controlling the switch module to be disconnected in the power grid of the level where the fault point is located is smaller than the preset time, and the time from determining the fault point to controlling the switch module to be disconnected in the power grid of the level where the fault point is located is very short, so that the fault point can be rapidly removed when the fault point is in any level of power grid, the influence of the power grid fault on the power grid is reduced, the power supply reliability is improved, and the power supply safety is ensured.
Drawings
FIG. 1 is a schematic diagram of a related art power system;
fig. 2 is a schematic structural diagram of an electric power system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of another power system according to an embodiment of the present invention;
fig. 4 is a flowchart of a control method of an electric power system according to an embodiment of the present invention;
FIG. 5 is a flowchart of another control method of an electric power system according to an embodiment of the present invention;
fig. 6 is a flowchart of another control method of an electric power system according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Fig. 1 is a schematic diagram of a power system in the related art, and referring to fig. 1, the power system includes a multi-stage power grid, and fig. 1 illustrates a case where the power system includes a two-stage power grid. Referring to fig. 1, each stage of power grid comprises circuit breakers, each circuit breaker is provided with a relay protection device 3, and the relay protection device 3 is connected with voltage and current signals at the corresponding circuit breaker. In the scheme, the relay protection devices 3 of each circuit breaker independently operate, and the protection constant values of the upper and lower relay protection devices 3 are mutually related to ensure the selectivity and the correctness of relay protection actions. When a short-circuit fault occurs at the short-circuit point 9 in fig. 1, short-circuit currents exist at the upper circuit breaker 4 of the upper power grid 1 and the lower circuit breaker 5 of the lower power grid 2, and at this time, the lower circuit breaker 5 should trip, and the upper circuit breaker 4 does not trip (the power failure range will be enlarged after tripping).
Taking quick break protection as an example: to ensure the correctness of the protection operation, it is assumed that the time limit t1=0s of the quick-break protection operation of the lower circuit breaker 5, and the time limit t2 of the quick-break protection operation of the upper circuit breaker 4 should be set to be one time limit step larger, and set to t2=0s+Δts (generally take 0.5-0.7 s). Thereby causing the following to occur: when a short circuit fault occurs at the short circuit point 8 in fig. 1, the circuit breaker 4 will delay the tripping of deltats to cut off the fault point, and the voltage of the upper power grid 1 will drop greatly, which seriously affects the safety and stability of the power supply of the upper power grid 1.
For the foregoing reasons, an embodiment of the present invention provides an electric power system, and fig. 2 is a schematic structural diagram of the electric power system according to the embodiment of the present invention, and referring to fig. 2, the electric power system includes: at least two stages of power grids 10 and control modules 20; each stage of power grid 10 comprises a switch module 101, a current detection module 102 is arranged at the position of the switch module 101, a control module 20 is electrically connected with the current detection module 102, and the control module 20 is also electrically connected with the switch module 101; the control module 20 is used for determining a fault point according to the current detected by the current detection module 102 and controlling the switch module 101 to be disconnected in the power grid 10 of the stage where the fault point is located; wherein, from determining the fault point, the time from the fault point to the switch module 101 opening in the power grid 10 controlling the stage where the fault point is located is less than the preset time.
Referring to fig. 2, a case in which the power system includes two-stage power grids 10 is exemplarily shown in fig. 2, and at least two-stage power grids 10 include a first-stage power grid 11 and a second-stage power grid 12, where the second-stage power grid 12 is a lower-stage power grid 10 of the first-stage power grid 11. Each stage of the power grid 10 comprises a switching module 101, wherein the switching modules 101 may comprise circuit breakers. Wherein the switch module 101 is further provided with a current detection module 102, the current detection module 102 may comprise a current transformer, and the current detection module 102 may detect the current at the switch module 101.
In this embodiment, the power system further includes a control module 20, where the control module 20 is electrically connected to the current detection modules 102 in the power grids 10 at all levels, so that the current in the power grids 10 at all levels can be obtained from the current detection modules 102. In this embodiment, a control module 20 is provided for the whole power system, and the control module 20 is connected to current detection modules 102 at all the circuit breakers in the power grid 10, that is, all the circuit breakers in the power grid 10 correspond to the same relay protection device (that is, the control module 20 in this embodiment), and the control module 20 determines a fault point according to the current detected by each current detection module 102, and controls the switch module 101 in the power grid 10 where the fault point is located to be disconnected. Wherein the fault point may comprise a short circuit fault point. The control module 20 may be a programmable microcomputer relay protection device, and the control module 20 may be programmed with a program for determining a fault point, where the program for determining a fault point may include program logic for determining a fault point according to the current detected by the current detection module 102 at each switch module 101.
Illustratively, when the control module 20 determines that the point of failure is in the first-stage power grid 11, the switch module 101 in the first-stage power grid 11 is controlled to open; the control module 20 controls the switching module 101 of the second-stage power grid 12 to be turned off when it is determined that the fault point is in the second-stage power grid 12. In addition, in this embodiment, no matter the fault point is in the higher-level power grid 10 or the lower-level power grid 10, the time from determining the fault point to controlling the switch module 101 to be turned off in the power grid 10 of the level where the fault point is located is less than the preset time, and in some alternative embodiments of the present invention, the preset time may be the longest time required for the control module 20 to turn off from determining the fault point to controlling the switch module 101 in the power grid 10 of the level where the fault point is located; in other alternative embodiments of the present invention, the preset time may be less than the delay time set in the prior art (i.e., 0.5 to 0.7s as mentioned in the above embodiments). In other words, in the present embodiment, for the occurrence of the fault point in the upper-level power grid 10, the time for controlling the switching module 101 to be turned off in the upper-level power grid 10 is not delayed with respect to the time for the occurrence of the fault point in the lower-level power grid 10, and the time for controlling the switching module 101 to be turned off in the lower-level power grid 10. By the arrangement, the time from determining the fault point to controlling the switch module 101 to be disconnected in the level power grid 10 where the fault point is located is short, so that the fault point can be rapidly removed when the fault point is in any level power grid 10, and the influence of the power grid 10 fault on the power grid 10 is reduced.
In the power system of this embodiment, a control module is configured in the whole power system, and the control module is connected with current detection modules at all circuit breakers in the power grid, that is, all circuit breakers in the power grid correspond to the same relay protection device, and determines a fault point according to the current detected by each current detection module through the control module, and controls a switch module in the power grid where the fault point is located to be disconnected. In this embodiment, no matter the fault point is in the higher level power grid or the lower level power grid, from determining the fault point, the time from controlling the disconnection of the switch module in the power grid of the level where the fault point is located is less than the preset time, so the time from determining the fault point to controlling the disconnection of the switch module in the power grid of the level where the fault point is located is very short, the fault point can be rapidly cut off when the fault point is in any level of power grid, the influence of the power grid fault on the power grid is reduced, the power supply reliability is ensured, and the power supply safety is ensured.
With continued reference to fig. 2, as described above, at least two levels of power grid 10 include a first level of power grid 11 and a second level of power grid 12, the second level of power grid 12 being a lower level of the first level of power grid 11; the control module 20 is configured to control the switch module 101 in the first-stage power grid 11 to be turned off when the fault point is determined to be in the first-stage power grid 11; the control module 20 is further configured to control the switching module 101 of the second-stage power grid 12 to be turned off when the fault point is determined to be in the second-stage power grid 12.
Wherein, from determining that the fault point is in the first-stage power grid 11 to controlling the switching module 101 in the first-stage power grid 11 to be turned off is equal to a second time corresponding to determining that the fault point is in the second-stage power grid 12 to controlling the switching module 101 in the second-stage power grid 12 to be turned off when the fault point is in the second-stage power grid 12 (i.e., the fault point is the second fault point 90), for example, determining that the fault point is in the second-stage power grid 12 to the first time for controlling the switching module 101 in the second-stage power grid 12 to be turned off is t3, determining that the fault point is in the first-stage power grid 11 (i.e., the fault point is the first fault point 80), and also determining that the first time for controlling the switching module 101 in the first-stage power grid 11 to be turned off is t3. That is, for the fault point appearing in the upper power grid, the time of switching off the switch module 101 in the upper power grid is controlled to appear in the lower power grid relative to the fault point, and the time of switching off the switch module 101 in the lower power grid is controlled to have no delay, so that the relay protection of the power system is realized without setting a tripping delay function, the fault point is rapidly removed, the fault point is ensured to be rapidly removed when the fault point appears in the upper power grid, and the influence of the power grid 10 fault on the power grid 10 is reduced.
With continued reference to fig. 2, on the basis of the above technical solution, optionally, each stage of power grid 10 further includes a voltage detection module 103, where the voltage detection module 103 is electrically connected to the control module 20, and the voltage detection module 103 is configured to detect a bus voltage of the stage of power grid 10; the control module 20 is configured to determine that the fault point is in the first-stage power grid 11 when the current detected by the current detection module 102 in the first-stage power grid 11 is greater than a preset current threshold, and the bus voltage of the second-stage power grid 12 is 0, and the bus voltage of the first-stage power grid 11 drops and is greater than 0; the control module 20 is further configured to determine that the fault point is in the second-stage power grid 12 when the current detected by the current detection module 102 in the second-stage power grid 12 is greater than the preset current threshold, the bus voltage of the second-stage power grid 12 decreases and is greater than 0, and the degree of decrease of the bus voltage of the first-stage power grid 11 is less than the degree of decrease of the bus voltage of the second-stage power grid 12.
The voltage detection module 103 may include a voltage transformer, among others.
Specifically, when the first-stage power grid 11 has a short-circuit fault, the current of the first-stage power grid 11 is a short-circuit current with a large current value, so the current value detected by the current detection module 102 in the first-stage power grid 11 may preset a current threshold. When the first-stage power grid 11 has a short-circuit fault, the second-stage power grid 12 has no bus voltage, that is, the bus voltage of the second-stage power grid 12 is 0, the bus voltage of the first-stage power grid 11 also decreases, but the bus voltage of the first-stage power grid 11 is still greater than 0. In the event of a short-circuit fault in the power network 10 of the second-stage power network 12, the bus voltage of the second-stage power network 12 will drop rapidly, and the bus voltage of the first-stage power network 11 will drop, but the degree of drop of the bus voltage of the first-stage power network 11 will be smaller than the degree of drop of the bus voltage of the second-stage power network 12, wherein the degree of drop of the bus voltage can be characterized by the ratio of the difference between the bus voltage before drop and the bus voltage after drop to the bus voltage before drop.
Therefore, in this embodiment, by setting that each stage of power grid 10 further includes a voltage detection module 103, detecting the bus voltage of the power grid 10 at the stage of power grid 10 by the voltage detection module 103, the control module 20 accurately determines the location of the fault point in the power system by using the current in the current detection module 102 of each stage of power grid 10 as the main criterion for determining the fault point, and using the voltage detected by the voltage detection module 103 of each stage of power grid 10 as the auxiliary criterion for determining the fault point.
Fig. 3 is a schematic structural diagram of another power system according to an embodiment of the present invention, referring to fig. 3, optionally, the control module 20 includes an input unit 201, a control unit 202, and an output unit 203, where the input unit 201 is electrically connected to the current detection module 102, and is configured to collect a current detected by the current detection module 102; the control unit 202 is electrically connected to the input unit 201 and the output unit 203, and the control unit 202 is configured to determine a fault point according to the current, and output a control signal to the switch module 101 of the power grid 10 at the stage where the fault point is located through the output unit 203, so as to control the switch module 101 to be turned off.
The input unit 201 may collect the current collected by the current detection module 102 and convert the collected current into a signal that can be identified by the control unit 202, where the control unit 202 may include a central processing unit, a single-chip microcomputer, or a PLC, and a program for identifying a fault point may be loaded in the control unit 202, so that the control unit 202 may determine the fault point. The output unit 203 may convert the signal output by the control unit 202 into a signal that can be recognized by the switch module 101, and output the signal to the switch module 101.
The embodiment of the invention also provides a control method of the power system, which can be applied to the power system of any embodiment of the invention, and comprises the following steps: determining a fault point according to the current detected by the current detection module, and controlling a switch module in a power grid of a stage where the fault point is located to be disconnected; and the time from determining the fault point to controlling the switch module to be disconnected in the power grid of the stage where the fault point is located is smaller than the preset time.
The control method of the power system according to the embodiment is applied to the power system according to any of the embodiments of the present invention, and has the advantages of the power system according to any of the embodiments of the present invention.
On the basis of the technical scheme, optionally, at least two stages of power grids comprise a first stage power grid and a first stage power grid, and the first stage power grid is a lower stage power grid of the first stage power grid.
Fig. 4 is a flowchart of a control method of an electric power system according to an embodiment of the present invention, and referring to fig. 4, optionally, the control method of the electric power system includes:
and 210, when the fault point is determined to be in the first-stage power grid, controlling a switch module in the first-stage power grid to be disconnected.
And 220, when the fault point is determined to be in the second-stage power grid, controlling a switch module of the first-stage power grid to be disconnected. The first time from the determination of the fault point in the first-stage power grid to the control of the switching module in the first-stage power grid to be disconnected is equal to the second time corresponding to the determination of the fault point in the second-stage power grid to the control of the switching module in the second-stage power grid to be disconnected.
The fault point is in the first-stage power grid, namely, the fault point exists only in the first-stage power grid, and the fault points do not exist in other stages of power grids. The fault point is in the second-stage power grid, namely, only the fault point exists in the second-stage power grid, and no fault point exists in other stages of power grids.
Fig. 5 is a flowchart of another control method of an electric power system according to an embodiment of the present invention, and referring to fig. 5, optionally, the control method of the electric power system includes:
and 310, determining that the fault point is in the first-stage power grid at least when the current detected by the current detection module in the first-stage power grid is greater than a preset current threshold value, and controlling the switch module in the first-stage power grid to be disconnected.
Specifically, when a short-circuit fault point occurs in the first-stage power grid, the current in the first-stage power grid must rise to a very large short-circuit current, in this embodiment, when the current detected by the current detection module in the first-stage power grid is at least greater than a preset current threshold, the fault point is determined in the first-stage power grid, and the switch module in the first-stage power grid is controlled to be disconnected, so that when the fault point exists in the first-stage power grid, the fault point can be timely removed, and the influence of the power grid fault on the power grid is reduced.
Optionally, the step 310 includes determining that the fault point is in the first-stage power grid when the current detected by the current detection module in the first-stage power grid is greater than a preset current threshold, the bus voltage of the first-stage power grid is 0, and the bus voltage of the first-stage power grid drops and is greater than 0, and controlling the switch module in the first-stage power grid to be turned off.
And 320, at least when the current detected by the current detection module in the second-stage power grid is greater than a preset current threshold value, determining that the fault point is in the second-stage power grid, and controlling the switch module in the second-stage power grid to be disconnected.
Specifically, when a short-circuit fault point occurs in the second-stage power grid, the current in the second-stage power grid must rise to a very large short-circuit current, in this embodiment, when the current detected by the current detection module in the second-stage power grid is at least greater than a preset current threshold, the fault point is determined in the second-stage power grid, and the switch module in the second-stage power grid is controlled to be disconnected, so that when the fault point exists in the second-stage power grid, the fault point can be timely cut off, and the influence of the power grid fault on the power grid is reduced.
Optionally, the step 320 includes determining that the fault point is in the second-stage power grid when the current detected by the current detection module in the second-stage power grid is greater than the preset current threshold, the bus voltage of the second-stage power grid is reduced and greater than 0, and the degree of reduction of the bus voltage of the second-stage power grid is smaller than the degree of reduction of the bus voltage of the second-stage power grid, and controlling the switch module in the second-stage power grid to be turned off.
Fig. 6 is a flowchart of another control method of an electric power system according to an embodiment of the present invention, and referring to fig. 6, optionally, the control method of the electric power system includes:
and step 410, determining that the fault point is in the first-stage power grid at least when the current detected by the current detection module in the first-stage power grid is greater than a preset current threshold value, and controlling the switch module in the first-stage power grid to be disconnected.
And step 420, determining that the fault point is in the second-stage power grid when the current detected by the current detection module in the first-stage power grid and the current detected by the current detection module in the second-stage power grid are both greater than a preset current threshold value, and controlling the switch module in the second-stage power grid to be turned off.
Specifically, when the current detected by the current detection module in the first-stage power grid and the current detected by the current detection module in the second-stage power grid are both greater than a preset current threshold, the fault occurring in the power system may include two situations, where one situation is that only the second-stage power grid fails, and the other situation is that both the first-stage power grid and the second-stage power grid fail. In the step, when the current detected by the current detection module in the first-stage power grid and the current detected by the current detection module in the second-stage power grid are both larger than a preset current threshold, determining that a fault point is in the second-stage power grid, and controlling a switch module in the second-stage power grid to be disconnected, so that the fault point is timely cut off when the fault occurs in the second-stage power grid; when the first-stage power grid and the second-stage power grid both comprise fault points, the switch module in the second-stage power grid is disconnected firstly, and whether the fault points occur in the first-stage power grid can be conveniently and subsequently judged.
And 430, after the switch module in the second-stage power grid is disconnected, the current detected by the current detection module in the first-stage power grid is kept larger than a preset current threshold value, the fault point is determined to be still in the first-stage power grid, and the switch module in the first-stage power grid is controlled to be disconnected.
Specifically, after the switch module in the second-stage power grid is disconnected, the current detected by the current detection module in the first-stage power grid is kept larger than a preset current threshold value, so that a fault point exists in the first-stage power grid, the switch module in the first-stage power grid is further controlled to be disconnected in time, and the influence of power grid faults on the power grid is reduced. If the current detected by the current detection module in the first-stage power grid is smaller than or equal to a preset current threshold after the switch module in the second-stage power grid is disconnected, and the fact that a fault point does not exist in the first-stage power grid is indicated, the switch module in the first-stage power grid is controlled to be conducted.
In this embodiment, although the switch module in the first-stage power grid is also turned off after the switch module in the second-stage power grid when both the first-stage power grid and the second-stage power grid have fault points, in this embodiment, after the switch module in the second-stage power grid, the control module only needs to determine whether the current detected by the current detection module in the first-stage power grid is greater than the determination time of the preset current threshold value, and the time is equivalent to the delay time of the circuit breaker in the upper-stage power grid being turned off relative to the circuit breaker in the lower-stage power grid in the prior art, so that the fault points can still be ensured to be rapidly cut off.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (10)
1. An electrical power system, comprising: at least two stages of power grids and control modules;
each stage of the power grid comprises a switch module, a current detection module is arranged at the position of the switch module, the control module is electrically connected with the current detection module, and the control module is also electrically connected with the switch module;
the control module is used for determining a fault point according to the current detected by the current detection module and controlling the switch module to be disconnected in the power grid of the stage where the fault point is located;
and from determining the fault point to controlling the switching module to be disconnected in the power grid of the stage where the fault point is located, the time is less than the preset time.
2. The power system of claim 1, wherein at least two of the power grids include a first-stage power grid and a second-stage power grid, the second-stage power grid being a lower-stage power grid of the first-stage power grid;
the control module is used for controlling the switch module in the first-stage power grid to be disconnected when the fault point is determined to be in the first-stage power grid;
the control module is further used for controlling the switch module of the second-stage power grid to be disconnected when the fault point is determined to be in the second-stage power grid;
wherein a first time from determining that the fault point is in the first-stage power grid to controlling the switching module in the first-stage power grid to be turned off is equal to a second time corresponding to determining that the fault point is in the second-stage power grid to controlling the switching module in the second-stage power grid to be turned off.
3. The power system according to claim 2, further comprising a voltage detection module in each stage of the power grid, wherein the voltage detection module is electrically connected with the control module, and the voltage detection module is used for detecting a bus voltage of the power grid at the stage;
the control module is used for determining that the fault point is in the first-stage power grid when the current detected by the current detection module in the first-stage power grid is greater than a preset current threshold value and the bus voltage of the second-stage power grid is 0 and the bus voltage of the first-stage power grid is reduced and is greater than 0;
the control module is further configured to determine that the fault point is in the second-stage power grid when the current detected by the current detection module in the second-stage power grid is greater than the preset current threshold, the bus voltage of the second-stage power grid decreases and is greater than 0, and the degree of decrease of the bus voltage of the first-stage power grid is less than the degree of decrease of the bus voltage of the second-stage power grid.
4. The power system of claim 1, wherein the control module comprises an input unit, a control unit, and an output unit, the input unit being electrically connected to the current detection module for collecting the current detected by the current detection module; the control unit is respectively and electrically connected with the input unit and the output unit, and is used for determining the fault point according to the current and outputting a control signal to the switch module of the power grid of the stage where the fault point is located through the output unit so as to control the switch module to be disconnected.
5. The power system of any of claims 1-4, wherein the current detection module comprises a current transformer and the switch module comprises a circuit breaker; the fault points include short circuit fault points.
6. A control method of an electric power system, characterized by comprising:
determining a fault point according to the current detected by the current detection module, and controlling a switch module to be disconnected in a power grid of a stage where the fault point is located;
and from determining the fault point to controlling the switching module to be disconnected in the power grid of the stage where the fault point is located, the time is less than the preset time.
7. The method of controlling a power system according to claim 1, wherein at least two stages of the power grids include a first stage power grid and a second stage power grid, the second stage power grid being a lower stage power grid of the first stage power grid;
determining a fault point according to the current detected by the current detection module, and controlling a switch module to be disconnected in a power grid of a stage where the fault point is located, wherein the method comprises the following steps:
when the fault point is determined to be in the first-stage power grid, the switch module in the first-stage power grid is controlled to be disconnected; when the fault point is determined to be in the second-stage power grid, the switch module of the second-stage power grid is controlled to be disconnected;
wherein a first time from determining that the fault point is in the first-stage power grid to controlling the switching module in the first-stage power grid to be turned off is equal to a second time corresponding to determining that the fault point is in the second-stage power grid to controlling the switching module in the second-stage power grid to be turned off.
8. The method according to claim 7, wherein the control module determines a fault point according to the current detected by the current detection module, and controls the switching module to be turned off in the power grid of the stage where the fault point is located, comprising:
at least when the current detected by the current detection module in the first-stage power grid is larger than a preset current threshold value, determining that the fault point is in the first-stage power grid, and controlling the switch module in the first-stage power grid to be disconnected;
and at least when the current detected by the current detection module in the second-stage power grid is larger than a preset current threshold value, determining that the fault point is in the second-stage power grid, and controlling the switch module in the second-stage power grid to be disconnected.
9. The method of claim 8, wherein determining that the fault point is on the second-stage power grid and controlling the switching module in the second-stage power grid to open at least when the current detected by the current detection module in the second-stage power grid is greater than a preset current threshold comprises:
when the current detected by the current detection module in the first-stage power grid and the current detected by the current detection module in the second-stage power grid are both greater than the preset current threshold, determining that the fault point is in the second-stage power grid, and controlling the switch module in the second-stage power grid to be disconnected;
after the switch module in the second-stage power grid is disconnected, the current detected by the current detection module in the first-stage power grid is kept larger than the preset current threshold value, the fault point is determined to be still in the first-stage power grid, and the switch module in the first-stage power grid is controlled to be disconnected.
10. The method of claim 8, further comprising a voltage detection module in each of the power grids; determining a fault point according to the current detected by the current detection module, and controlling a switch module to be disconnected in a power grid of a stage where the fault point is located, wherein the method comprises the following steps:
when the current detected by the current detection module in the first-stage power grid is greater than the preset current threshold value and the bus voltage of the second-stage power grid is 0, determining that the fault point is in the first-stage power grid and controlling the switch module in the first-stage power grid to be disconnected when the bus voltage of the first-stage power grid is reduced and is greater than 0;
and when the current detected by the current detection module in the second-stage power grid is larger than the preset current threshold value, the bus voltage of the second-stage power grid is reduced and larger than 0, and the reduction degree of the bus voltage of the first-stage power grid is smaller than that of the second-stage power grid, determining that the fault point is in the second-stage power grid, and controlling the switch module in the first-stage power grid to be disconnected.
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| CN202311429085.0A CN117458412A (en) | 2023-10-30 | 2023-10-30 | Electric power system and control method thereof |
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| CN202311429085.0A CN117458412A (en) | 2023-10-30 | 2023-10-30 | Electric power system and control method thereof |
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