Intelligent secondary voltage line selection device and implementation method thereof

Abstract

The invention provides an intelligent secondary voltage line selection device, which is installed in a PT interface screen, is connected with all voltage control loops in a measuring group and a metering group, is also connected with an air switch on each connected voltage control loop, and comprises a voltage acquisition module, an outlet module and a CPU module, the voltage acquisition module acquires secondary voltages on all the voltage control loops in real time and uploads the secondary voltages; the CPU module judges that the voltage control loops of the petroleum are abnormal according to the secondary voltages of all the voltage control loops, and if the voltage control loops are abnormal, each abnormal voltage control loop and a fault phase thereof are converted into a control instruction to be issued to the outlet module; and the outlet module controls the air switch on each abnormal voltage control loop according to the control instruction so as to turn off the fault phase output voltage on each abnormal voltage control loop. According to the invention, the scientific rationality of connection and use of the voltage control loop can be improved, and large-area power failure caused by protection misoperation due to non-protection voltage accidents can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid fault detection, and in particular to an intelligent secondary voltage line selection device and an implementation method thereof. Background Art

[0002] In recent years, there have been many non-accidental tripping events in the power system caused by the loss of secondary voltage, which has led to malfunction of protection and affected the stability of the power grid. The main reason is the unreasonable design and wiring of the secondary voltage in the substation. At present, there are only three groups of secondary windings in the primary voltage transformer CT winding in the substation, namely the protection group, the measurement group and the metering group. Therefore, the voltage connected to the PT interface panel is also only the protection group voltage, the measurement group voltage and the metering group voltage. Among them, the protection group voltage includes the bus differential protection voltage, the line protection voltage and the main transformer protection voltage; the measurement group voltage includes the line measurement and control voltage, the main transformer measurement and control voltage, the fault recording voltage, the detuning device voltage, the signal relay voltage and the voltage monitoring voltage; the metering group voltage includes the line meter voltage, the main transformer meter voltage and the power quality voltage.

[0003] However, in actual work, loop design defects can cause secondary voltage loss, thus affecting the safe and stable operation of the power grid. For example, during the operation of the 110kV line busbar switch, a high-frequency voltage is generated, which resonates with the secondary detuning device, amplifying the high-frequency component and causing the secondary voltage circuit breaker to trip. However, since the detuning device is connected to the protection group voltage, once the loop design is defective, the secondary voltage of the protection will lose voltage, resulting in the 110kV backup automatic switch malfunctioning.

[0004] In summary, in order to scientifically and rationally improve the voltage control circuit, it is necessary to develop an intelligent secondary voltage line selection device, which can improve the scientific rationality of the access and use of the voltage control circuit, and avoid large-scale power outages caused by false protection operations due to non-protective voltage accidents. Summary of the invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide an intelligent secondary voltage line selection device and an implementation method thereof, which can improve the scientific rationality of voltage control loop access and use, and avoid large-scale power outages caused by protection malfunctions due to non-protective voltage accidents.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides an intelligent secondary voltage line selection device, which is installed in a PT interface panel preset with a protection group voltage control loop, a measurement group voltage control loop and a metering group voltage control loop, and is connected to the measurement group voltage control loop and all voltage control loops contained in the metering group voltage control loop, and is also connected to each connected voltage control loop preset for turning on or off the corresponding secondary voltage three-phase output circuit breaker, including a voltage acquisition module, an export module and a CPU module; wherein,

[0007] One end of the voltage acquisition module is connected to the measurement group voltage control loop and all the voltage control loops included in the metering group voltage control loop, and the other end is connected to the first end of the CPU module, and is used to collect the secondary voltage outputted by the measurement group voltage control loop and all the voltage control loops included in the metering group voltage control loop in real time, and upload it to the CPU module;

[0008] The second end of the CPU module is connected to one end of the export module, and is used to determine whether there is at least one voltage control loop abnormality according to the secondary voltages output by all voltage control loops included in the voltage control loop of the measurement group and the voltage control loop of the metering group collected by the voltage collection module, and when it is determined that one or more voltage control loops are abnormal, determine each abnormal voltage control loop and its fault phase, and further convert each abnormal voltage control loop and its fault phase into a corresponding control instruction and send it to the export module;

[0009] The other end of the export module is connected to the circuit breakers on all the voltage control loops contained in the measurement group voltage control loop and the metering group voltage control loop, and is used to control the circuit breakers on each abnormal voltage control loop according to the control instructions issued by the CPU module, so as to shut off the faulty phase output voltage corresponding to each abnormal voltage control loop.

[0010] Among them, it also includes: recording and alarm module; among them,

[0011] The recording and alarm module is connected to the third end of the CPU module, and is used to store the secondary voltages output by all voltage control loops contained in the voltage control loop of the measurement group and the voltage control loop of the metering group collected by the voltage collection module, and store the judgment results and control instructions of the CPU module; and,

[0012] If an alarm signal is received which is synchronously generated by the CPU module when converting any control instruction, an alarm is issued.

[0013] Among them, the measurement group voltage control circuit includes a line measurement and control voltage control circuit, a main transformer measurement and control voltage control circuit, a fault recording voltage control circuit, a harmonic elimination device voltage control circuit, a signal relay voltage control circuit and a voltage monitoring control circuit.

[0014] Among them, the metering group voltage control circuit includes a line watt-hour meter voltage control circuit, a main transformer watt-hour meter voltage control circuit and a power quality voltage control circuit.

[0015] The CPU module determines the abnormal voltage control loop and its fault phase by outputting each phase voltage or / and the potential difference between any two phase voltages on the secondary voltage of all voltage control loops;

[0016] If the CPU module determines that the voltage of any phase among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the first voltage lower limit value or greater than the first voltage upper limit value, the voltage control loop is determined to be an abnormal voltage control loop with a single-phase fault, and the phase line in the voltage control loop whose voltage is less than the first voltage lower limit value or greater than the first voltage upper limit value is determined to be a faulty phase;

[0017] If the CPU module determines that the potential difference between any two phase voltages among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the second voltage lower limit or greater than the second voltage upper limit, it determines that the voltage control loop is an abnormal voltage control loop with a phase-to-phase fault, and determines that the two phase lines in the voltage control loop with a potential difference less than the second voltage lower limit or greater than the second voltage upper limit are both faulty phases.

[0018] The embodiment of the present invention also provides a method for realizing an intelligent secondary voltage line selection device, which is realized on an intelligent secondary voltage line selection device installed in a PT interface panel; wherein the PT interface panel is also preset with a protection group voltage control loop, a measurement group voltage control loop and a metering group voltage control loop; the intelligent secondary voltage line selection device is connected to the measurement group voltage control loop and all voltage control loops contained in the metering group voltage control loop, and is also connected to a circuit breaker preset on each connected voltage control loop for turning on or off the corresponding secondary voltage three-phase output; the method comprises the following steps:

[0019] Real-time acquisition of the secondary voltage outputted by the voltage control loop of the measurement group and all the voltage control loops included in the voltage control loop of the metering group;

[0020] Based on the collected secondary voltages output by all the voltage control loops included in the voltage control loop of the measurement group and the metering group, it is determined whether at least one voltage control loop is abnormal, and when it is determined that one or more voltage control loops are abnormal, each abnormal voltage control loop and its fault phase are determined, and further converted into corresponding control instructions based on each abnormal voltage control loop and its fault phase;

[0021] According to the control instruction, the circuit breaker on each abnormal voltage control loop is controlled to shut down the output voltage of the fault phase corresponding to each abnormal voltage control loop.

[0022] Wherein, the method further comprises:

[0023] Storing the collected secondary voltages output by the measurement group voltage control loop and all the voltage control loops included in the metering group voltage control loop, as well as storing the determination results and control instructions; and,

[0024] If an alarm signal generated synchronously based on the conversion of any control instruction is received, an alarm is issued.

[0025] Among them, the measurement group voltage control circuit includes a line measurement and control voltage control circuit, a main transformer measurement and control voltage control circuit, a fault recording voltage control circuit, a harmonic elimination device voltage control circuit, a signal relay voltage control circuit and a voltage monitoring control circuit.

[0026] Among them, the metering group voltage control circuit includes a line watt-hour meter voltage control circuit, a main transformer watt-hour meter voltage control circuit and a power quality voltage control circuit.

[0027] Wherein, the method further comprises:

[0028] The abnormal voltage control loop and its fault phase are determined by measuring the potential difference between each phase voltage or / and any two phase voltages on the output secondary voltage of all voltage control loops; wherein,

[0029] If it is determined that the voltage of any phase among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the first voltage lower limit value or greater than the first voltage upper limit value, the voltage control loop is determined to be an abnormal voltage control loop with a single-phase fault, and the phase line in the voltage control loop whose voltage is less than the first voltage lower limit value or greater than the first voltage upper limit value is determined to be the faulty phase;

[0030] If it is determined that the potential difference between any two phases of the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the second voltage lower limit or greater than the second voltage upper limit, then the voltage control loop is determined to be an abnormal voltage control loop with a phase-to-phase fault, and it is determined that the two phase lines in the voltage control loop with a potential difference less than the second voltage lower limit or greater than the second voltage upper limit are both faulty phases.

[0031] The implementation of the embodiments of the present invention has the following beneficial effects:

[0032] The intelligent secondary voltage line selection device of the present invention is based on the secondary voltage output by all voltage control loops contained in the voltage control loop of the measurement group and the voltage control loop of the metering group in the PT interface panel, and determines whether there is at least one voltage control loop abnormal. If so, each abnormal voltage control loop and its fault phase are determined, and further converted into control instructions to control the circuit breakers on all abnormal voltage control loops to shut off the output voltages of the corresponding fault phases on all abnormal voltage control loops, thereby improving the scientific rationality of the access and use of the voltage control loop and avoiding large-scale power outages caused by malfunction of protection due to non-protective voltage accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0034] Figure 1 A schematic diagram of the system structure of an intelligent secondary voltage line selection device provided by an embodiment of the present invention;

[0035] Figure 2 An application scenario diagram of an intelligent secondary voltage line selection device provided by an embodiment of the present invention;

[0036] Figure 3 The present invention provides a flowchart of a method for implementing an intelligent secondary voltage line selection device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0038] like Figure 1As shown, an intelligent secondary voltage line selection device is proposed in an embodiment of the present invention, which is installed in a PT interface panel (not shown) preset with a protection group voltage control circuit, a measurement group voltage control circuit and a metering group voltage control circuit, and is connected to the measurement group voltage control circuit and all voltage control circuits (not shown) contained in the metering group voltage control circuit, and is also connected to each connected voltage control circuit preset to turn on or off the corresponding secondary voltage three-phase output circuit breaker (or voltage connecting piece, not shown). Among them, the measurement group voltage control circuit includes but is not limited to the line measurement and control voltage control circuit, the main transformer measurement and control voltage control circuit, the fault recording voltage control circuit, the detuning device voltage control circuit, the signal relay voltage control circuit and the voltage monitoring control circuit, etc.; the metering group voltage control circuit includes but is not limited to the line watt-hour meter voltage control circuit, the main transformer watt-hour meter voltage control circuit and the power quality voltage control circuit, etc.

[0039] At this time, the intelligent secondary voltage line selection device includes a voltage acquisition module 1, an export module 3 and a CPU module 2; wherein,

[0040] One end of the voltage acquisition module 1 is connected to all the voltage control loops included in the voltage control loop of the measurement group and the voltage control loop of the metering group, and the other end is connected to the first end of the CPU module 2, and is used to collect the secondary voltage outputted from all the voltage control loops included in the voltage control loop of the measurement group and the voltage control loop of the metering group in real time, and upload it to the CPU module 2;

[0041] The second end of the CPU module 2 is connected to one end of the export module 3, and is used to determine whether there is at least one voltage control loop abnormality based on the secondary voltages output by all the voltage control loops included in the voltage control loop of the measurement group and the voltage control loop of the metering group collected by the voltage acquisition module 1, and when it is determined that one or more voltage control loops are abnormal, each abnormal voltage control loop and its fault phase are determined, and each abnormal voltage control loop and its fault phase are further converted into corresponding control instructions and sent to the export module 2; it should be noted that the CPU module 2 determines the abnormal voltage control loop and its fault phase by outputting each phase voltage or / and the potential difference between any two phase voltages on the secondary voltage of all voltage control loops; wherein, the CPU If module 2 determines that the voltage of any phase among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the first voltage lower limit value or greater than the first voltage upper limit value, then the voltage control loop is determined to be an abnormal voltage control loop with a single-phase fault, and the phase line with a voltage less than the first voltage lower limit value or greater than the first voltage upper limit value in the voltage control loop is determined to be a faulty phase; or, if CPU module 2 determines that the potential difference between the voltages of any two phases among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the second voltage lower limit value or greater than the second voltage upper limit value, then the voltage control loop is determined to be an abnormal voltage control loop with a phase-to-phase fault, and the two phase lines with a potential difference less than the second voltage lower limit value or greater than the second voltage upper limit value in the voltage control loop are determined to be faulty phases;

[0042] The other end of the outlet module 3 is connected to the circuit breakers on all the voltage control loops included in the voltage control loop of the measuring group and the voltage control loop of the metering group, and is used to control the circuit breakers on each abnormal voltage control loop according to the control instructions issued by the CPU module 2, so as to shut off the output voltage of the fault phase corresponding to each abnormal voltage control loop. It should be noted that the circuit breaker can be flexibly designed according to the actual situation, and it can be considered that each of the ABC phases of the secondary voltage is provided with a circuit breaker or each of the ABC phases is provided with a circuit breaker.

[0043] It can be understood that, considering that when the protection group voltage (i.e., the secondary voltage output on the protection group voltage control loop) is abnormal, the protection device makes a judgment to isolate and remove the fault. Therefore, the intelligent secondary voltage line selection device of the present invention can also perform real-time voltage monitoring through the voltage acquisition module 1, but there is no need to isolate and remove the fault of the protection group voltage control loop through the export module 3.

[0044] In an embodiment of the present invention, the intelligent secondary voltage line selection device further includes: a recording and alarm module 4; wherein the recording and alarm module 4 is connected to the third end of the CPU module 2, and is used to store the secondary voltages output by all voltage control loops contained in the voltage control loop of the measurement group and the voltage control loop of the metering group collected by the voltage collection module 1, and to store the judgment results and control instructions of the CPU module 2; and,

[0045] If an alarm signal is received which is synchronously generated by the CPU module 2 based on the conversion of any control instruction, an alarm is issued.

[0046] like Figure 2 As shown, the application scenario of an intelligent secondary voltage line selection device proposed in an embodiment of the present invention is further described as follows:

[0047] To solve the hidden dangers of the secondary voltage circuit of the substation, the intelligent secondary voltage line selection device of the present invention is added to the PT interface panel. When the intelligent secondary voltage line selection device of the present invention is connected to the voltage control circuit of the parallel access protection group, measurement group and metering group in the PT interface panel, the priority is set to 1, 2, and 3 levels accordingly.

[0048] When the voltage control circuit of the measurement group and metering group is short-circuited due to reasons other than system and human error, the voltage control circuit can be cut off and isolated according to the priority, and the fault phase voltage can be isolated at the same time. The specific device structure is as follows Figure 2 shown.

[0049] At this time, when the secondary voltage output on the voltage control loop of the measurement group or metering group is abnormal, the intelligent secondary voltage line selection device of the present invention can quickly isolate the faulty phase of the abnormal voltage control loop according to the set value and logic performed by the CPU module 2, and record the problem at the same time, so as to facilitate the operation and maintenance personnel to search and handle it, and send out alarm information to notify the main station personnel.

[0050] When the voltage of the protection group (i.e., the secondary voltage output on the protection group voltage control loop) is abnormal, the logic ends and the protection device makes a judgment to isolate and remove the fault. When the voltage of the non-protection group (i.e., the secondary voltage output on the measurement group or metering group voltage control loop) is abnormal, it can be judged whether the fault phase is single-phase or double-phase, and the protection action is selected by comparison, and the fault phase voltage is isolated through the outlet module 3. At the same time, the intelligent secondary voltage line selection device of the present invention collects all voltages again. When the system voltage returns to normal, the logic ends, otherwise the line selection logic continues to remove the fault voltage.

[0051] It should be noted that the set value of the CPU module 2 can be flexibly adjusted according to actual conditions, including voltage threshold, percentage threshold, etc., so that there are many types of set value comparisons, which will not be repeated here.

[0052] like Figure 3 As shown, an implementation method of an intelligent secondary voltage line selection device proposed in an embodiment of the present invention is implemented on an intelligent secondary voltage line selection device installed in a PT interface panel; wherein the PT interface panel is also preset with a protection group voltage control loop, a measurement group voltage control loop and a metering group voltage control loop; the intelligent secondary voltage line selection device is connected to the measurement group voltage control loop and all voltage control loops contained in the metering group voltage control loop, and is also connected to each circuit breaker preset on the connected voltage control loop for turning on or off the corresponding secondary voltage three-phase output; the method comprises the following steps:

[0053] Step S1, collecting in real time the secondary voltage outputted by the voltage control loop of the measurement group and all the voltage control loops included in the voltage control loop of the metering group;

[0054] Step S2: judging whether there is at least one voltage control loop abnormality according to the collected secondary voltages output by all the voltage control loops included in the voltage control loop of the measurement group and the voltage control loop of the metering group, and when it is determined that one or more voltage control loops are abnormal, determining each abnormal voltage control loop and its fault phase, and further converting each abnormal voltage control loop and its fault phase into a corresponding control instruction;

[0055] Step S3: According to the control instruction, the circuit breaker on each abnormal voltage control loop is controlled to shut down the output voltage of the fault phase corresponding to each abnormal voltage control loop.

[0056] Wherein, the method further comprises:

[0057] Storing the collected secondary voltages output by the measurement group voltage control loop and all the voltage control loops included in the metering group voltage control loop, as well as storing the determination results and control instructions; and,

[0058] If an alarm signal generated synchronously based on the conversion of any control instruction is received, an alarm is issued.

[0059] Among them, the measurement group voltage control circuit includes a line measurement and control voltage control circuit, a main transformer measurement and control voltage control circuit, a fault recording voltage control circuit, a harmonic elimination device voltage control circuit, a signal relay voltage control circuit and a voltage monitoring control circuit.

[0060] Among them, the metering group voltage control circuit includes a line watt-hour meter voltage control circuit, a main transformer watt-hour meter voltage control circuit and a power quality voltage control circuit.

[0061] Wherein, the method further comprises:

[0062] The abnormal voltage control loop and its fault phase are determined by measuring the potential difference between each phase voltage or / and any two phase voltages on the output secondary voltage of all voltage control loops; wherein,

[0063] If it is determined that the voltage of any phase among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the first voltage lower limit value or greater than the first voltage upper limit value, the voltage control loop is determined to be an abnormal voltage control loop with a single-phase fault, and the phase line in the voltage control loop whose voltage is less than the first voltage lower limit value or greater than the first voltage upper limit value is determined to be the faulty phase;

[0064] If it is determined that the potential difference between any two phases of the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the second voltage lower limit or greater than the second voltage upper limit, then the voltage control loop is determined to be an abnormal voltage control loop with a phase-to-phase fault, and it is determined that the two phase lines in the voltage control loop with a potential difference less than the second voltage lower limit or greater than the second voltage upper limit are both faulty phases.

[0065] The implementation of the embodiments of the present invention has the following beneficial effects:

[0066] The intelligent secondary voltage line selection device of the present invention is based on the secondary voltage output by all voltage control loops contained in the voltage control loop of the measurement group and the voltage control loop of the metering group in the PT interface panel, and determines whether there is at least one voltage control loop abnormal. If so, each abnormal voltage control loop and its fault phase are determined, and further converted into control instructions to control the circuit breakers on all abnormal voltage control loops to shut off the output voltages of the corresponding fault phases on all abnormal voltage control loops, thereby improving the scientific rationality of the access and use of the voltage control loop and avoiding large-scale power outages caused by malfunction of protection due to non-protective voltage accidents.

[0067] It is worth noting that in the above-mentioned device embodiment, the various device modules included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be realized; in addition, the specific names of the various functional modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0068] A person skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, CD-ROM, etc.

[0069] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. An intelligent secondary voltage line selection device, characterized in that: It is installed in a PT interface panel preset with a protection group voltage control circuit, a measurement group voltage control circuit and a metering group voltage control circuit, and is connected to the measurement group voltage control circuit and all voltage control circuits contained in the metering group voltage control circuit, and is also connected to the circuit breaker preset on each connected voltage control circuit for turning on or off the corresponding secondary voltage three-phase output, including a voltage acquisition module, an export module and a CPU module; wherein, One end of the voltage acquisition module is connected to the measurement group voltage control loop and all the voltage control loops included in the metering group voltage control loop, and the other end is connected to the first end of the CPU module, and is used to collect the secondary voltage outputted by the measurement group voltage control loop and all the voltage control loops included in the metering group voltage control loop in real time, and upload it to the CPU module; The second end of the CPU module is connected to one end of the export module, and is used to determine whether there is at least one voltage control loop abnormality according to the secondary voltages output by all voltage control loops included in the voltage control loop of the measurement group and the voltage control loop of the metering group collected by the voltage collection module, and when it is determined that one or more voltage control loops are abnormal, determine each abnormal voltage control loop and its fault phase, and further convert each abnormal voltage control loop and its fault phase into a corresponding control instruction and send it to the export module; The other end of the export module is connected to the circuit breakers on all the voltage control loops contained in the measurement group voltage control loop and the metering group voltage control loop, and is used to control the circuit breakers on each abnormal voltage control loop according to the control instructions issued by the CPU module, so as to shut off the faulty phase output voltage corresponding to each abnormal voltage control loop.

2. The intelligent secondary voltage line selection device according to claim 1, characterized in that: Also includes: Recording and alarm module; among them, The recording and alarm module is connected to the third end of the CPU module, and is used to store the secondary voltages output by all voltage control loops contained in the voltage control loop of the measurement group and the voltage control loop of the metering group collected by the voltage collection module, and store the judgment results and control instructions of the CPU module; and, If an alarm signal is received which is synchronously generated by the CPU module when converting any control instruction, an alarm is issued.

3. The intelligent secondary voltage line selection device according to claim 1, characterized in that: The voltage control circuit of the measurement group includes a line measurement and control voltage control circuit, a main transformer measurement and control voltage control circuit, a fault recording voltage control circuit, a harmonic elimination device voltage control circuit, a signal relay voltage control circuit and a voltage monitoring control circuit.

4. The intelligent secondary voltage line selection device according to claim 1, characterized in that: The voltage control circuit of the metering group includes a line watt-hour meter voltage control circuit, a main transformer watt-hour meter voltage control circuit and a power quality voltage control circuit.

5. The intelligent secondary voltage line selection device according to claim 1, characterized in that: The CPU module determines the abnormal voltage control loop and its fault phase by outputting each phase voltage or / and the potential difference between any two phase voltages on the secondary voltage of all voltage control loops; wherein, If the CPU module determines that the voltage of any phase among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the first voltage lower limit value or greater than the first voltage upper limit value, the voltage control loop is determined to be an abnormal voltage control loop with a single-phase fault, and the phase line in the voltage control loop whose voltage is less than the first voltage lower limit value or greater than the first voltage upper limit value is determined to be a faulty phase; If the CPU module determines that the potential difference between any two phase voltages among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the second voltage lower limit or greater than the second voltage upper limit, it determines that the voltage control loop is an abnormal voltage control loop with a phase-to-phase fault, and determines that the two phase lines in the voltage control loop with a potential difference less than the second voltage lower limit or greater than the second voltage upper limit are both faulty phases.

6. A method for implementing an intelligent secondary voltage line selection device, characterized in that: It is implemented on an intelligent secondary voltage line selection device installed in a PT interface panel; wherein the PT interface panel is also preset with a protection group voltage control circuit, a measurement group voltage control circuit and a metering group voltage control circuit; the intelligent secondary voltage line selection device is connected to the measurement group voltage control circuit and all voltage control circuits contained in the metering group voltage control circuit, and is also connected to each connected voltage control circuit preset to turn on or off the corresponding secondary voltage three-phase output circuit breaker; the method comprises the following steps: Real-time acquisition of the secondary voltage outputted by the voltage control loop of the measurement group and all the voltage control loops included in the voltage control loop of the metering group; Based on the collected secondary voltages output by all the voltage control loops included in the voltage control loop of the measurement group and the metering group, it is determined whether at least one voltage control loop is abnormal, and when it is determined that one or more voltage control loops are abnormal, each abnormal voltage control loop and its fault phase are determined, and further converted into corresponding control instructions based on each abnormal voltage control loop and its fault phase; According to the control instruction, the circuit breaker on each abnormal voltage control loop is controlled to shut down the output voltage of the fault phase corresponding to each abnormal voltage control loop.

7. The method for implementing the intelligent secondary voltage line selection device according to claim 6, characterized in that: The method further comprises: Storing the collected secondary voltages output by the measurement group voltage control loop and all the voltage control loops included in the metering group voltage control loop, as well as storing the determination results and control instructions; and, If an alarm signal generated synchronously based on the conversion of any control instruction is received, an alarm is issued.

8. The method for implementing the intelligent secondary voltage line selection device according to claim 6, characterized in that: The voltage control circuit of the measurement group includes a line measurement and control voltage control circuit, a main transformer measurement and control voltage control circuit, a fault recording voltage control circuit, a harmonic elimination device voltage control circuit, a signal relay voltage control circuit and a voltage monitoring control circuit.

9. The method for implementing the intelligent secondary voltage line selection device according to claim 6, characterized in that: The voltage control circuit of the metering group includes a line watt-hour meter voltage control circuit, a main transformer watt-hour meter voltage control circuit and a power quality voltage control circuit.

10. The method for implementing the intelligent secondary voltage line selection device according to claim 6, characterized in that: The method further comprises: The abnormal voltage control loop and its fault phase are determined by measuring the potential difference between each phase voltage or / and any two phase voltages on the output secondary voltage of all voltage control loops; wherein, If it is determined that the voltage of any phase among the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the first voltage lower limit value or greater than the first voltage upper limit value, the voltage control loop is determined to be an abnormal voltage control loop with a single-phase fault, and the phase line in the voltage control loop whose voltage is less than the first voltage lower limit value or greater than the first voltage upper limit value is determined to be the faulty phase; If it is determined that the potential difference between any two phases of the three phases ABC on the secondary voltage output by a certain voltage control loop is less than the second voltage lower limit or greater than the second voltage upper limit, then the voltage control loop is determined to be an abnormal voltage control loop with a phase-to-phase fault, and it is determined that the two phase lines in the voltage control loop with a potential difference less than the second voltage lower limit or greater than the second voltage upper limit are both faulty phases.

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