CN116885857B - Power grid voltage intelligent monitoring system based on dynamic voltage restorer - Google Patents
Power grid voltage intelligent monitoring system based on dynamic voltage restorer Download PDFInfo
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- CN116885857B CN116885857B CN202311147680.5A CN202311147680A CN116885857B CN 116885857 B CN116885857 B CN 116885857B CN 202311147680 A CN202311147680 A CN 202311147680A CN 116885857 B CN116885857 B CN 116885857B
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- 238000012544 monitoring process Methods 0.000 title claims abstract description 40
- 238000011156 evaluation Methods 0.000 claims abstract description 40
- 238000001514 detection method Methods 0.000 claims abstract description 33
- 238000005520 cutting process Methods 0.000 claims abstract description 5
- 238000004146 energy storage Methods 0.000 claims description 59
- 238000000034 method Methods 0.000 claims description 14
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- 238000010248 power generation Methods 0.000 claims description 6
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- 230000002159 abnormal effect Effects 0.000 abstract description 2
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention relates to the field of electric energy quality control, in particular to a power grid voltage intelligent monitoring system based on a dynamic voltage restorer, which comprises a power supply end used for supplying electric energy, a power supply power grid used for conveying the electric energy, a load end used for using the electric energy, a dynamic voltage restorer used for cutting off the power supply power grid and supplying power to the load end when the power supply voltage is abnormal, a detection module used for detecting information of system operation, a central control module used for obtaining a voltage compensation evaluation value according to the information of system operation and judging whether the operation of the dynamic voltage restorer meets a preset standard according to the voltage compensation evaluation value, and an adjusting module used for adjusting corresponding operation parameters in the system to corresponding values according to an instruction output by the central control module.
Description
Technical Field
The invention relates to the field of electric energy quality control, in particular to a power grid voltage intelligent monitoring system based on a dynamic voltage restorer.
Background
Voltage quality is one of the important indicators of power quality, which plays an important role in ensuring safe and stable operation of the power system.
Chinese patent publication No.: CN106451410B discloses a direct current dynamic voltage restorer and a restoring method, comprising a detecting unit for detecting the load voltage of the previous K beats of the load; the control unit is respectively connected with the detection unit and the energy storage unit and is used for judging whether to carry out voltage compensation on the load according to the load voltage, determining a compensation voltage value according to the load voltage after determining to carry out voltage compensation on the load, and sending a control signal representing the compensation voltage value to the energy storage unit; the energy storage unit is connected with the direct current power distribution network and is used for outputting direct current voltage corresponding to the compensation voltage value according to the control signal. It can be seen that the above-mentioned provides accurate voltage compensation when the monitored voltage changes, but weak points and fault occurrence in the power system cannot be found in time.
Disclosure of Invention
Therefore, the invention provides a power grid voltage intelligent monitoring system based on a dynamic voltage restorer, which is used for overcoming the defect that weak points and fault occurrence conditions in a power system cannot be found in time in the prior art.
In order to achieve the above object, the present invention provides a power grid voltage intelligent monitoring system based on a dynamic voltage restorer, comprising:
a power supply terminal including a power generation device for generating electric power and a transformer for adjusting a voltage of the electric power output from the power generation device;
the power supply grid is connected with the power supply end and used for conveying electric energy output by the power supply end;
the load end is connected with the power supply grid and comprises a plurality of electric equipment used for receiving and using the electric energy transmitted by the power supply grid;
the dynamic voltage restorer is arranged on the power supply network and is respectively connected with the power supply end and the load end through the power supply network, and comprises a switch for cutting off the power supply network when the power supply voltage is unstable, an energy storage device for supplying power to the load end after the power supply network is disconnected, and an inverter device arranged between the energy storage device and the load end for converting direct current output by the energy storage device into alternating current;
the detection module is respectively connected with the power supply end, the power supply grid, the load end and the dynamic voltage restorer and is used for detecting information of system operation;
the central control module is connected with the detection module and is used for judging whether the operation of the dynamic voltage restorer accords with the standard according to the information detected by the detection module, determining whether the operation of the dynamic voltage restorer accords with the preset standard according to the discharge voltage of the energy storage device when the operation of the dynamic voltage restorer is primarily judged to be not in accordance with the standard, or determining the reason of unstable voltage of the power supply grid according to the difference value of the power supply power and the load power; the central control module generates a corresponding instruction according to the determined reason when the determination of the reason for the unstable voltage of the power supply grid is completed;
and the adjusting module is connected with the central control module, the power supply end and the dynamic voltage restorer and is used for adjusting the corresponding operation parameters in the system to the corresponding values according to the instructions output by the central control module.
Further, the central control module determines, according to the voltage compensation evaluation value E, whether the operation of the dynamic voltage restorer meets a determination mode of a preset standard or not under a first preset condition, and setsWherein->For the evaluation factor ∈ ->T is the highest temperature value of the energy storage device during single voltage compensation, T is the duration value of the single voltage compensation, n is the residual capacity of the energy storage device after the single voltage compensation, n is (0, 1), the central control module judges that the operation of the dynamic voltage restorer does not accord with a preset standard when the voltage compensation evaluation value E is more than or equal to a first preset voltage compensation evaluation value, and judges whether the operation of the dynamic voltage restorer accords with the preset standard according to the measured discharge voltage of the energy storage device when the voltage compensation evaluation value E is less than a second preset voltage compensation evaluation value, or determines the reason of the unstable voltage of the power supply grid according to the difference value of the power supply power of the power supply end before the voltage compensation and the load power of the load end before the voltage compensation, which is measured by the detection module when the voltage compensation evaluation value E is more than or equal to the second preset voltage compensation evaluation value;
the first preset condition is that the dynamic voltage restorer completes single voltage compensation for a system.
Further, the central control module performs secondary judgment on whether the operation of the dynamic voltage restorer accords with a preset standard according to the discharge voltage measured by the detection module under a second preset condition, and controls the adjustment module to expand the capacity of the energy storage device to a corresponding value according to the difference value between a first preset discharge voltage and the measured discharge voltage when the operation of the dynamic voltage restorer is judged to be not in accordance with the standard, or controls the adjustment module to reduce the initial compensation voltage in the voltage compensation process to the corresponding value according to the difference value between the measured discharge voltage and the first preset discharge voltage;
the central control module controls the regulating module to expand the capacity of the energy storage device when the discharge voltage is smaller than the first preset discharge voltage, or controls the regulating module to reduce the initial compensation voltage value when the discharge voltage is larger than or equal to the first preset discharge voltage and smaller than a second preset discharge voltage;
and the second preset condition is that the central control module carries out secondary judgment on whether the operation of the dynamic voltage restorer accords with a preset standard.
Further, the central control module is provided with a plurality of capacity expansion adjusting modes aiming at the capacity of the energy storage device under a third preset condition, and the capacities of the energy storage devices adjusted by the adjusting modes are different;
the third preset condition is that the central control module controls the adjusting module to expand the capacity of the energy storage device to a corresponding value according to the difference value between the first preset discharge voltage and the measured discharge voltage.
Further, the central control module is provided with a plurality of voltage regulation modes aiming at initial compensation voltage in the voltage compensation process under a fourth preset condition, and the initial compensation voltages regulated by the regulation modes are different;
the fourth preset condition is that the central control module controls the adjusting module to reduce the initial compensation voltage in the voltage compensation process to a corresponding value according to the difference value between the measured discharge voltage and the first preset discharge voltage.
Further, the central control module selects a corresponding processing mode according to the determined reason of the unstable voltage of the power supply grid under a fifth preset condition, including:
when the voltage of the power supply network is unstable because the power consumption of the load end does not meet the preset standard, the rated power of the electric equipment in the load end is counted, the opening quantity of the electric equipment is limited according to the counted result,
when the voltage instability of the power supply grid is judged because the dynamic voltage restorer has hardware faults, the warning that the dynamic voltage restorer has hardware faults is sent out,
when the reason that the voltage of the power supply network is unstable is that the power supply of the power supply end does not meet the preset standard is judged, the central control module controls the detection module to detect the amplitude of the voltage fluctuation, and whether the power supply of the power supply end meets the preset standard is determined according to the detected amplitude of the voltage fluctuation;
the central control module judges that the power consumption of the load end does not meet a preset standard when the difference value of the power supply and the load power is smaller than zero, judges that the dynamic voltage restorer has hardware faults when the difference value of the power supply and the load power is equal to zero, and judges that the power supply of the power supply end does not meet the preset standard when the difference value of the power supply and the load power is larger than zero;
the fifth preset condition is that the central control module determines the reason for unstable voltage of the power supply grid according to the difference value of the power supply power and the load power.
Further, the central control module controls the detection module to detect the amplitude of voltage fluctuation under a sixth preset condition, and when the power supply of the power supply end is determined to be not in accordance with a preset standard according to the detected amplitude of voltage fluctuation, the central control module sends out a warning that the power of the transformer at the power supply end is not in accordance with the preset standard and needs to be replaced, and determines the power of the transformer to be replaced according to the difference between the amplitude of voltage fluctuation and the preset fluctuation amplitude;
the sixth preset condition is that the reason that the voltage of the power supply grid determined by the central control module is unstable is that the power supply end does not meet a preset standard.
Further, the central control module determines, under a seventh preset condition, a decision for a voltage compensation event level according to a determined cause of voltage instability of the power supply grid, including:
when the voltage of the power supply grid is unstable because the power consumption of the load end does not meet the preset standard, the voltage compensation event is judged to be a primary voltage compensation event,
when the voltage of the power supply network is unstable because the power supply end supplies power which does not meet the preset standard, judging that the voltage compensation event is a secondary voltage compensation event;
and the seventh preset condition is that the central control module completes the judgment of the reason of the unstable voltage of the power supply grid.
Further, the central control module controls the detection module to detect the frequency of unstable voltage of the power supply grid in the preset time under the eighth preset condition, judges whether the operation of the intelligent power supply grid voltage monitoring system does not meet the preset standard according to the detected frequency, counts voltage compensation event levels, and judges whether the operation of the intelligent power supply grid voltage monitoring system meets the preset standard or not according to the duty ratio of each level;
and the eighth preset condition is that the central control module completes the judgment of the voltage compensation event level.
Further, the central control module determines whether the operation of the power supply grid voltage intelligent monitoring system meets a secondary judgment of a preset standard according to the duty ratio of each level of voltage compensation event under a ninth preset condition, and increases the output voltage of the power supply end to a corresponding value according to the difference between the duty ratio of the primary voltage compensation event and the preset duty ratio when the operation of the power supply grid voltage intelligent monitoring system does not meet the preset standard, or increases the power energy capacity of the power supply end to a corresponding value according to the difference between the duty ratio of the secondary voltage compensation event and the preset duty ratio;
the central control module increases the output voltage of the power supply end to a corresponding value when the duty ratio of the primary voltage compensation event is larger than a preset duty ratio, and expands the power energy capacity of the power supply end to a corresponding value when the duty ratio of the secondary voltage compensation event is larger than the preset duty ratio;
and the ninth preset condition is that the central control module performs secondary judgment on whether the operation of the intelligent power supply grid voltage monitoring system meets a preset standard or not.
Compared with the prior art, the invention has the beneficial effects that: the invention comprises a power supply end for supplying electric energy, a power supply network for delivering electric energy, a load end for consuming electric energy, a dynamic voltage restorer for cutting off the power supply network and supplying power to the load end when the power supply voltage is abnormal, a detection module for detecting the information of system operation, a central control module for obtaining a voltage compensation evaluation value according to the information of system operation and judging whether the operation of the dynamic voltage restorer meets the preset standard according to the voltage compensation evaluation value, and an adjusting module for adjusting the corresponding operation parameters in the system to the corresponding values according to the result of the central control judgment, thereby improving the monitoring quality of the power grid voltage.
Further, the invention realizes the accurate judgment of whether the operation of the dynamic voltage restorer accords with the preset standard through the voltage compensation evaluation value, and determines whether the operation of the dynamic voltage restorer accords with the secondary judgment mode of the preset standard according to the discharge voltage of the energy storage device or determines the judgment mode of the cause of the unstable power grid voltage according to the difference value of the power supply power and the load power when the operation of the dynamic voltage restorer does not accord with the preset standard, thereby solving the monitoring of the operation state of the system after the voltage compensation is completed in the system.
Further, when the operation of the dynamic voltage restorer accords with the preset standard or not, whether the discharge voltage of the energy storage device drops in the compensation process or not is detected, and the capacity expansion of the energy storage device or the initial voltage for compensation is judged according to the dropping condition, so that the problem that the compensation of the energy storage device does not meet the standard is monitored and solved.
Further, when the system detects that the capacity expansion of the energy storage device is required, the energy storage device is accurately expanded through the difference between the first preset discharge voltage and the measured discharge voltage, and accurate guidance is provided for optimization and upgrading of the system.
Further, when the system performs voltage compensation, the voltage of the initial compensation is properly reduced during full power compensation of the energy storage device due to the time period of unstable voltage of the power supply end, but the voltage is reduced in the normal operation range of the load end, so that the time period of the voltage compensation is prolonged, and the safe and stable operation of the system is ensured.
Further, the central control module of the invention determines the reason causing the unstable voltage according to the power of the two ends by collecting the power supply power of the power supply end and the load power of the load end before the voltage compensation.
Furthermore, the invention divides the voltage compensation according to the occurrence position, thereby being convenient for the monitoring system to count and judge.
Further, the invention detects the frequency of unstable voltage of the power grid in the preset time period to determine whether the system operation accords with the preset standard, and when the frequency of unstable voltage is higher, secondary accurate judgment is further realized according to the duty ratio of each grade, so that weak points and fault occurrence conditions in the power system are accurately found.
Drawings
FIG. 1 is a schematic diagram of a power grid voltage intelligent monitoring system based on a dynamic voltage restorer according to an embodiment of the invention;
FIG. 2 is a flowchart of a method for determining whether the operation of the dynamic voltage restorer meets the preset standard according to the embodiment of the present invention;
FIG. 3 is a flowchart of a secondary determination of whether the operation of the dynamic voltage restorer meets the preset standard according to the embodiment of the present invention;
fig. 4 is a flow chart of a capacity expansion adjustment manner of the energy storage device according to an embodiment of the present invention.
Detailed Description
In order that the objects and advantages of the invention will become more apparent, the invention will be further described with reference to the following examples; it should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
It should be noted that, the data in this embodiment are obtained by comprehensive analysis and evaluation of the historical detection data of the central control module in the six months before the system is operated and the corresponding historical operation results. According to the invention, the central control module comprehensively determines the numerical value of each preset parameter standard aiming at the system operation before the operation according to the accumulated monitored voltage change in the first six months and 24420 times of voltage compensation parameters. It will be understood by those skilled in the art that the determination manner of the system according to the present invention for the parameters mentioned above may be that the value with the highest duty ratio is selected as the preset standard parameter according to the data distribution, the weighted summation is used to take the obtained value as the preset standard parameter, each history data is substituted into a specific formula, and the value obtained by using the formula is taken as the preset standard parameter or other selection manner, as long as different specific conditions in the single item determination process can be definitely defined by the obtained value by the system according to the present invention are satisfied.
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are merely for explaining the technical principles of the present invention, and are not intended to limit the scope of the present invention.
Referring to fig. 1 to fig. 4, schematic structural diagrams of a power grid voltage intelligent monitoring system based on a dynamic voltage restorer according to an embodiment of the invention are shown; the embodiment of the invention provides a flow chart of a judging mode of whether the operation of the dynamic voltage restorer accords with a preset standard or not; the embodiment of the invention discloses a flow chart for secondary judgment of whether the operation of a dynamic voltage restorer accords with a preset standard or not; the embodiment of the invention provides a flow chart of a capacity expansion adjusting mode of an energy storage device.
The embodiment of the invention provides a power grid voltage intelligent monitoring system based on a dynamic voltage restorer, which comprises the following components:
a power supply terminal including a power generation device for generating electric power and a transformer for adjusting a voltage of the electric power output from the power generation device;
the power supply grid is connected with the power supply end and used for conveying electric energy output by the power supply end;
the load end is connected with the power supply grid and comprises a plurality of electric equipment used for receiving and using the electric energy transmitted by the power supply grid;
the dynamic voltage restorer is arranged on the power supply network and is respectively connected with the power supply end and the load end through the power supply network, and comprises a switch for cutting off the power supply network when the power supply voltage is unstable, an energy storage device for supplying power to the load end after the power supply network is disconnected, and an inverter device arranged between the energy storage device and the load end for converting direct current output by the energy storage device into alternating current;
the detection module is respectively connected with the power supply end, the power supply grid, the load end and the dynamic voltage restorer and is used for detecting information of system operation; the information comprises the temperature of the energy storage device, the duration of voltage compensation, the capacity of the energy storage device, the discharge voltage of the energy storage device, the power supply power of the power supply end, the load power of the load end, the amplitude of voltage fluctuation and the frequency of voltage instability;
the central control module is connected with the detection module and is used for judging whether the operation of the dynamic voltage restorer accords with the standard according to the information detected by the detection module, determining whether the operation of the dynamic voltage restorer accords with the preset standard according to the discharge voltage of the energy storage device when the operation of the dynamic voltage restorer is primarily judged to be not in accordance with the standard, or determining the reason of unstable voltage of the power supply grid according to the difference value of the power supply power and the load power; the central control module generates a corresponding instruction according to the determined reason when the determination of the reason for the unstable voltage of the power supply grid is completed;
and the adjusting module is connected with the central control module, the power supply end and the dynamic voltage restorer and is used for adjusting the corresponding operation parameters in the system to the corresponding values according to the instructions output by the central control module.
Specifically, the central control module determines, according to the voltage compensation evaluation value E, whether the operation of the dynamic voltage restorer meets a determination mode of a preset standard under a first preset condition, and setsWherein，/>For the evaluation factor ∈ ->T is the highest temperature value of the energy storage device during single voltage compensation, T is the duration value of the single voltage compensation, n is the residual capacity of the energy storage device after the single voltage compensation, n epsilon (0, 1), wherein a first judgment mode is that the central control module judges that the operation of the dynamic voltage restorer meets a preset standard, and the power supply grid voltage is continuously compensated according to the current operation mode; the first determination mode satisfies that the voltage compensation evaluation value is smaller than a first preset voltage compensation evaluation value 375.00;
the second judging mode is that the central control module judges that the operation of the dynamic voltage restorer does not accord with a preset standard, and controls the detection module to detect the discharge voltage of the energy storage device, and the central control module determines whether the operation of the dynamic voltage restorer accords with a secondary judgment of the preset standard according to the detected discharge voltage of the energy storage device; the second determination means satisfies that the voltage compensation evaluation value is greater than or equal to the first preset voltage compensation evaluation value and less than a second preset voltage compensation evaluation value 512.00;
the third judging mode is that the central control module judges that the operation of the dynamic voltage restorer does not accord with a preset standard, and the central control module controls the detection module to detect the power supply power of the power supply end before voltage compensation and the load power of the load end before voltage compensation, and determines the judging mode for the reason of unstable voltage of the power supply network according to the difference value of the detected power supply power and the load power; the third judging mode meets the condition that the voltage compensation evaluation value is larger than or equal to the second preset voltage compensation evaluation value;
the first preset condition is that the dynamic voltage restorer completes single voltage compensation for a system.
Specifically, the central control module controls the detection module to detect the discharge voltage of the energy storage device in the second judging mode, and the central control module determines whether the operation of the dynamic voltage restorer meets the secondary judgment of a preset standard according to the detected discharge voltage, wherein,
the first secondary judgment is that the central control module judges that the operation of the dynamic voltage restorer does not accord with a preset standard, and expands the capacity of the energy storage device to a corresponding value according to the difference value between the first preset discharge voltage and the measured discharge voltage; the first secondary determination satisfies that the discharge voltage is less than the first preset discharge voltage 382V;
the second time is determined that the operation of the dynamic voltage restorer does not accord with a preset standard, and the initial compensation voltage in the voltage compensation process is reduced to a corresponding value according to the difference between the measured discharge voltage and the first preset discharge voltage; the second secondary judgment meets the condition that the discharge voltage is more than or equal to the first preset discharge voltage and less than 400V of a second preset discharge voltage;
the third secondary judgment is that the central control module judges that the operation of the dynamic voltage restorer meets a preset standard, and the power supply grid voltage is continuously compensated according to the current operation mode; the third secondary determination satisfies that the discharge voltage is equal to the second preset discharge voltage.
Specifically, the central control module calculates the difference between the first preset discharge voltage and the measured discharge voltage in the first secondary judgment mode, marks the difference as an expansion difference, and determines an adjustment mode for capacity expansion of the energy storage device according to the expansion difference,
the first capacity expansion adjustment mode is that the adjustment module expands the capacity of the energy storage device to a corresponding value by using a first preset capacity expansion coefficient 1.1; the first expansion adjustment mode satisfies that the expansion difference value is smaller than a first preset expansion difference value 12;
the second capacity expansion adjustment mode is that the adjustment module expands the capacity of the energy storage device to a corresponding value by using a second preset capacity expansion coefficient 1.2; the second expansion adjustment manner satisfies that the expansion difference value is greater than or equal to the first preset expansion difference value and less than a second preset expansion difference value 28;
the third capacity expansion adjustment mode is that the adjustment module expands the capacity of the energy storage device to a corresponding value by using a third preset capacity expansion coefficient of 1.4; the third expansion adjustment mode meets the condition that the expansion difference value is larger than or equal to the second preset expansion difference value.
Specifically, the central control module calculates the difference between the discharge voltage and the first preset discharge voltage in the second determination mode and marks the difference as a compensation difference, and the adjustment module determines an adjustment mode for the initial compensation voltage according to the compensation difference, wherein,
the first initial compensation voltage adjusting mode is that the adjusting module uses a first preset voltage adjusting coefficient of 0.99 to reduce the initial compensation voltage in the voltage compensation process to a corresponding value; the first initial compensation voltage adjusting mode meets the condition that the compensation difference value is smaller than a first preset compensation difference value;
the second initial compensation voltage adjusting mode is that the adjusting module uses a second preset voltage adjusting coefficient of 0.98 to reduce the initial compensation voltage in the voltage compensation process to a corresponding value; the second initial compensation voltage adjustment mode meets the condition that the compensation difference value is larger than or equal to the first preset compensation difference value and smaller than a second preset compensation difference value 6;
the third initial compensation voltage adjusting mode is that the adjusting module uses a third preset voltage adjusting coefficient of 0.96 to reduce the initial compensation voltage in the voltage compensation process to a corresponding value; the third initial compensation voltage adjustment mode satisfies that the compensation difference is greater than or equal to the second preset compensation difference 12.
Specifically, the central control module controls the detection module to detect the power supply of the power supply terminal before voltage compensation and the load power of the load terminal before voltage compensation under the third determination mode, and determines the determination mode for the reason of unstable voltage of the power supply network according to the difference value of the measured power supply and the load power,
the first type of judgment mode is that the central control module judges that the voltage of the power supply grid is unstable because the power consumption of the load end does not meet a preset standard, and the central control module counts rated power of electric equipment in the load end and limits the opening quantity of the electric equipment according to a counted result; the first type of judgment mode satisfies that the difference value between the power supply power and the load power is smaller than zero;
the second type of judgment mode is that the central control module judges that the reason that the voltage of the power supply grid is unstable is that the dynamic voltage restorer has hardware faults, and the central control module sends out a warning that the dynamic voltage restorer has hardware faults; the second type of judgment mode satisfies that the difference value between the power supply power and the load power is equal to zero;
the third type of judgment mode is a judgment mode that the central control module judges that the voltage instability of the power supply network is caused by that the power supply of the power supply end does not meet a preset standard, the central control module controls the detection module to detect the amplitude of voltage fluctuation, and whether the power supply of the power supply end meets the preset standard is determined according to the detected amplitude of the voltage fluctuation; the third type of judgment mode satisfies that the difference value between the power supply power and the load power is larger than zero.
Specifically, the central control module controls the amplitude of the voltage fluctuation measured by the detection module in the third type of judgment mode, and the central control module determines whether the power supply to the power supply terminal meets the judgment mode of the preset standard according to the measured amplitude of the voltage fluctuation,
the first power supply judging mode is that the central control module judges that the power supply of the power supply end meets a preset standard, and the power supply network is supplied with power according to the current power supply mode; the first power supply judging mode meets the condition that the amplitude of the voltage fluctuation is smaller than 10% of a preset fluctuation amplitude;
the second power supply judging mode is that the central control module judges that the power supply of the power supply end does not meet a preset standard, the central control module sends out a warning that the power of the transformer of the power supply end does not meet the preset standard and needs to be replaced, and the judging mode aiming at the power of the transformer to be replaced is determined according to the difference value between the amplitude of the voltage fluctuation and the preset fluctuation amplitude; the second power supply judging mode meets the condition that the amplitude of the voltage fluctuation is more than or equal to 10% of the preset fluctuation amplitude.
In particular, the central control module determines a determination mode for a voltage compensation event class according to the reason of the voltage instability of the power supply grid under a seventh preset condition, wherein,
the first level judgment mode is that the central control module judges that the voltage compensation event is a first level voltage compensation event; the first level judgment mode meets the reason that the voltage of the power supply grid is unstable because the power consumption of the load end does not meet the preset standard;
the second level judgment mode is that the central control module judges that the voltage compensation event is a second level voltage compensation event; the second level judgment mode meets the reason that the voltage of the power supply grid is unstable because the power supply end supplies power which does not meet the preset standard;
and the seventh preset condition is that the central control module completes the judgment of the reason of the unstable voltage of the power supply grid.
Specifically, the central control module controls the detection module to detect the frequency of occurrence of unstable voltage of the power supply network within the preset time length of 1h under the eighth preset condition, and the central control module determines a judging mode for whether the operation of the power supply network voltage intelligent monitoring system meets the preset standard according to the detected frequency,
the first operation judging mode is that the central control module judges that the operation of the intelligent power supply grid voltage monitoring system meets a preset standard, and monitors the power supply grid voltage according to the current operation mode; the first operation judgment mode meets the condition that the frequency is smaller than a preset frequency by 6 times;
the second operation judging mode is a secondary judging mode that the central control module judges that the operation of the power supply grid voltage intelligent monitoring system does not accord with a preset standard, the central control module further counts voltage compensation event grades, and determines whether the operation of the power supply grid voltage intelligent monitoring system accords with the preset standard according to the duty ratio of each grade; the second operation judgment mode meets the condition that the frequency is greater than or equal to a preset frequency;
and the eighth preset condition is that the central control module completes the judgment of the voltage compensation event level.
Specifically, the central control module determines, according to the duty ratio of each stage of voltage compensation event, a secondary determination as to whether the operation of the power supply grid voltage intelligent monitoring system meets a preset standard in the second operation determination mode, wherein,
the first type of operation is determined that the central control module determines that the operation of the power supply grid voltage intelligent monitoring system does not accord with a preset standard, and the output voltage of the power supply end is increased to a corresponding value according to the difference value between the duty ratio of a primary voltage compensation event and the preset duty ratio; the first type of operation judges that the duty ratio of the first-stage voltage compensation event is larger than a preset duty ratio of 55%;
the second type of operation is determined that the central control module determines that the operation of the power supply grid voltage intelligent monitoring system does not meet a preset standard, and the power supply end electric energy capacity is expanded to a corresponding value according to the difference between the duty ratio of the secondary voltage compensation event and the preset duty ratio; and the second type of operation judges that the duty ratio of the secondary voltage compensation event is larger than a preset duty ratio.
Example 1
Taking the primary voltage instability monitored by the system as an example:
XX is divided into XX seconds in XX month XX and XX day XX, the rated voltage of a power supply grid is reduced from 400V to 328V, the time duration of the reduction is 880ms, the system starts a dynamic voltage restorer to conduct voltage compensation, a detection module in the system further detects that the highest temperature of an energy storage device is 48 ℃, the compensation time is 880ms, and the residual capacity of the energy storage device after compensation is 0.76.
And the central control module obtains a voltage compensation evaluation value E= 58.05, and if the obtained voltage compensation evaluation value is smaller than a first preset voltage compensation evaluation value 125.00, the operation of the dynamic voltage restorer is judged to accord with a preset standard, and the voltage of the power supply grid is continuously compensated according to the current operation mode.
Example 2
Taking another voltage instability monitored by the system as an example:
XX is divided into XX seconds in XXXX month XX day XX, and the rated voltage of a power supply grid is reduced from 400V to 285V, the time length of the sag is 2700ms, the system starts a dynamic voltage restorer to conduct voltage compensation, a detection module in the system further detects that the highest temperature of an energy storage device is 66 ℃, the compensation time is 2700ms, and the residual capacity of the energy storage device after compensation is 0.42.
The central control module obtains a voltage compensation evaluation value E= 683.91, the obtained voltage compensation evaluation value is between a first preset voltage compensation evaluation value 125.00 and a second preset voltage compensation evaluation value 712.00, the central control module judges that the operation of the dynamic voltage restorer does not meet a preset standard, the calling detection module detects that the discharge voltage of the energy storage device in voltage compensation is reduced from an initial 400V to 372V, the central control module judges that the operation of the dynamic voltage restorer does not meet the preset standard, and the capacity of the energy storage device is expanded to a corresponding value 2200KVA by using a first preset expansion coefficient 1.1.
Example 3
Taking the example of voltage instability within a certain period of time monitored by the system:
monitoring of the voltage during 13 hours 30 minutes 00 seconds to 14 hours 30 minutes 00 seconds of XX year XX month XX day, information of voltage instability during this period is shown in table 1:
table 1 monitoring table for information of voltage instability
Screening out data with the voltage compensation evaluation value greater than or equal to the second preset voltage compensation evaluation value 512.00 from the time period, further judging the reason of the data and judging the voltage compensation event grade, wherein the screening and counting results are shown in table 2:
TABLE 2 Voltage instability information analysis Table
The frequency of occurrence of voltage instability in 1h is 12 times and is greater than the preset frequency by 6 times, the duty ratio of each stage of voltage compensation event is further counted to obtain a first stage of voltage compensation event 2 times, the duty ratio of each second stage of voltage compensation event is 7 times and is respectively 16% and 58%, and the power capacity of the power supply end is extended by 3% according to the difference of 3% between the duty ratio of each second stage of voltage compensation event 58% and the preset duty ratio of 55%.
Thus far, the technical solution of the present invention has been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of protection of the present invention is not limited to these specific embodiments. Equivalent modifications and substitutions for related technical features may be made by those skilled in the art without departing from the principles of the present invention, and such modifications and substitutions will be within the scope of the present invention.
The foregoing description is only of the preferred embodiments of the invention and is not intended to limit the invention; various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A power grid voltage intelligent monitoring system based on a dynamic voltage restorer is characterized by comprising:
a power supply terminal including a power generation device for generating electric power and a transformer for adjusting a voltage of the electric power output from the power generation device;
the power supply grid is connected with the power supply end and used for conveying electric energy output by the power supply end;
the load end is connected with the power supply grid and comprises a plurality of electric equipment used for receiving and using the electric energy transmitted by the power supply grid;
the dynamic voltage restorer is arranged on the power supply network and is respectively connected with the power supply end and the load end through the power supply network, and comprises a switch for cutting off the power supply network when the power supply voltage is unstable, an energy storage device for supplying power to the load end after the power supply network is disconnected, and an inverter device arranged between the energy storage device and the load end for converting direct current output by the energy storage device into alternating current;
the detection module is respectively connected with the power supply end, the power supply grid, the load end and the dynamic voltage restorer and is used for detecting information of system operation;
the central control module is connected with the detection module and is used for judging whether the operation of the dynamic voltage restorer accords with the standard according to the information detected by the detection module, determining whether the operation of the dynamic voltage restorer accords with the preset standard according to the discharge voltage of the energy storage device when the operation of the dynamic voltage restorer is primarily judged to be not in accordance with the standard, or determining the reason of unstable voltage of the power supply grid according to the difference value of the power supply power and the load power; the central control module generates a corresponding instruction according to the determined reason when the determination of the reason for the unstable voltage of the power supply grid is completed;
the adjusting module is connected with the central control module, the power supply end and the dynamic voltage restorer and is used for adjusting corresponding operation parameters in the system to corresponding values according to the instruction output by the central control module;
the central control module determines a judging mode aiming at whether the operation of the dynamic voltage restorer accords with a preset standard or not according to the voltage compensation evaluation value E under a first preset condition, and setsWherein->For the evaluation factor ∈ ->T is the highest temperature value of the energy storage device during single voltage compensation, T is the duration value of the single voltage compensation, n is the residual capacity of the energy storage device after the single voltage compensation, n epsilon (0, 1),the central control module judges that the operation of the dynamic voltage restorer does not accord with a preset standard when the voltage compensation evaluation value E is larger than or equal to a first preset voltage compensation evaluation value, and judges whether the operation of the dynamic voltage restorer accords with the preset standard according to the measured discharge voltage of the energy storage device when the voltage compensation evaluation value E is smaller than a second preset voltage compensation evaluation value, or determines the reason of the instability of the voltage of the power supply grid according to the difference value between the power supply power of the power supply end before voltage compensation and the load power of the load end before voltage compensation, which is measured by the detection module, when the voltage compensation evaluation value E is larger than or equal to the second preset voltage compensation evaluation value;
the first preset condition is that the dynamic voltage restorer completes single voltage compensation for a system;
the central control module performs secondary judgment on whether the operation of the dynamic voltage restorer accords with a preset standard according to the discharge voltage measured by the detection module under a second preset condition, and controls the adjustment module to expand the capacity of the energy storage device to a corresponding value according to the difference value between a first preset discharge voltage and the measured discharge voltage when the operation of the dynamic voltage restorer is judged to be not in accordance with the standard, or controls the adjustment module to reduce the initial compensation voltage in the voltage compensation process to the corresponding value according to the difference value between the measured discharge voltage and the first preset discharge voltage;
the central control module controls the regulating module to expand the capacity of the energy storage device when the discharge voltage is smaller than the first preset discharge voltage, or controls the regulating module to reduce the initial compensation voltage value when the discharge voltage is larger than or equal to the first preset discharge voltage and smaller than a second preset discharge voltage;
and the second preset condition is that the central control module carries out secondary judgment on whether the operation of the dynamic voltage restorer accords with a preset standard.
2. The intelligent power grid voltage monitoring system based on the dynamic voltage restorer according to claim 1, wherein the central control module is provided with a plurality of capacity expansion adjustment modes aiming at the capacity of the energy storage device under a third preset condition, and the capacities of the energy storage devices adjusted by the adjustment modes are different;
the third preset condition is that the central control module controls the adjusting module to expand the capacity of the energy storage device to a corresponding value according to the difference value between the first preset discharge voltage and the measured discharge voltage.
3. The intelligent power grid voltage monitoring system based on the dynamic voltage restorer according to claim 2, wherein the central control module is provided with a plurality of voltage regulation modes aiming at initial compensation voltage in the voltage compensation process under a fourth preset condition, and the initial compensation voltages regulated by the regulation modes are different;
the fourth preset condition is that the central control module controls the adjusting module to reduce the initial compensation voltage in the voltage compensation process to a corresponding value according to the difference value between the measured discharge voltage and the first preset discharge voltage.
4. The intelligent power grid voltage monitoring system based on the dynamic voltage restorer according to claim 3, wherein the central control module selects a corresponding processing mode according to the determined cause of the unstable voltage of the power supply grid under a fifth preset condition, and the intelligent power grid voltage monitoring system comprises:
when the voltage of the power supply network is unstable because the power consumption of the load end does not meet the preset standard, the rated power of the electric equipment in the load end is counted, the opening quantity of the electric equipment is limited according to the counted result,
when the voltage instability of the power supply grid is judged because the dynamic voltage restorer has hardware faults, the warning that the dynamic voltage restorer has hardware faults is sent out,
when the reason that the voltage of the power supply network is unstable is that the power supply of the power supply end does not meet the preset standard is judged, the central control module controls the detection module to detect the amplitude of the voltage fluctuation, and whether the power supply of the power supply end meets the preset standard is determined according to the detected amplitude of the voltage fluctuation;
the central control module judges that the power consumption of the load end does not meet a preset standard when the difference value of the power supply and the load power is smaller than zero, judges that the dynamic voltage restorer has hardware faults when the difference value of the power supply and the load power is equal to zero, and judges that the power supply of the power supply end does not meet the preset standard when the difference value of the power supply and the load power is larger than zero;
the fifth preset condition is that the central control module determines the reason for unstable voltage of the power supply grid according to the difference value of the power supply power and the load power.
5. The intelligent power grid voltage monitoring system based on the dynamic voltage restorer according to claim 4, wherein the central control module controls the detection module to detect the amplitude of voltage fluctuation under a sixth preset condition, and when the power supply of the power supply end is determined to be not in accordance with a preset standard according to the detected amplitude of voltage fluctuation, the central control module sends out a warning that the power of the transformer of the power supply end is not in accordance with the preset standard and needs to be replaced, and determines the power of the transformer to be replaced according to the difference value between the amplitude of voltage fluctuation and the preset fluctuation amplitude;
the sixth preset condition is that the reason that the voltage of the power supply grid determined by the central control module is unstable is that the power supply end does not meet a preset standard.
6. The dynamic voltage restorer-based grid voltage intelligent monitoring system of claim 5, wherein the central control module determines a decision for a voltage compensation event class according to a determined cause of voltage instability of the power supply grid under a seventh preset condition, comprising:
when the voltage of the power supply grid is unstable because the power consumption of the load end does not meet the preset standard, the voltage compensation event is judged to be a primary voltage compensation event,
when the voltage of the power supply network is unstable because the power supply end supplies power which does not meet the preset standard, judging that the voltage compensation event is a secondary voltage compensation event;
and the seventh preset condition is that the central control module completes the judgment of the reason of the unstable voltage of the power supply grid.
7. The intelligent power grid voltage monitoring system based on the dynamic voltage restorer according to claim 6, wherein the central control module controls the detection module to detect the frequency of occurrence of voltage instability of the power supply grid within a preset time period under an eighth preset condition, judges whether the operation of the intelligent power supply grid voltage monitoring system does not meet a preset standard according to the detected frequency, counts voltage compensation event levels, and judges whether the operation of the intelligent power supply grid voltage monitoring system meets the preset standard or not according to the duty ratio of each level;
and the eighth preset condition is that the central control module completes the judgment of the voltage compensation event level.
8. The intelligent power grid voltage monitoring system based on the dynamic voltage restorer according to claim 7, wherein the central control module determines whether the operation of the intelligent power grid voltage monitoring system meets a secondary judgment of a preset standard according to the duty ratio of each level of voltage compensation event under a ninth preset condition, and increases the output voltage of the power supply end to a corresponding value according to the difference between the duty ratio of the primary voltage compensation event and the preset duty ratio when the operation of the intelligent power grid voltage monitoring system does not meet the preset standard, or increases the power energy capacity of the power supply end to a corresponding value according to the difference between the duty ratio of the secondary voltage compensation event and the preset duty ratio;
the central control module increases the output voltage of the power supply end to a corresponding value when the duty ratio of the primary voltage compensation event is larger than a preset duty ratio, and expands the power energy capacity of the power supply end to a corresponding value when the duty ratio of the secondary voltage compensation event is larger than the preset duty ratio;
and the ninth preset condition is that the central control module performs secondary judgment on whether the operation of the intelligent power supply grid voltage monitoring system meets a preset standard or not.
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| CN201156669Y (en) * | 2008-01-08 | 2008-11-26 | 江苏省电力试验研究院有限公司 | Series capacity direct coupling type dynamic voltage recovery device |
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| TWI510877B (en) * | 2013-10-23 | 2015-12-01 | Ind Tech Res Inst | Voltage compensation circuit and control method thereof |
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| CN201156669Y (en) * | 2008-01-08 | 2008-11-26 | 江苏省电力试验研究院有限公司 | Series capacity direct coupling type dynamic voltage recovery device |
| CN203481839U (en) * | 2013-09-17 | 2014-03-12 | 无锡力豪科技有限公司 | Super capacitor dynamic voltage recovery system and power supply system |
| CN104052062A (en) * | 2014-06-10 | 2014-09-17 | 江苏大学 | Dynamic voltage restorer compensation control method based on minimum active power injection |
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