Power control method of self-contained power grid based on electronic load

Abstract

The present invention relates to the technical field of power system safety and stability control, and provides a self-contained power grid power control method based on electronic load, including: when the power system trips due to a fault, analyzing the tripping cause, and putting in or removing the electronic load according to the tripping cause; judging whether the deviation between the put-in or removed electronic load power and the tripping power is within the grid bearing range, if so, putting in or removing the electronic load until the system moves stably; if not, optimally cutting the unit power or the optimal load cutting power in the entire grid structure. According to the scheme of the present invention, the granularity of weak power grid units can be refined, over-cutting or under-cutting errors can be reduced, and the low-frequency load reduction of the third line of defense can be prevented from continuing to operate after the safety and stability strategy is activated, forming a "seesaw" and causing a power outage in the entire grid; at the same time, the unit is not preferentially removed after the accident occurs, so as to ensure the operation of the power grid and the economic benefits of users, and improve the speed of power grid recovery after the accident, which has economic significance and practical value for the self-contained power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of power system safety and stability control, and in particular to a self-contained power grid power control method based on electronic load. Background Art

[0002] With the development of the national economy and the reform of the power system, at this stage, some enterprises in my country have developed self-owned power grids that integrate "generation, transmission, distribution, and sales". The independently operated self-owned power grids show the characteristics of "large units, large loads, and small power grids". In order to pursue economic benefits, the units and loads of the enterprise's self-owned power grid are all fully loaded. When the unit (load) trips, the system needs to cut off the load (unit) in order to maintain frequency stability. Due to the large output of the unit during normal operation (large load proportion), the granularity of cutting is too large, and the system power balance cannot be guaranteed, and it is difficult to maintain the stability of the grid. In severe cases, a "seesaw" event will occur, in which the unit (load) is cut and then the load (unit) is cut back, and the entire network is eventually blacked out.

[0003] At the same time, in a system with large units, large loads and small power grid, after the units (loads) are removed, it is difficult to restore the units (loads) that account for a large proportion of the system. Summary of the invention

[0004] The purpose of the present invention is to solve at least one technical problem in the background technology and provide a self-contained power grid power control method based on electronic load.

[0005] To achieve the above object, the present invention provides a self-contained power grid power control method based on electronic load, comprising:

[0006] When the power system trips due to a fault, analyze the cause of the trip and switch the electronic load on or off according to the cause of the trip;

[0007] Determine whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid tolerance range. If so, put the electronic load into or cut off until the system moves stably; if not, optimally cut the unit power or optimally cut the load power in the entire grid structure.

[0008] According to one aspect of the present invention, when the power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including:

[0009] When a power system load fails and trips, the electronic load is put into use according to the load power before tripping to consume the excess power of the system units.

[0010] According to one aspect of the present invention, the step of judging whether the deviation between the electronic load power to be put into operation or removed and the tripping power is within the tolerance range of the grid, and if so, putting into operation or removing the electronic load until the system moves stably; if not, optimally cutting the unit power or the optimal load cutting power in the entire grid structure includes:

[0011] When the deviation between the total power of the electronic load put into operation and the tripping load power is within the grid tolerance range, the system will operate stably after n electronic loads are put into operation; otherwise, the power of the units will be optimally cut in the entire grid structure.

[0012] According to one aspect of the present invention, the optimal power cutting of the generator set in the entire grid structure includes:

[0013] When the optimal power cut-off is over-cut, the system frequency decreases, and the electronic load is exited to reduce power consumption. The exit quantity n = (Pg-Pl) / Pd, where Pg is the power of the cut-off unit, P1 is the power before the power system load trips, and Pd is the rated power of the electronic load.

[0014] According to one aspect of the present invention, the optimal power cutting of the generator set in the entire grid structure includes:

[0015] When the optimal cutting unit power is under-cut, the system frequency increases, and the electronic load is put into use to consume power. The input quantity n = (Pl-Pg) / Pd, where Pg is the cutting unit power, P1 is the power before the power system load trips, and Pd is the rated power of the electronic load.

[0016] According to one aspect of the present invention, when the power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including:

[0017] When a power system unit fails and trips, the electronic load is cut off according to the unit power before tripping.

[0018] According to one aspect of the present invention, the step of judging whether the deviation between the electronic load power to be put into operation or removed and the tripping power is within the tolerance range of the grid, and if so, putting into operation or removing the electronic load until the system moves stably; if not, optimally cutting the unit power or the optimal load cutting power in the entire grid structure includes:

[0019] When the deviation between the total power of the removed electronic loads and the power of the tripped unit is within the grid tolerance range, the system will operate stably after n electronic loads are removed; otherwise, the optimal load removal power is achieved in the entire grid structure.

[0020] According to one aspect of the present invention, the optimal load shedding power in the entire grid structure includes:

[0021] When the optimal load shedding power is over-cut, the system frequency increases, and the electronic load is put into operation to balance the over-cut load. The input quantity n = (Pl-Pg) / Pd, where Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load.

[0022] According to one aspect of the present invention, the optimal load shedding power in the entire grid structure includes:

[0023] When the optimal load shedding power is under-cut, the system frequency decreases, and the electronic load is cut to balance the under-cut load. The cut-off quantity n = (Pg-Pl) / Pd, where Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load.

[0024] According to one aspect of the present invention, the number of electronic loads put into operation is set according to the single maximum unit power Pgm of the self-contained power grid and the single maximum load power Plm of the power system, n1=Pgm / Pd, n2=Plm / Pd, wherein n1 and n2 are the numbers of electronic loads put into operation respectively, and Pd is the rated power of the electronic load.

[0025] According to the scheme of the present invention, the self-contained power grid power control method based on electronic load proposed in the present invention can refine the granularity of weak power grid units (loads), reduce over-cutting or under-cutting errors, and prevent the third line of defense low-frequency load reduction (high-frequency machine cutting) from continuing to operate after the safety and stability strategy is activated, forming a "seesaw" and causing power outages in the entire network; at the same time, after an accident occurs, the unit (load) is not removed first, ensuring the operation of the power grid and the economic benefits of users, and improving the speed of power grid recovery after the accident, which has very significant economic significance and practical value for the self-contained power grid.

[0026] According to the solution of the present invention, when a system failure occurs, the electronic load regulation function can be used to enable the system to reach a new power balance point, thereby achieving the purpose of not cutting off the unit (load), which has very significant economic significance and practical value for the stability and rapid recovery of the self-contained power grid.

[0027] According to the solution of the present invention, the present invention utilizes electronic loads to adjust the power balance of weak power grids, refines the power regulation granularity, increases the anti-interference capability of weak self-provided power grids, solves the problem of power outages in the entire grid caused by weak self-provided power grids, and at the same time reduces the number of units (loads) removed during an accident, simplifying the process of restoring normal operation of the power grid after an accident. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A flowchart schematically showing a method for controlling power of a self-contained power grid based on an electronic load according to an embodiment of the present invention;

[0029] Figure 2A schematic diagram showing a grid arrangement according to an embodiment of the present invention;

[0030] Figure 3 The block diagram schematically shows the structural arrangement of a self-contained power grid power control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The content of the present invention will now be discussed with reference to exemplary embodiments. It should be understood that the embodiments discussed are only to enable those skilled in the art to better understand and thus implement the content of the present invention, rather than implying any limitation on the scope of the present invention.

[0032] As used herein, the term “including” and variations thereof are to be interpreted as open-ended terms meaning “including, but not limited to.” The term “based on” is to be interpreted as “based, at least in part, on.” The terms “one embodiment” and “an embodiment” are to be interpreted as “at least one embodiment.”

[0033] Figure 1 The flowchart schematically shows a self-contained power grid power control method based on electronic load according to an embodiment of the present invention. Figure 1 As shown, in this embodiment, the self-provided power grid power control method based on electronic load includes:

[0034] When the power system trips due to a fault, analyze the cause of the trip and switch the electronic load on or off according to the cause of the trip;

[0035] Determine whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid tolerance range. If so, put the electronic load into or cut off until the system moves stably; if not, optimally cut the unit power or optimally cut the load power in the entire grid structure.

[0036] Figure 2 Schematically shows a grid layout diagram according to an embodiment of the present invention. Figure 2 As shown, in the present invention, a resistive electronic load is installed on the self-provided power grid side, and when the electronic load is put into operation, the power consumption is Pd.

[0037] According to an embodiment of the present invention, when a power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including:

[0038] When the power system load fails and trips, the electronic load is put into use according to the load power before tripping to consume the excess power of the system units without cutting off the units. The number of electronic loads put into use is n.

[0039] In this embodiment, it is determined whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid tolerance range. If so, the electronic load is put into or cut off until the system moves stably; if not, the optimal unit power or optimal load shedding power is cut off in the entire grid structure, including:

[0040] When the deviation between the total power of the electronic load put into operation and the tripping load power is within the grid tolerance range, the system will operate stably after n electronic loads are put into operation; otherwise, the power of the units will be optimally cut in the entire grid structure.

[0041] In this embodiment, the optimal power cutting of the generator set in the entire grid structure includes:

[0042] When the optimal power of the cutting unit is over-cut, the system frequency is reduced, and the electronic load is withdrawn to reduce power consumption. The withdrawal quantity n = (Pg-Pl) / Pd, to prevent the system from under-frequency and reverse load cutting after over-cutting the unit;

[0043] Among them, Pg is the power of the cut-off unit, P1 is the power of the power system load before tripping, and Pd is the rated power of the electronic load.

[0044] In this embodiment, the optimal power cutting of the generator set in the entire grid structure includes:

[0045] When the optimal power of the cutting unit is under-cut, the system frequency increases, and the electronic load is put into use to consume power. The number of inputs is n = (Pl-Pg) / Pd, to prevent the system from cutting off other large units at high frequency after the under-cut unit;

[0046] Among them, Pg is the power of the cut-off unit, P1 is the power of the power system load before tripping, and Pd is the rated power of the electronic load.

[0047] According to another embodiment of the present invention, when a power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including:

[0048] When a power system unit fails and trips, the electronic load is cut off according to the unit power before tripping.

[0049] In this embodiment, it is determined whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid tolerance range. If so, the electronic load is put into or cut off until the system moves stably; if not, the optimal unit power or optimal load shedding power is cut off in the entire grid structure, including:

[0050] When the deviation between the total power of the removed electronic loads and the power of the tripped unit is within the grid tolerance range, the system will operate stably after n electronic loads are removed; otherwise, the optimal load removal power is achieved in the entire grid structure.

[0051] In this embodiment, the optimal load shedding power in the entire grid structure includes:

[0052] When the optimal load shedding power is over-shedding, the system frequency increases. The electronic load is put into operation to balance the over-shed load quantity, and the input quantity n = (Pl - Pg) / Pd, preventing the system from having high frequency and then reclosing the unit after over-shedding the load.

[0053] Wherein, Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load.

[0054] In this embodiment, the optimal load shedding power in the entire grid structure includes:

[0055] When the optimal load shedding power is under-shedding, the system frequency decreases. The electronic load is cut to balance the under-shed load quantity, and the cut quantity n = (Pg - Pl) / Pd, preventing the low-frequency load shedding action of the system after under-shedding the load.

[0056] Wherein, Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load.

[0057] Preferably, the rated power Pd of the power system is selected according to the bearing range Pset of the self-provided power grid. Usually, Pset < Pd < 2*Pset can be selected to ensure that the system granularity meets the stability requirements.

[0058] Preferably, the quantity of the input electronic load is set according to the maximum power Pgm of a single unit in the self-provided power grid and the maximum load power Plm of a single body in the power system. n1 = Pgm / Pd, n2 = Plm / Pd, where n1 and n2 are respectively the quantity of the input electronic load, and Pd is the rated power of the electronic load. Take the maximum value of n1 and n2 to ensure that the unit (load) is not cut off when the system fails.

[0059] According to the above solution of the present invention, the power control method of the self-provided power grid based on the electronic load can refine the granularity of the units (loads) in the weak grid, reduce the over-shedding or under-shedding error, prevent the third line of defense, i.e., the low-frequency load shedding (high-frequency generator tripping), from continuing to act after the safety and stability strategy acts, forming a "seesaw" resulting in a blackout of the entire network; at the same time, the unit (load) is not preferentially cut off after the accident, ensuring the operation of the power grid and the economic benefits of users, improving the power grid restoration speed after the accident, and having very significant economic significance and practical value for the self-provided power grid.

[0060] According to the above solution of the present invention, when a system failure occurs, the electronic load regulation function can be utilized to make the system reach a new power balance point, achieving the purpose of not cutting off the unit (load), and having very significant economic significance and practical value for the stability and rapid restoration of the self-provided power grid.

[0061] According to the above scheme of the present invention, the present invention utilizes electronic loads to adjust the power balance of weak power grids, refine the power regulation granularity, increase the anti-interference ability of weak self-provided power grids, solve the problem of power outages in the entire network caused by weak self-provided power grids, and at the same time reduce the number of units (loads) cut off during accidents, simplifying the process of restoring normal operation of the power grid after accidents.

[0062] Based on the above solution of the present invention, the present invention also provides a self-contained power grid power control system, and its structural arrangement block diagram is as follows: Figure 3 As shown, including:

[0063] Unit control device, load control device, communication interface device;

[0064] Among them, the unit control device collects the unit voltage, current and power, and can cut off the unit according to the control strategy.

[0065] The load control device collects load voltage, current and power, and can remove the load according to the control strategy.

[0066] The unit control device and the load control device are connected via a communication interface device to achieve full network power control.

[0067] The self-contained power grid power control system according to the present invention can implement the self-contained power grid power control method described above, specifically:

[0068] When the power system trips due to a fault, the cause of the trip is analyzed, and the load control device switches on or off the electronic load according to the cause of the trip;

[0069] Determine whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid bearing range. If so, the load control device puts the electronic load into or cuts off until the system moves stably; if not, the unit control device or the load control device optimally cuts the unit power or the optimal load power in the entire grid structure.

[0070] According to an embodiment of the present invention, when a power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including:

[0071] When the power system load fails and trips, the electronic load is put into use according to the load power before tripping to consume the excess power of the system units without cutting off the units. The number of electronic loads put into use is n.

[0072] In this embodiment, it is determined whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid tolerance range. If so, the electronic load is put into or cut off until the system moves stably; if not, the optimal unit power or optimal load shedding power is cut off in the entire grid structure, including:

[0073] When the deviation between the total power of the electronic load put into operation and the tripping load power is within the grid tolerance range, the system will operate stably after n electronic loads are put into operation; otherwise, the power of the units will be optimally cut in the entire grid structure.

[0074] In this embodiment, the optimal power cutting of the generator set in the entire grid structure includes:

[0075] When the optimal power of the cutting unit is over-cut, the system frequency is reduced, and the electronic load is withdrawn to reduce power consumption. The withdrawal quantity n = (Pg-Pl) / Pd, to prevent the system from under-frequency and reverse load cutting after over-cutting the unit;

[0076] Among them, Pg is the power of the cut-off unit, P1 is the power of the power system load before tripping, and Pd is the rated power of the electronic load.

[0077] In this embodiment, the optimal power cutting of the generator set in the entire grid structure includes:

[0078] When the optimal power of the cutting unit is under-cut, the system frequency increases, and the electronic load is put into use to consume power. The number of inputs is n = (Pl-Pg) / Pd, to prevent the system from cutting off other large units at high frequency after the under-cut unit;

[0079] Among them, Pg is the power of the cut-off unit, P1 is the power of the power system load before tripping, and Pd is the rated power of the electronic load.

[0080] According to another embodiment of the present invention, when a power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including:

[0081] When a power system unit fails and trips, the electronic load is cut off according to the unit power before tripping.

[0082] In this embodiment, it is determined whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid tolerance range. If so, the electronic load is put into or cut off until the system moves stably; if not, the optimal unit power or optimal load shedding power is cut off in the entire grid structure, including:

[0083] When the deviation between the total power of the removed electronic loads and the power of the tripped unit is within the grid tolerance range, the system will operate stably after n electronic loads are removed; otherwise, the optimal load removal power is achieved in the entire grid structure.

[0084] In this embodiment, the optimal load shedding power in the entire grid structure includes:

[0085] When the optimal load shedding power is over-shedding, the system frequency increases. The electronic load is put into operation to balance the over-shed load quantity, and the input quantity n = (Pl - Pg) / Pd, preventing the system from having high frequency and then reclosing the unit after over-shedding the load;

[0086] Among them, Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load.

[0087] In this embodiment, the optimal load shedding power in the entire grid structure includes:

[0088] When the optimal load shedding power is under-shedding, the system frequency decreases. Supplementary cutting of the electronic load is carried out to balance the under-shed load quantity, and the cutting quantity n = (Pg - Pl) / Pd, preventing the under-frequency load shedding operation of the system after under-shedding the load;

[0089] Among them, Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load.

[0090] Preferably, the rated power Pd of the power system is selected according to the bearing range Pset of the self-provided power grid. Usually, Pset < Pd < 2*Pset can be selected to ensure that the system granularity meets the stability requirements.

[0091] Preferably, the quantity of the input electronic load is set according to the maximum power Pgm of a single unit in the self-provided power grid and the maximum load power Plm of a single body in the power system. n1 = Pgm / Pd, n2 = Plm / Pd, where n1 and n2 are respectively the quantity of the input electronic load, and Pd is the rated power of the power system. Take the maximum value of n1 and n2 to ensure that the unit (load) is not cut off when the system fails.

[0092] According to the self-provided power grid power control system of the present invention, it can refine the granularity of the units (loads) in the weak power grid, reduce the over-shedding or under-shedding error, prevent the third line of defense, i.e., under-frequency load shedding (high-frequency generator tripping), from continuing to operate after the safety and stability strategy acts, and form a "seesaw" resulting in a blackout of the entire network; at the same time, it does not preferentially cut off the unit (load) after an accident, ensuring the operation of the power grid and the economic benefits of users, improving the power grid restoration speed after an accident, and having very significant economic significance and practical value for the self-provided power grid.

[0093] When a system fault occurs, the electronic load regulation function can be utilized to make the system reach a new power balance point, achieving the purpose of not cutting off the unit (load), and having very significant economic significance and practical value for the stability and rapid restoration of the self-provided power grid.

[0094] Electronic loads are used to adjust the power balance of weak power grids, refine the granularity of power regulation, increase the anti-interference ability of weak self-provided power grids, and solve the problem of power outages in the entire network caused by weak self-provided power grids. At the same time, the number of units (loads) removed during accidents is reduced, simplifying the process of restoring normal operation of the power grid after an accident.

[0095] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A self-contained power grid power control method based on electronic load, characterized in that: include: When the power system trips due to a fault, analyze the cause of the trip and switch the electronic load on or off according to the cause of the trip; Determine whether the deviation between the electronic load power put into or cut off and the tripping power is within the grid tolerance range. If so, put into or cut off the electronic load until the system moves stably; if not, cut the unit power or load power optimally in the entire grid structure; The optimal power cut of the generator set includes: When the optimal power cut-off is over-cut, the system frequency is reduced, and the electronic load is exited to reduce power consumption. The exit quantity n=(Pg-Pl) / Pd, where Pg is the power of the cut-off unit, P1 is the power before the power system load trips, and Pd is the rated power of the electronic load; When the optimal power of the cut-off unit is under-cut, the system frequency increases, and the electronic load is put into use to consume power. The number of inputs is n=(Pl-Pg) / Pd, where Pg is the power of the cut-off unit, P1 is the power before the power system load trips, and Pd is the rated power of the electronic load; The number of electronic loads put into operation is set according to the maximum power of a single unit Pgm of the self-provided power grid and the maximum load power Plm of the power system, n1=Pgm / Pd, n2=Plm / Pd, where n1 and n2 are the number of electronic loads put into operation, respectively, and Pd is the rated power of the electronic load; The step of judging whether the deviation between the electronic load power to be put into operation or removed and the tripping power is within the tolerance range of the grid, and if so, putting into operation or removing the electronic load until the system moves stably; if not, optimally cutting the unit power or the optimal load cutting power in the entire grid structure includes: When the deviation between the total power of the removed electronic loads and the power of the tripped unit is within the grid tolerance range, the system will operate stably after removing n electronic loads; otherwise, the optimal load removal power is achieved in the entire grid structure; The optimal load shedding power in the entire grid structure includes: When the optimal load shedding power is over-cut, the system frequency increases, and the electronic load is put into operation to balance the over-cut load. The input quantity n=(Pl-Pg) / Pd, where Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load. The optimal load shedding power in the entire grid structure includes: When the optimal load shedding power is under-cut, the system frequency decreases, and the electronic load is cut to balance the under-cut load. The cut-off quantity n=(Pg-Pl) / Pd, where Pg is the power before the unit trips, P1 is the optimal load shedding power of the power system, and Pd is the rated power of the electronic load.

2. The self-contained power grid power control method based on electronic load according to claim 1, characterized in that: When the power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including: When a power system load fails and trips, the electronic load is put into use according to the load power before tripping to consume the excess power of the system units.

3. The self-contained power grid power control method based on electronic load according to claim 2, characterized in that: The step of judging whether the deviation between the power of the electronic load put into operation or removed and the tripping power is within the tolerance range of the grid, and if so, putting into operation or removing the electronic load until the system moves stably; If not, then the optimal shedding power of the unit or the optimal shedding power of the load in the entire grid structure includes: When the deviation between the total power of the electronic load put into operation and the trip load power is within the grid tolerance range, the system will operate stably after n electronic loads are put into operation; Otherwise, the power of the generator set is optimally cut in the entire grid structure.

4. The self-contained power grid power control method based on electronic load according to claim 1, characterized in that: When the power system trips due to a fault, the cause of the trip is analyzed, and the electronic load is switched on or off according to the cause of the trip, including: When a power system unit fails and trips, the electronic load is cut off according to the unit power before tripping.

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