CN104300558A - Calculating method and system for active power shortage of micro-grid - Google Patents

Calculating method and system for active power shortage of micro-grid Download PDF

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CN104300558A
CN104300558A CN201410601609.4A CN201410601609A CN104300558A CN 104300558 A CN104300558 A CN 104300558A CN 201410601609 A CN201410601609 A CN 201410601609A CN 104300558 A CN104300558 A CN 104300558A
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mrow
msub
active power
msup
frequency
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CN104300558B (en
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彭世康
王伟
马红伟
傅美平
毛建容
周逢权
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State Grid Corp of China SGCC
Xuji Group Co Ltd
Electric Power Research Institute of State Grid Jiangsu Electric Power Co Ltd
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State Grid Corp of China SGCC
Xuji Group Co Ltd
Electric Power Research Institute of State Grid Jiangsu Electric Power Co Ltd
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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
    • H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P80/00—Climate change mitigation technologies for sector-wide applications
    • Y02P80/10—Efficient use of energy, e.g. using compressed air or pressurized fluid as energy carrier
    • Y02P80/14—District level solutions, i.e. local energy networks

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  • Supply And Distribution Of Alternating Current (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)

Abstract

The invention provides a calculating method and system for the active power shortage of a micro-grid. The method comprises the steps that according to the current frequency f (0) and the target frequency f (1) of the micro-grid, the per unit frequency deviation delta f*(0) of the current frequency and the per unit frequency deviation delta f*(1) of the target frequency are calculated respectively; active adjusting coefficients KGi* and KLj* of each rotating power source i and each load j at the frequencies are calculated by means of the formula (1) of the delta f*(0); the current active power PGi(0) and the rated active power PGi(N) of each rotating power source and the current active power PLj(0) and the rated active power PLj(N) of each load j are known quantities; the unit adjusting power KM of the micro-grid is obtained by means of the formula (8), wherein m is the number of the rotating power sources in the micro-grid, and n is the number of the loads in the micro-grid; the active power shortage PE+ of the micro-grid system from the frequency f (0) to the frequency f (1) is obtained through the formula (9). When the frequencies are abnormal, the active power shortage of the micro-grid can be rapidly and accurately worked out. The active power is adjusted according to the active power shortage, and therefore the micro-grid operation is stabilized.

Description

Method and system for calculating active power shortage of micro-grid
Technical Field
The invention relates to the technical field of microgrid control, in particular to a method and a system for calculating active power shortage of a microgrid.
Background
Under the double pressure of energy crisis and environmental protection, there is an increasing interest in using Distributed Electrical Resource (DER) based renewable energy sources for power supply. However, the distributed power supply such as wind and light has great intermittency and fluctuation, and if the distributed power supply is directly incorporated into a large power grid, the distributed power supply can cause great impact on the safe and stable operation of the large power grid.
Therefore, in most cases, the distributed power supply adopts a mode of independent networking power supply, and is only suitable for some power users with low requirements on power quality and continuous power supply time, and the utilization efficiency of the power is very low. In order to enable distributed energy sources to be merged into a large power grid for operation and improve the utilization rate of the distributed energy sources, the impact of the fluctuation of the distributed energy sources on the power supply quality of the large power grid must be solved, so that a new power grid structure and technology, namely a microgrid, appear.
A microgrid is a local distribution system consisting of a coincidence and a distributed power source in close association. The power supply inside the microgrid contains a large number of power electronic devices and contains various energy sources (wind, light, gas, etc.) and various energy output forms (electricity, heat, cold, etc.).
When the micro-grid and the main grid are disconnected suddenly due to a fault, the micro-grid can generate power independently to maintain the power supply to the user; when the external fault disappears, the micro-grid can automatically recover the grid-connected operation state. That is, the microgrid may be operated either on-grid or off-grid.
When the micro-grid runs off the grid, the normal stability of the voltage and the frequency in the grid must be maintained in real time, and high-quality electric energy is provided.
The safe and stable operation of the power grid is realized in two aspects: firstly, the frequency is stable, and the fluctuation amplitude is not more than +/-0.2-0.5 Hz; secondly, the voltage is stable, and the fluctuation amplitude does not exceed +/-5%.
In practice, the frequency stability within the grid is mainly determined by the active power supply conditions and the voltage stability is mainly determined by the reactive power supply conditions.
Therefore, those skilled in the art need to provide a method and a system for calculating the active power shortage of the microgrid, which can accurately obtain the active power shortage existing in the system when the off-grid frequency in the microgrid is abnormal.
Disclosure of Invention
The invention aims to provide a method and a system for calculating the active power shortage of a micro-grid, which can accurately obtain the active power shortage existing in the system when the off-grid frequency in the micro-grid is abnormal.
The embodiment of the invention provides a method for calculating the active power shortage of a micro-grid, which comprises the following steps:
according to the current frequency f of the microgrid(0)And a target frequency f(1)Respectively calculating per unit frequency deviation of current frequencyPer unit frequency deviation from target frequencyf(0)And f(1)Are all known amounts;
by using the saidAnd the following formula (1) calculates the active regulation coefficient K of each rotating power supply i and each load j in frequencyGi*And KLj*；
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>
Wherein,current active power of each rotating power supply iAnd rated active powerCurrent active power of each load jAnd rated active powerAre all known amounts;
by KGi*And KLj*By the formulaObtaining unit regulation power K of micro-gridM(ii) a Wherein m is the number of rotating power supplies in the micro-grid, and n is the number of loads in the micro-grid;
by the formulaObtaining a slave frequency f of a microgrid system(0)To f(1)Active power shortage P ofE+。
Preferably, the first and second electrodes are formed of a metal,
the above-mentioned <math> <mrow> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>,</mo> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>;</mo> </mrow> </math>
Wherein f is(N)The nominal frequency for the microgrid is a known quantity.
Preferably, theObtaining the current output voltage and current of each rotating power supply;
the above-mentionedObtained from the present voltage and current of each load.
The embodiment of the invention provides a system for calculating the active power shortage of a micro-grid, which comprises the following components: the device comprises a per-unit frequency deviation obtaining unit, an active regulation coefficient obtaining unit, a micro-grid unit regulation power obtaining unit and an active power shortage obtaining unit;
the per-unit frequency deviation obtaining unit is used for obtaining the current frequency f of the micro-grid(0)And a target frequency f(1)Respectively calculating per unit frequency deviation of current frequencyPer unit frequency deviation from target frequencyf(0)And f(1)Are all known amounts;
the active power regulation coefficient obtaining unit is used for utilizing the active power regulation coefficientAnd the following formula (1) calculates the active regulation coefficient K of each rotating power supply i and each load j in frequencyGi*And KLj*；
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>
Wherein,current active power of each rotating power supply iAnd rated active powerCurrent active power of each load jAnd rated active powerAre all known amounts;
the micro-grid unit regulating power obtaining unit is used for utilizing KGi*And KLj*By the formulaObtaining unit regulation power K of micro-gridM(ii) a Wherein m is the number of rotating power supplies in the micro-grid, and n is the number of loads in the micro-grid;
the active power shortage obtaining unit is used for obtaining the shortage of the active powerObtaining a slave frequency f of a microgrid system(0)To f(1)Active power shortage P ofE+。
Preferably, the first and second electrodes are formed of a metal,
the above-mentioned <math> <mrow> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>,</mo> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>;</mo> </mrow> </math>
Wherein f is(N)The nominal frequency for the microgrid is a known quantity.
Preferably, the method further comprises the following steps: the method comprises the steps that a current active power obtaining unit of a rotating power supply and a current active power obtaining unit of a load are arranged;
a present active power obtaining unit of the rotary power supplies for obtaining a present output voltage and an output current of each rotary power supply
A present active power obtaining unit of the loads for obtaining a present voltage and current of each load
Compared with the prior art, the invention has the following advantages:
when a rotating power supply in the micro-grid is used as a main power supply to carry out off-grid operation, the calculation of the active power shortage has important significance for the frequency stability control of the micro-grid. According to the method provided by the embodiment, when the frequency is abnormal, the shortage of the active power of the micro-grid is rapidly and accurately calculated. And correspondingly adjusting the active power output by the rotating power supply and the active power of the load according to the calculated active power shortage, thereby stabilizing the operation of the whole microgrid. The method improves the regulation mode of the active power of the microgrid from qualitative regulation to quantitative regulation. And the influence of the switching of each active device (including a rotating power supply and a load) in the microgrid on the fluctuation of the frequency in the microgrid is considered, so that the safety stability of the frequency is considered.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a flow chart of an embodiment of a method for calculating an active power shortage of a microgrid provided by the present invention;
FIG. 2 is a graph of the static frequency characteristics of a rotating power supply and load provided by the present invention;
FIG. 3 is a flowchart of an embodiment of a method for calculating an active power shortage of a microgrid provided by the present invention;
FIG. 4 is a schematic diagram of an embodiment of a system for calculating an active power shortage of a microgrid provided by the invention;
fig. 5 is a schematic diagram of a second embodiment of the active power shortage calculation system of the microgrid provided by the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
The first embodiment of the method comprises the following steps:
referring to fig. 1, the figure is a flowchart of an embodiment of a method for calculating an active power shortage of a microgrid provided by the present invention.
In order to better understand the technical solution of the present invention for those skilled in the art, first, the basic principle of the present invention will be described.
Referring to fig. 2, a graph of the static frequency characteristics of a rotating power supply and a load according to the present invention is shown.
It will be appreciated that there are operational rotary power supplies, loads and power electronic power supplies in microgrid systems operating off-grid.
For example, the rotary power source may be a rotary generator.
As can be seen from FIG. 2, the abscissa is the per unit value of frequency, expressed as f*And (4) showing. The ordinate is the per unit value of active power, P*And (4) showing.
P in FIG. 2G*(f) Expressing the active power per unit value, P, of the rotating power supply at frequency fL*(f) And expressing the active power per unit value of the load at the frequency f.
As can be seen from the characteristic curve shown in fig. 2, the active power P of the loadL*(f) With frequencyf is increased and becomes larger, and the static frequency adjustment effect coefficient K of the load is increasedLd*>0; active power P output by rotating power supplyG*(f) Decreases with increasing frequency f; i.e. the static frequency adjustment direction for the rotating power supply and the load is exactly opposite.
For the power electronic power supply, the output active power of the power electronic power supply is automatically adjusted by a power electronic equipment control device (PCS) according to an instruction issued by control, and the PCS detects the output active power of the related power supply at any time and adjusts the active power to be close to a command value at any time, so that the output active power of the power electronic power supply is irrelevant to the frequency of the microgrid, and the static power adjustment effect coefficient of the power electronic power supply is considered to be 0, namely KG*＝0。
Therefore, in the invention, for the calculation of the active power shortage of the micro-grid, only the active power shortage of the rotating power supply and the load when the frequency changes is considered, and the active power shortage of the power electronic power supply is not considered.
The method for calculating the active power shortage of the microgrid provided by the embodiment comprises the following steps:
s101: according to the current frequency f of the microgrid(0)And a target frequency f(1)Respectively calculating per unit frequency deviation of current frequencyPer unit frequency deviation from target frequencyf(0)And f(1)Are all known amounts;
it will be appreciated that the <math> <mrow> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>,</mo> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>;</mo> </mrow> </math>
Wherein f is(N)The nominal frequency for the microgrid is a known quantity.
In the examples of the present invention, a unit value is represented by a subscript.
S102: by using the saidAnd the following formula (1) calculates the active regulation coefficient K of each rotating power supply i and each load j in frequencyGi*And KLj*；
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>
Wherein,current active power of each rotating power supply iAnd rated active powerCurrent active power of each load jAnd rated active powerAre all known amounts;
in S102, only P needs to be calculatedGi*(f(0)) And PLj*(f(0)) Only need to utilizeAnd
s103: by KGi*And KLj*By the formulaObtaining unit regulation power K of micro-gridM(ii) a Wherein m is the number of rotating power supplies in the micro-grid, and n is the number of loads in the micro-grid;
wherein, P Gi * ( 0 ) = P Gi ( 0 ) P Gi ( N ) , P Lj * ( 0 ) = P Lj ( 0 ) P Lj ( N ) .
since the micro-grid system includes a plurality of rotating power supplies and a plurality of loads, it is necessary to add the active power adjustment powers corresponding to the rotating power supplies and the loads.
S104: by the formulaObtaining a slave frequency f of a microgrid system(0)To f(1)Active power shortage P ofE+。
When a rotating power supply in the micro-grid is used as a main power supply to carry out off-grid operation, the calculation of the active power shortage has important significance for the frequency stability control of the micro-grid. According to the method provided by the embodiment, when the frequency is abnormal, the shortage of the active power of the micro-grid is rapidly and accurately calculated. And correspondingly adjusting the active power output by the rotating power supply and the active power of the load according to the calculated active power shortage, thereby stabilizing the operation of the whole microgrid. The method improves the regulation mode of the active power of the microgrid from qualitative regulation to quantitative regulation. And the influence of the switching of each active device (including a rotating power supply and a load) in the microgrid on the fluctuation of the frequency in the microgrid is considered, so that the safety stability of the frequency is considered.
The second method embodiment:
referring to fig. 3, it is a flowchart of an embodiment of a method for calculating an active power shortage of a microgrid provided by the present invention.
S301 in this embodiment is the same as S101, and S302-S305 are the same as S102-S104, respectively, and are not described herein again.
For rotating power supplies and loads, the active power can be calculated from their corresponding voltages and currents.
S302: the above-mentionedObtaining the current output voltage and current of each rotating power supply; the above-mentionedObtained from the present voltage and current of each load.
The derivation process of the formula (1) is explained below.
The unit regulation power of a single rotating power supply i and a single load j is respectively set as Then when the frequency is changed from the initial frequency f(0)Becomes the target frequency f(1)After that, there are:
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>-</mo> <msub> <mi>K</mi> <mi>Gi</mi> </msub> <mo>&CenterDot;</mo> <mi>&Delta;</mi> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1,0</mn> <mo>)</mo> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>+</mo> <msub> <mi>K</mi> <mi>Lj</mi> </msub> <mo>&CenterDot;</mo> <mi>&Delta;</mi> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1,0</mn> <mo>)</mo> </mrow> </msup> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>2</mn> <mo>)</mo> </mrow> </mrow> </math>
wherein, Δ f(1,0)＝f(1)-f(0)。
The rated frequency active power of a rotating power supply i and a load j are respectively set asOrder to K Lj ( N ) = P Lj ( N ) f ( N ) , Is provided with K Gi * = K Gi K Gi ( N ) , K Lj * = K Lj K Lj ( N ) . Therefore, there are:
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>K</mi> <mi>Gi</mi> </msub> <mo>=</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mo>&CenterDot;</mo> <msubsup> <mi>K</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mo>&CenterDot;</mo> <mfrac> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> </mtd> </mtr> <mtr> <mtd> <msub> <mi>K</mi> <mi>Lj</mi> </msub> <mo>=</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mo>&CenterDot;</mo> <msubsup> <mi>K</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mo>&CenterDot;</mo> <mfrac> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>3</mn> <mo>)</mo> </mrow> </mrow> </math>
let f(0)＝f(N)，f(1)When the formula (3) is substituted into the formula (2), and both ends of the substituted equation (2) and the like are divided by the rated frequency active power, the following equation (3) can be obtained:
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>
it should be noted that the above-described equations (1), (2) and (3) are all described in terms of the active characteristics of a single device, wherein the device includes a rotating power source and a load.
The overall active characteristics of the active devices in the microgrid system are described below.
Since the active devices in the microgrid system comprise a plurality of active devices, the active devices are in particular a superposition of a plurality of devices.
Obtaining the active characteristics of the system according to the formula (2), such as the formula (4);
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <munder> <mi>&Sigma;</mi> <mi>i</mi> </munder> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <munder> <mi>&Sigma;</mi> <mi>i</mi> </munder> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>-</mo> <munder> <mi>&Sigma;</mi> <mi>i</mi> </munder> <msub> <mi>K</mi> <mi>Gi</mi> </msub> <mo>&CenterDot;</mo> <mi>&Delta;f</mi> </mtd> </mtr> <mtr> <mtd> <munder> <mi>&Sigma;</mi> <mi>j</mi> </munder> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <munder> <mi>&Sigma;</mi> <mi>j</mi> </munder> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>+</mo> <munder> <mi>&Sigma;</mi> <mi>j</mi> </munder> <msub> <mi>K</mi> <mi>Lj</mi> </msub> <mo>&CenterDot;</mo> <mi>&Delta;f</mi> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>4</mn> <mo>)</mo> </mrow> </mrow> </math>
the unit regulation power coefficient of the system can be obtained by formula (3), such as formula (5);
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>K</mi> <mrow> <mi>G</mi> <mo>*</mo> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <munder> <mi>&Sigma;</mi> <mi>i</mi> </munder> <msub> <mi>K</mi> <mi>Gi</mi> </msub> </mrow> <msubsup> <mi>K</mi> <mi>G</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> </mfrac> <mo>=</mo> <mfrac> <mrow> <munder> <mi>&Sigma;</mi> <mi>i</mi> </munder> <mrow> <mo>(</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mo>&CenterDot;</mo> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <mo>)</mo> </mrow> </mrow> <mrow> <munder> <mi>&Sigma;</mi> <mi>i</mi> </munder> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> </mrow> </mfrac> </mtd> </mtr> <mtr> <mtd> <msub> <mi>K</mi> <mrow> <mi>L</mi> <mo>*</mo> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <munder> <mi>&Sigma;</mi> <mi>j</mi> </munder> <msub> <mi>K</mi> <mi>Lj</mi> </msub> </mrow> <msubsup> <mi>K</mi> <mi>L</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> </mfrac> <mo>=</mo> <mfrac> <mrow> <munder> <mi>&Sigma;</mi> <mi>j</mi> </munder> <mrow> <mo>(</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mo>&CenterDot;</mo> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <mo>)</mo> </mrow> </mrow> <mrow> <munder> <mi>&Sigma;</mi> <mi>j</mi> </munder> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> </mrow> </mfrac> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>5</mn> <mo>)</mo> </mrow> </mrow> </math>
formula (5) is the per unit power adjustment value K of the total rotating power supply unit of the micro-grid systemG*And total load static frequency regulation effect coefficient KL*The formula (2) is calculated.
Equation (4) can be simplified from equation (5) as follows:
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>P</mi> <mi>G</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <msubsup> <mi>P</mi> <mi>G</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>G</mi> <mo>*</mo> </mrow> </msub> <msubsup> <mi>P</mi> <mi>G</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msubsup> <mi>P</mi> <mi>L</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <msubsup> <mi>P</mi> <mi>L</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>L</mi> <mo>*</mo> </mrow> </msub> <msubsup> <mi>P</mi> <mi>L</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msubsup> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>6</mn> <mo>)</mo> </mrow> </mrow> </math>
according to the total rated power of the micro-grid systemAndcan be obtained f(1)、f(0)The following active power relationship is:
P G ( 1 ) = P G * ( 1 ) P G * ( 0 ) P G ( 0 ) P L ( 1 ) = P L * ( 1 ) P L * ( 0 ) P L ( 0 ) - - - ( 7 )
calculating the unit regulated power K of the microgrid according to the formula (5) and the formula (7)M。
<math> <mrow> <msub> <mi>K</mi> <mi>M</mi> </msub> <mo>=</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>m</mi> </munderover> <mfrac> <mrow> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <msubsup> <mi>P</mi> <mi>Gi</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> </mrow> <msubsup> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> </mfrac> <mo>+</mo> <munderover> <mi>&Sigma;</mi> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <mfrac> <mrow> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <msubsup> <mi>P</mi> <mi>Lj</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> </mrow> <msubsup> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> </mfrac> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>8</mn> <mo>)</mo> </mrow> </mrow> </math>
The micro grid system slave frequency f(0)To f(1)Active power shortage P ofE+Comprises the following steps:
<math> <mrow> <msub> <mi>P</mi> <mrow> <mi>E</mi> <mo>+</mo> </mrow> </msub> <mo>=</mo> <msub> <mi>K</mi> <mi>M</mi> </msub> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1,0</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <msub> <mi>K</mi> <mi>M</mi> </msub> <mrow> <mo>(</mo> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>-</mo> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>9</mn> <mo>)</mo> </mrow> </mrow> </math>
based on the method for calculating the active power shortage of the microgrid provided by the embodiment, the embodiment of the invention also provides a system for calculating the active power shortage of the microgrid, and the method is described in detail below with reference to the attached drawings.
The first embodiment of the system:
referring to fig. 4, the figure is a schematic diagram of an embodiment of a computing system for an active power shortage of a microgrid provided by the present invention.
The embodiment of the invention provides a system for calculating the active power shortage of a micro-grid, which comprises the following components: a per-unit frequency deviation obtaining unit 401, an active power regulation coefficient obtaining unit 402, a microgrid unit regulation power obtaining unit 403 and an active power shortage obtaining unit 404;
the per-unit frequency deviation obtaining unit 401 is configured to obtain a current frequency f of the microgrid according to the per-unit frequency deviation(0)And a target frequency f(1)Respectively calculating per unit frequency deviation of current frequencyPer unit frequency deviation from target frequencyf(0)And f(1)Are all known amounts;
it will be appreciated that there are operational rotary power supplies, loads and power electronic power supplies in microgrid systems operating off-grid.
For example, the rotary power source may be a rotary generator.
It will be appreciated that the <math> <mrow> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>,</mo> <mi>&Delta;</mi> <msubsup> <mi>f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>;</mo> </mrow> </math>
Wherein f is(N)The nominal frequency for the microgrid is a known quantity.
In the examples of the present invention, a unit value is represented by a subscript.
The active regulation coefficient obtaining unit 402 is configured to utilize the active regulation coefficientAnd the following formula (1) calculates the active regulation coefficient K of each rotating power supply i and each load j in frequencyGi*And KLj*；
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mi>&Delta;</mi> <msub> <mi>f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>
Wherein,current active power of each rotating power supply iAnd rated active powerCurrent active power of each load jAnd rated active powerAre all known amounts;
it should be noted that only P needs to be calculatedGi*(f(0)) And PLj*(f(0)) Only need to utilizeAnd
the microgrid unit regulation power obtaining unit 403 is used for utilizing KGi*And KLj*By the formulaObtaining unit regulation power K of micro-gridM(ii) a Wherein m is the number of rotating power supplies in the micro-grid, and n is the number of loads in the micro-grid;
wherein, P Gi * ( 0 ) = P Gi ( 0 ) P Gi ( N ) , P Lj * ( 0 ) = P Lj ( 0 ) P Lj ( N ) .
since the micro-grid system includes a plurality of rotating power supplies and a plurality of loads, it is necessary to add the active power adjustment powers corresponding to the rotating power supplies and the loads.
The active power shortage obtaining unit 404 is used for obtaining the active power shortage according to the formulaObtaining a slave frequency f of a microgrid system(0)To f(1)Active power shortage P ofE+。
When a rotating power supply in the micro-grid is used as a main power supply to carry out off-grid operation, the calculation of the active power shortage has important significance for the frequency stability control of the micro-grid. According to the method provided by the embodiment, when the frequency is abnormal, the shortage of the active power of the micro-grid is rapidly and accurately calculated. And correspondingly adjusting the active power output by the rotating power supply and the active power of the load according to the calculated active power shortage, thereby stabilizing the operation of the whole microgrid. The method improves the regulation mode of the active power of the microgrid from qualitative regulation to quantitative regulation. And the influence of the switching of each active device (including a rotating power supply and a load) in the microgrid on the fluctuation of the frequency in the microgrid is considered, so that the safety stability of the frequency is considered.
The second embodiment of the system:
referring to fig. 5, the second schematic view of the embodiment of the active power shortage calculation system of the microgrid provided by the invention is shown.
The active power shortage calculation system of the microgrid provided by the embodiment further comprises: a current active power obtaining unit 501 of the rotating power supply and a current active power obtaining unit 502 of the load;
for rotating power supplies and loads, the active power can be calculated from their corresponding voltages and currents.
A present active power obtaining unit 501 of the rotary power supplies for obtaining a present output voltage and an output current of each rotary power supply
A present active power obtaining unit 502 of the loads for obtaining from the present voltage and current of each load
The method and the system provided by the embodiment can quickly calculate the corresponding active power shortage in the micro-grid system when the frequency changes, and further can perform corresponding control according to the calculated active power shortage, so that the micro-grid system can work in a stable state.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.

Claims (6)

1. A method for calculating active power shortage of a microgrid is characterized by comprising the following steps:
according to the current frequency f of the microgrid(0)And a target frequency f(1)Respectively calculating per unit frequency deviation of current frequencyPer unit frequency deviation from target frequencyf(0)And f(1)Are all known amounts;
by using the saidAnd the following formula (1) calculates the active regulation coefficient K of each rotating power supply i and each load j in frequencyGi*And KLj*；
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <msub> <mi>&Delta;f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <msub> <mi>&Delta;f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>
Wherein,current active power of each rotating power supply iAnd rated active powerCurrent active power of each load jAnd rated active powerAre all known amounts;
by KGiA and KLj*By the formulaObtaining unit regulation power K of micro-gridM(ii) a Wherein m is the number of rotating power supplies in the micro-grid, and n is the number of loads in the micro-grid;
by the formulaObtaining a slave frequency f of a microgrid system(0)To f(1)Active power shortage P ofE+。
2. The method for calculating the active power shortage of a microgrid according to claim 1,
the above-mentioned <math> <mrow> <msubsup> <mi>&Delta;f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>,</mo> <msubsup> <mi>&Delta;f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>;</mo> </mrow> </math>
Wherein f is(N)The nominal frequency for the microgrid is a known quantity.
3. Method for calculating the active power shortage of a microgrid according to claim 1 or 2, characterised in that said method comprises the steps ofObtaining the current output voltage and current of each rotating power supply;
the above-mentionedObtained from the present voltage and current of each load.
4. A system for calculating active power deficit in a microgrid, comprising: the device comprises a per-unit frequency deviation obtaining unit, an active regulation coefficient obtaining unit, a micro-grid unit regulation power obtaining unit and an active power shortage obtaining unit;
the per-unit frequency deviation obtaining unit is used for obtaining the current frequency f of the micro-grid(0)And a target frequency f(1)Respectively calculating per unit frequency deviation of current frequencyPer unit frequency deviation from target frequencyf(0)And f(1)Are all known amounts;
the active power regulation coefficient obtaining unit is used for utilizing the active power regulation coefficientAnd the following formula (1) calculates the active regulation coefficient K of each rotating power supply i and each load j in frequencyGi*And KLj*；
<math> <mrow> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>-</mo> <msub> <mi>K</mi> <mrow> <mi>Gi</mi> <mo>*</mo> </mrow> </msub> <msub> <mi>&Delta;f</mi> <mo>*</mo> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>P</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <mrow> <mo>(</mo> <mi>f</mi> <mo>)</mo> </mrow> <mo>=</mo> <mn>1</mn> <mo>+</mo> <msub> <mi>K</mi> <mrow> <mi>Lj</mi> <mo>*</mo> </mrow> </msub> <msub> <mi>&Delta;f</mi> <mo>*</mo> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </mrow> </math>
Wherein,current active power of each rotating power supply iAnd rated active powerCurrent active power of each load jAnd rated active powerAre all known amounts;
the micro-grid unit regulating power obtaining unit is used for utilizing KGi*And KLj*By the formulaObtaining unit regulation power K of micro-gridM(ii) a Wherein m isThe number of the rotating power supplies in the micro-grid is n, and the number of the loads in the micro-grid is n;
the active power shortage obtaining unit is used for obtaining the shortage of the active powerObtaining a slave frequency f of a microgrid system(0)To f(1)Active power shortage P ofE+。
5. The active power shortage calculation system of a microgrid according to claim 4, characterized in that,
the above-mentioned <math> <mrow> <msubsup> <mi>&Delta;f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>0</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>,</mo> <msubsup> <mi>&Delta;f</mi> <mo>*</mo> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msubsup> <mo>=</mo> <mfrac> <mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mn>1</mn> <mo>)</mo> </mrow> </msup> <mo>-</mo> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mrow> <msup> <mi>f</mi> <mrow> <mo>(</mo> <mi>N</mi> <mo>)</mo> </mrow> </msup> </mfrac> <mo>;</mo> </mrow> </math>
Wherein f is(N)The nominal frequency for the microgrid is a known quantity.
6. The active power shortage calculation system of the microgrid of claim 4 or 5, further comprising: the method comprises the steps that a current active power obtaining unit of a rotating power supply and a current active power obtaining unit of a load are arranged;
a present active power obtaining unit of the rotary power supplies for obtaining a present output voltage and an output current of each rotary power supply
A present active power obtaining unit of the loads for obtaining a present voltage and current of each load
CN201410601609.4A 2014-10-30 2014-10-30 Calculating method and system for active power shortage of micro-grid Expired - Fee Related CN104300558B (en)

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