CN104300558A - Calculation method and system for active power deficit of a microgrid - Google Patents

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

Calculation method and system for active power deficit of a microgrid

technical field

The invention relates to the technical field of micro-grid control, in particular to a method and system for calculating active power shortage of a micro-grid.

Background technique

Under the dual pressure of energy crisis and environmental protection, the use of renewable energy-based distributed power generation (DER, Distributed Electric Resource) power supply has attracted more and more attention. However, distributed power sources such as wind and light have great intermittency and volatility. If they are directly incorporated into the large power grid, it will have a great impact on the safe and stable operation of the large power grid.

Therefore, in most cases, the distributed power supply adopts a separate network power supply method, which can only be applied to some power users who have low requirements for power quality and continuous power supply time, and the utilization efficiency of power energy is very low. In order to integrate distributed energy into the large power grid and improve the utilization rate of distributed energy, it is necessary to solve the impact of distributed energy volatility on the power supply quality of the large power grid, and a new grid structure and technology has emerged. That is the microgrid.

A microgrid is a local power distribution system that is closely combined with distributed power sources. The power supply inside the microgrid contains a large number of power electronic devices, and contains a variety of energy sources (wind, light, gas, etc.) and various energy output forms (electricity, heat, cold, etc.).

When the microgrid and the main grid are suddenly disconnected due to a fault, the microgrid can generate electricity independently to maintain the power supply to its own users; when the external fault disappears, the microgrid can also automatically restore the grid-connected operation state. That is, the microgrid can operate both on-grid and off-grid.

When the microgrid realizes off-grid operation, it must maintain the normal and stable voltage and frequency in the grid in real time to provide high-quality electric energy.

The safe and stable operation of the power grid is reflected in two aspects: one is the frequency stability, the fluctuation range does not exceed ±0.2~0.5Hz; the other is the voltage stability, the fluctuation range does not exceed ±5%.

In fact, the frequency stability in the grid is mainly determined by the active power supply status, and the voltage stability is mainly determined by the reactive power supply status.

Therefore, those skilled in the art need to provide a method and system for calculating the active power deficit of the microgrid, which can accurately obtain the active power deficit existing in the system when the off-grid frequency in the microgrid is abnormal.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method and system for calculating the active power deficit of the microgrid, which can accurately obtain the active power deficit existing in the system when the off-grid frequency in the microgrid is abnormal.

An embodiment of the present invention provides a method for calculating the active power deficit of a microgrid, including:

According to the current frequency f ⁽⁰⁾ and the target frequency f ⁽¹⁾ of the microgrid, calculate the per-unit frequency deviation of the current frequency per unit frequency deviation from the target frequency Both f ⁽⁰⁾ and f ⁽¹⁾ are known quantities;

use the and the following formula (1) calculates the active power adjustment coefficients K _Gi* and K _Lj* of each rotating power source i and each load j at frequency;

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

in, The current active power of each rotating source i and rated active power The current active power of each load j and rated active power are known quantities;

Using K _Gi* and K _Lj* by the formula Obtain the micro-grid unit regulation power K _M ; where m is the number of rotating power sources in the micro-grid, and n is the number of loads in the micro-grid;

by the formula Obtain the active power deficit P _E+ of the microgrid system from frequency f ⁽⁰⁾ to f ⁽¹⁾ .

Preferably,

said $\mathrm{\&Delta;}{f}_{*}^{\left(0\right)}=\frac{f^{\left(0\right)}-f^{\left(N\right)}}{f^{\left(N\right)}},\mathrm{\&Delta;}{f}_{*}^{\left(1\right)}=\frac{f^{\left(1\right)}-f^{\left(N\right)}}{f^{\left(N\right)}};$

Among them, f ^(N) is a known quantity of the rated frequency of the microgrid.

Preferably, the Obtained from the current output voltage and output current of each rotating power supply;

said Obtained from the current voltage and current of each load.

An embodiment of the present invention provides a calculation system for the active power deficit of a microgrid, including: a per-unit frequency deviation acquisition unit, an active power adjustment coefficient acquisition unit, a microgrid unit adjustment power acquisition unit, and an active power deficit acquisition unit;

The per unit frequency deviation obtaining unit is used to calculate the per unit frequency deviation of the current frequency according to the current frequency f ⁽⁰⁾ and the target frequency f ⁽¹⁾ of the microgrid respectively per unit frequency deviation from the target frequency Both f ⁽⁰⁾ and f ⁽¹⁾ are known quantities;

The active power adjustment coefficient obtaining unit is used to utilize the and the following formula (1) calculates the active power adjustment coefficients K _Gi* and K _Lj* of each rotating power source i and each load j at frequency;

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

in, The current active power of each rotating source i and rated active power The current active power of each load j and rated active power are known quantities;

The microgrid unit adjusts the power harvesting unit for utilizing K _Gi* and K _Lj* by the formula Obtain the micro-grid unit regulation power K _M ; where m is the number of rotating power sources in the micro-grid, and n is the number of loads in the micro-grid;

The active power deficit obtaining unit is used for the formula Obtain the active power deficit P _E+ of the microgrid system from frequency f ⁽⁰⁾ to f ⁽¹⁾ .

Preferably,

said $\mathrm{\&Delta;}{f}_{*}^{\left(0\right)}=\frac{f^{\left(0\right)}-f^{\left(N\right)}}{f^{\left(N\right)}},\mathrm{\&Delta;}{f}_{*}^{\left(1\right)}=\frac{f^{\left(1\right)}-f^{\left(N\right)}}{f^{\left(N\right)}};$

Among them, f ^(N) is a known quantity of the rated frequency of the microgrid.

Preferably, it also includes: the current active power acquisition unit of the rotating power supply and the current active power acquisition unit of the load;

The current active power obtaining unit of the rotating power source is used to obtain the current active power from the current output voltage and output current of each rotating power source

The current active power obtaining unit of the load is used to obtain the current active power of each load from the current voltage and current

Compared with the prior art, the present invention has the following advantages:

When the rotating power supply is used as the main power source in the microgrid for off-grid operation, the calculation of the active power deficit is of great significance for the frequency stability control of the microgrid. The method provided in this embodiment can quickly and accurately calculate the shortfall of the active power of the microgrid when the frequency is abnormal. According to the calculated active power deficit, the active power output by the rotating power supply and the active power of the load are adjusted accordingly, so as to stabilize the operation of the entire microgrid. This method improves the adjustment mode of the active power of the microgrid from qualitative adjustment to quantitative adjustment. Moreover, considering the influence of the switching of each active device (including rotating power supply and load) in the microgrid on the frequency fluctuation in the microgrid, the safety and stability of the frequency is considered.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the flow chart of the first embodiment of the calculation method of the active power deficit of the microgrid provided by the present invention;

Fig. 2 is the static frequency characteristic curve diagram of rotating power supply and load provided by the present invention;

Fig. 3 is the flow chart of Embodiment 2 of the calculation method for the active power deficit of the microgrid provided by the present invention;

Fig. 4 is a schematic diagram of Embodiment 1 of the calculation system of the active power deficit of the microgrid provided by the present invention;

Fig. 5 is a schematic diagram of Embodiment 2 of the calculation system for the active power deficit of the microgrid provided by the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.

Method embodiment one:

Referring to FIG. 1 , this figure is a flow chart of Embodiment 1 of the method for calculating the active power deficit of the microgrid provided by the present invention.

In order for those skilled in the art to better understand the technical solutions of the present invention, the basic principles of this field are firstly introduced.

Referring to Fig. 2, this figure is a static frequency characteristic curve diagram of the rotating power supply and load provided by the present invention.

It is understandable that there are rotating power sources, loads and power electronic sources in operation in the off-grid microgrid system.

For example, the rotating power source may be a rotating generator.

It can be seen from Figure 2 that the abscissa is the per-unit value of the frequency, represented by f _* . The ordinate is the per unit value of active power, represented by P _* .

PG _* (f) in Figure 2 represents the active power per unit value of the rotating power supply at frequency f, and P _L* (f) represents the per unit active power value of the load at frequency f.

From the characteristic curve shown in Figure 2, it can be seen that the active power P _L* (f) of the load increases with the increase of the frequency f, and the static frequency regulation effect coefficient of the load K _Ld* >0; the rotating power output The active power P _G* (f) decreases with the increase of frequency f; that is, the direction of static frequency adjustment for rotating power supply and load is just opposite.

For the power electronic power supply, its output active power is automatically adjusted by the power electronic equipment control device (PCS) according to the instructions issued by the control. The active power output by the electronic power supply has nothing to do with the frequency of the microgrid, and its static power adjustment effect coefficient can be considered to be 0, ie, K _G* =0.

Therefore, in the present invention, for the calculation of the active power deficit of the microgrid, only the active power deficit of the rotating power supply and the load when the frequency changes is considered, and the active power deficit of the power electronic power supply is not considered.

The method for calculating the active power deficit of the microgrid provided in this embodiment includes:

S101: Calculate the per unit frequency deviation of the current frequency according to the current frequency f ⁽⁰⁾ and the target frequency f ⁽¹⁾ of the microgrid per unit frequency deviation from the target frequency Both f ⁽⁰⁾ and f ⁽¹⁾ are known quantities;

Understandably, the $\mathrm{\&Delta;}{f}_{*}^{\left(0\right)}=\frac{f^{\left(0\right)}-f^{\left(N\right)}}{f^{\left(N\right)}},\mathrm{\&Delta;}{f}_{*}^{\left(1\right)}=\frac{f^{\left(1\right)}-f^{\left(N\right)}}{f^{\left(N\right)}};$

Among them, f ^(N) is a known quantity of the rated frequency of the microgrid.

In the embodiment of the present invention, the subscript * is used to represent the per unit value.

S102: Using the and the following formula (1) calculates the active power adjustment coefficients K _Gi* and K _Lj* of each rotating power source i and each load j at frequency;

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

in, The current active power of each rotating source i and rated active power The current active power of each load j and rated active power are known quantities;

It should be noted that only P _Gi* (f ⁽⁰⁾ ) and P _Lj* (f ⁽⁰⁾ ) need to be calculated in S102, therefore, only need to use and

S103: Using K _Gi* and K _Lj* from the formula Obtain the micro-grid unit regulation power K _M ; where m is the number of rotating power sources in the micro-grid, and n is the number of loads in the micro-grid;

in, $P_{\mathrm{Gi}*}^{\left(0\right)}=\frac{{P_{\mathrm{Gi}}}^{\left(0\right)}}{{P_{\mathrm{Gi}}}^{\left(N\right)}},P_{\mathrm{Lj}*}^{\left(0\right)}=\frac{{P_{\mathrm{Lj}}}^{\left(0\right)}}{{P_{\mathrm{Lj}}}^{\left(N\right)}}.$

Since the microgrid system includes multiple rotating power sources and multiple loads, it is necessary to add the active power adjustment power corresponding to these rotating power sources and loads.

S104: by the formula Obtain the active power deficit P _E+ of the microgrid system from frequency f ⁽⁰⁾ to f ⁽¹⁾ .

When the rotating power supply is used as the main power source in the microgrid for off-grid operation, the calculation of the active power deficit is of great significance for the frequency stability control of the microgrid. The method provided in this embodiment can quickly and accurately calculate the shortfall of the active power of the microgrid when the frequency is abnormal. According to the calculated active power deficit, the active power output by the rotating power supply and the active power of the load are adjusted accordingly, so as to stabilize the operation of the entire microgrid. This method improves the adjustment mode of the active power of the microgrid from qualitative adjustment to quantitative adjustment. Moreover, considering the influence of the switching of each active device (including rotating power supply and load) in the microgrid on the frequency fluctuation in the microgrid, the safety and stability of the frequency is considered.

Method embodiment two:

Refer to FIG. 3 , which is a flow chart of Embodiment 2 of the method for calculating the active power deficit of the microgrid provided by the present invention.

S301 in this embodiment is the same as S101, and S302-S305 are respectively the same as S102-S104, which will not be repeated here.

For rotating power sources and loads, active power can be calculated from their corresponding voltage and current.

S302: said obtained from the current output voltage and output current of each rotary power supply; the Obtained from the current voltage and current of each load.

The derivation process of formula (1) is explained below.

Let the unit regulated power of a single rotating power source i and a single load j be Then when the frequency changes from the initial frequency f ⁽⁰⁾ to the target frequency f ⁽¹⁾ , there are:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1,0</span>}<span\; class="notranslate">\; )</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1,0</span>}<span\; class="notranslate">\; )</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, Δf ^(1,0) =f ⁽¹⁾ −f ⁽⁰⁾ .

Let the rated frequency active power of rotating power source i and load j be make $K_{\mathrm{Lj}}^{\left(N\right)}=\frac{P_{\mathrm{Lj}}^{\left(N\right)}}{f^{\left(N\right)}},$ have $K_{\mathrm{Gi}*}=\frac{K_{\mathrm{Gi}}}{K_{\mathrm{Gi}}^{\left(N\right)}},K_{\mathrm{Lj}*}=\frac{K_{\mathrm{Lj}}}{K_{\mathrm{Lj}}^{\left(N\right)}}.$ So there are:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}\\ {\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&CenterDot;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Suppose f ⁽⁰⁾ ＝f ^(N) , f ⁽¹⁾ ＝f, substituting formula (3) into formula (2), and dividing both ends of equal sign of the substituted formula (2) by rated frequency active power ,Available:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

It should be noted that the formulas (1), (2) and (3) introduced above are all based on the active characteristics of a single device, and the devices include rotating power sources and loads.

The comprehensive active characteristics of the active equipment in the microgrid system are introduced below.

Since there are multiple active devices in the microgrid system, active power is especially the superposition of multiple devices.

According to formula (2), the system active characteristics can be obtained, such as formula (4);

$\left\{\begin{array}{c}\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}\\ \underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&Delta;\; f</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

The unit regulation power coefficient of the system can be obtained from formula (3), such as formula (5);

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}}{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>}{\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}\\ {\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}}{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>}{\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Formula (5) is the calculation formula of the microgrid system's total rotating power unit adjustment power per unit value K _G* and the total load static frequency adjustment effect coefficient K _L* .

From formula (5), formula (4) can be simplified as follows:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; )</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

According to the total rated power of the microgrid system and The active power relationship under f ⁽¹⁾ and f ⁽⁰⁾ can be obtained as:

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; G</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Calculate the microgrid unit regulation power K _M by formula (5) and formula (7).

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\frac{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

Then the active power deficit P _E+ of the microgrid system from frequency f ⁽⁰⁾ to f ⁽¹ ) is:

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}<span\; class="notranslate">\; +</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1,0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

Based on the method for calculating the active power deficit of the microgrid provided by the above embodiments, the embodiment of the present invention also provides a calculation system for the active power deficit of the microgrid, which will be described in detail below with reference to the accompanying drawings.

System embodiment one:

Referring to FIG. 4 , this figure is a schematic diagram of Embodiment 1 of the calculation system for the active power deficit of the microgrid provided by the present invention.

An embodiment of the present invention provides a calculation system for the active power deficit of a microgrid, including: a per unit frequency deviation acquisition unit 401, an active power adjustment coefficient acquisition unit 402, a microgrid unit adjustment power acquisition unit 403, and an active power deficit acquisition unit 404;

The per unit frequency deviation obtaining unit 401 is used to calculate the per unit frequency deviation of the current frequency according to the current frequency f ⁽⁰⁾ and the target frequency f ⁽¹⁾ of the microgrid respectively per unit frequency deviation from the target frequency Both f ⁽⁰⁾ and f ⁽¹⁾ are known quantities;

It is understandable that there are rotating power sources, loads and power electronic sources in operation in the off-grid microgrid system.

For example, the rotating power source may be a rotating generator.

Understandably, the $\mathrm{\&Delta;}{f}_{*}^{\left(0\right)}=\frac{f^{\left(0\right)}-f^{\left(N\right)}}{f^{\left(N\right)}},\mathrm{\&Delta;}{f}_{*}^{\left(1\right)}=\frac{f^{\left(1\right)}-f^{\left(N\right)}}{f^{\left(N\right)}};$

Among them, f ^(N) is a known quantity of the rated frequency of the microgrid.

In the embodiment of the present invention, the subscript * is used to represent the per unit value.

The active power adjustment coefficient obtaining unit 402 is used to utilize the and the following formula (1) calculates the active power adjustment coefficients K _Gi* and K _Lj* of each rotating power source i and each load j at frequency;

$\left\{\begin{array}{c}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Gi</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\\ {\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; Lj</span>}<span\; class="notranslate">\; *</span>}\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}_{<span\; class="notranslate">\; *</span>}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

in, The current active power of each rotating source i and rated active power The current active power of each load j and rated active power are known quantities;

It should be noted that it is only necessary to calculate P _Gi* (f ⁽⁰⁾ ) and P _Lj* (f ⁽⁰⁾ ), therefore, only need to use and

The microgrid unit adjusts the power acquisition unit 403, which is used to use K _Gi* and K _Lj* by the formula Obtain the micro-grid unit regulation power K _M ; where m is the number of rotating power sources in the micro-grid, and n is the number of loads in the micro-grid;

in, $P_{\mathrm{Gi}*}^{\left(0\right)}=\frac{{P_{\mathrm{Gi}}}^{\left(0\right)}}{{P_{\mathrm{Gi}}}^{\left(N\right)}},P_{\mathrm{Lj}*}^{\left(0\right)}=\frac{{P_{\mathrm{Lj}}}^{\left(0\right)}}{{P_{\mathrm{Lj}}}^{\left(N\right)}}.$

Since the microgrid system includes multiple rotating power sources and multiple loads, it is necessary to add the active power adjustment power corresponding to these rotating power sources and loads.

The active power deficit obtaining unit 404 is used for formula Obtain the active power deficit P _E+ of the microgrid system from frequency f ⁽⁰⁾ to f ⁽¹⁾ .

When the rotating power supply is used as the main power source in the microgrid for off-grid operation, the calculation of the active power deficit is of great significance for the frequency stability control of the microgrid. The method provided in this embodiment can quickly and accurately calculate the shortfall of the active power of the microgrid when the frequency is abnormal. According to the calculated active power deficit, the active power output by the rotating power supply and the active power of the load are adjusted accordingly, so as to stabilize the operation of the entire microgrid. This method improves the adjustment mode of the active power of the microgrid from qualitative adjustment to quantitative adjustment. Moreover, considering the influence of the switching of each active device (including rotating power supply and load) in the microgrid on the frequency fluctuation in the microgrid, the safety and stability of the frequency is considered.

System embodiment two:

Referring to FIG. 5 , this figure is a schematic diagram of Embodiment 2 of the calculation system for the active power deficit of the microgrid provided by the present invention.

The calculation system for the active power deficit of the microgrid provided in this embodiment further includes: a current active power acquisition unit 501 of the rotating power source and a current active power acquisition unit 502 of the load;

For rotating power sources and loads, active power can be calculated from their corresponding voltage and current.

The current active power obtaining unit 501 of the rotary power supply is used to obtain the current active power from the current output voltage and output current of each rotary power supply

The current active power obtaining unit 502 of the load is used to obtain the current active power of each load from the current voltage and current

The method and system provided by the above embodiments can quickly calculate the corresponding active power deficit when the frequency changes in the microgrid system, and then perform corresponding control according to the calculated active power deficit, so that the microgrid system can work in a stable manner. state.

The above descriptions are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person familiar with the art, without departing from the scope of the technical solution of the present invention, can use the methods and technical content disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent of equivalent change Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

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 frequency_Gi*And K_Lj*；

<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 K_GiA and K_Lj*By the formulaObtaining unit regulation power K of micro-grid_M(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 of_E+。

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 frequency_Gi*And K_Lj*；

<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 K_Gi*And K_Lj*By the formulaObtaining unit regulation power K of micro-grid_M(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 of_E+。

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