AU2022205251A1 - Method and system for controlling power quality of an intergrated energy park based on cps - Google Patents
Method and system for controlling power quality of an intergrated energy park based on cps Download PDFInfo
- Publication number
- AU2022205251A1 AU2022205251A1 AU2022205251A AU2022205251A AU2022205251A1 AU 2022205251 A1 AU2022205251 A1 AU 2022205251A1 AU 2022205251 A AU2022205251 A AU 2022205251A AU 2022205251 A AU2022205251 A AU 2022205251A AU 2022205251 A1 AU2022205251 A1 AU 2022205251A1
- Authority
- AU
- Australia
- Prior art keywords
- generation equipment
- power generation
- supply system
- power supply
- resonant frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000010248 power generation Methods 0.000 claims abstract description 110
- 238000012546 transfer Methods 0.000 claims description 7
- 230000004044 response Effects 0.000 claims description 4
- 238000004364 calculation method Methods 0.000 claims description 3
- 230000006870 function Effects 0.000 description 7
- 238000005259 measurement Methods 0.000 description 7
- 230000001052 transient effect Effects 0.000 description 6
- 238000004458 analytical method Methods 0.000 description 5
- 238000011217 control strategy Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 230000000737 periodic effect Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 102100023703 C-C motif chemokine 15 Human genes 0.000 description 1
- 101000978376 Homo sapiens C-C motif chemokine 15 Proteins 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000002847 impedance measurement Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000004807 localization Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000007781 pre-processing Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- 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
- H02J3/241—The oscillation concerning frequency
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/12—Arrangements for reducing harmonics from ac input or output
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/505—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
- H02M7/515—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/40—Arrangements for reducing harmonics
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The present application provides a method and system for controlling power quality of an integrated
energy park based on CPS. The method includes: detecting, under a condition that the power supply system
resonates, electrical information of a power supply system of the integrated energy park, and determining a
resonant frequency according to the electrical information of the power supply system detecting electrical
information of each independent power generation equipment in the power supply system, and calculating a
port impedance of each independent power generation equipment, and drawing a frequency domain
impedance curve of each independent power generation equipment; extracting the port impedance of each
independent power generation equipment at the resonant frequency in the frequency domain impedance
curve; determining a weight value of the port impedance of each independent power generation equipment
at the resonant frequency; calculating a difference between the weight of the port impedance of each
independent power generation equipment at the resonant frequency and a weight of the port impedance of
corresponding independent power generation equipment under a condition that the power supply system is
in a normal steady-state conditions; determining an independent power generation equipment with the
largest difference as the resonant source.
Description
[00011 The present application generally relates to a technical field of integrated energy control, and in
particular, to a method and system for controlling power quality of an integrated energy park based on CPS
(Cyber-Physical Systems).
[00021 The power quality problems in an integrated energy park based on CPS mainly include two aspects:
the steady-state power quality and the transient power quality. The problem of steady-state power quality is
that three-phase voltage unbalance, high-order harmonics and long-term voltage are too high or too low.
The problem of transient power quality includes voltage sag and transient power failure. The problem of
steady-state power quality in CPS Park is often caused by internal rectifying equipment and nonlinear load.
This type of equipment will introduce high-order harmonics, resulting in a reduction in the steady-state
power quality. The steady-state power quality can be improved by installing APF and other equipment. The
transient power quality steady state of CPS is usually caused by the system short circuit fault and the
switching of impulse load. For the park, some of the precision equipment is sensitive to voltage sag and
transient power outage. Traditionally, a mechanical switch is used to switch the power supply bus.
However, the action of the mechanical switch is slow, and it is easy to cause the outage time to exceed the
maximum that the equipment can withstand. Thus, the operation of the park is affected. Therefore, it is
necessary to develop new devices and technologies to ensure the quality of power supply in CPS Park. The
waveform distortion is caused by the non-linear relationship between the current flowing through the
nonlinear load and the voltage applied on it. The distortion is periodic. Any periodic or quasi-periodic
distortion can be denoted by Fourier series. The component with an integral multiple of the fundamental
frequency is called a harmonic. The component with an integral multiple of the non-fundamental frequency
is called fractional harmonic or interharmonic, and the interharmonic with a frequency lower than industrial
frequency is also called subharmonic.
[00031 The power supply mode of CPS park presents various forms, and the introduction of various new
energy sources can easily cause the typical power quality problems such as resonance, power fluctuation,
and etc.. Therefore, the power quality problem of CPS park needs to be identified quickly. When a
component of the power supply system has a continuous power fluctuation and the frequency of the
fluctuation is close to the natural resonance frequency of the system, it may cause large-scale fluctuations.
There are many possible reasons for the continuous power fluctuation, such as the error of the converter
parameter setting, the fault of the excitation system of the motor and the non-synchronous grid connection
of the doubly-fed wind turbine. An effective way to deal with this kind of resonance is to find the source of
disturbance when the resonance occurs. How to quickly and effectively identify the disturbance source
which is the key factor affecting the power quality of CPS Park and has become an urgent technical
problem to be solved.
[00041 The exemplary embodiments of the present application provide a method and system for controlling
power quality of an integrated energy park based on CPS, which can quickly and effectively identify the
disturbance source.
[00051 According to an exemplary embodiment of the present application, a method for controlling power
quality of an integrated energy park based on CPS is provided. The method includes: detecting, under a
condition that the power supply system resonates, electrical information of a power supply system of the
integrated energy park, and determining a resonant frequency according to the electrical information of the
power supply system detecting electrical information of each independent power generation equipment in
the power supply system, and calculating a port impedance of each independent power generation
equipment, and drawing a frequency domain impedance curve of each independent power generation
equipment; extracting the port impedance of each independent power generation equipment at the resonant
frequency in the frequency domain impedance curve; determining a weight value of the port impedance of
each independent power generation equipment at the resonant frequency, according to the port impedance
of each independent power generation equipment at the resonant frequency and the total impedance of
power generation equipment which belong to the same class as the independent power generation
equipment; calculating a difference between the weight of the port impedance of each independent power
generation equipment at the resonant frequency and a weight of the port impedance of corresponding
independent power generation equipment when the power supply system is in a normal steady-state
conditions; determining an independent power generation equipment with the largest difference as the
resonant source.
[00061 According to another exemplary embodiment of the present application, a system for controlling
power quality of an integrated energy park based on CPS is provided. The device includes: a resonant
frequency determination module configured to detect electrical information of a power supply system of
the integrated energy park, and determine a resonant frequency according to the electrical information of
the power supply system when the power supply system resonates; a port impedance calculation module
configured to detect electrical information of each independent power generation equipment in the power supply system, and calculate a port impedance of each independent power generation equipment, and draw a frequency domain impedance curve of each independent power generation equipment; an impedance weight determination module configured to extract the port impedance of each independent power generation equipment at the resonant frequency in the frequency domain impedance curve, and determine a weight value of the port impedance of each independent power generation equipment at the resonant frequency, according to the port impedance of each independent power generation equipment at the resonant frequency and the total impedance of power generation equipment which belong to the same class as the independent power generation equipment; a resonant source determination module configured to calculate a difference between the weight of the port impedance of each independent power generation equipment at the resonant frequency and a weight of the port impedance of corresponding independent power generation equipment when the power supply system is in a normal steady-state conditions, and determine an independent power generation equipment with the largest difference as the resonant source.
[00071 According to the method and system for controlling power quality of an integrated energy park
based on CPS in the exemplary embodiments of the present application, electrical information of a power
supply system of the integrated energy park is detected, and a resonant frequency is determined according
to the electrical information of the power supply system when the power supply system resonates. Then
electrical information of each independent power generation equipment in the power supply system is
detected, and a port impedance of each independent power generation equipment is calculated. Following,
the port impedance of each independent power generation equipment at the resonant frequency is extracted,
and a weight value of the port impedance of each independent power generation equipment at the resonant
frequency is determined. Thus, a difference between the weight of the port impedance of each independent
power generation equipment at the resonant frequency and a weight of the port impedance of corresponding
independent power generation equipment when the power supply system is in a normal steady-state
conditions can be calculated. At the last, an independent power generation equipment with the largest
difference as the resonant source can be determined, thereby identifying the disturbance source quickly and
effectively.
[00081 Additional aspects and/or advantages of the general concept of the present application will be set
forth in part in the following description, and other parts will be apparent from the description, or may be
learned by practice of the general concept of the present application.
[00091 The above and other objects and features of the exemplary embodiments of the present application
will become more apparent from the following description in conjunction with the accompanying drawings that exemplarily illustrate the embodiments, in which:
[00101 Fig. 1 illustrates a schematic representation of the equivalent model of the independent power
generation equipment in the method for controlling power quality of an integrated energy park based on
CPS according to an exemplary embodiment of the present application;
[00111 Fig. 2 illustrates a schematic representation of the equivalent model of a plurality of parallel power
generation equipment in the method for controlling power quality of an integrated energy park based on
CPS according to an exemplary embodiment of the present application;
[00121 Fig. 3 illustrates a flowchart of forced disturbance source location of a method for controlling power
quality of an integrated energy park based on CPS according to an exemplary embodiment of the present
application;
[00131 Fig. 4 illustrates a flowchart of a method for controlling power quality of an integrated energy park
based on CPS according to an exemplary embodiment of the present application;
[00141 Fig. 5 illustrates a simulation result diagram of the method for controlling power quality of an
integrated energy park based on CPS according to an exemplary embodiment of the present application;
[00151 Fig. 6 illustrates two-stage integrated multi-port AC/DC interconnection system according to an
exemplary embodiment of the present application;
[00161 Fig. 7 illustrates the three-phase current effective value waveform under the traditional control
method;
[00171 Fig. 8 illustrates a three-phase current RMS waveform of the method for controlling power quality
of an integrated energy park based on CPS according to an exemplary embodiment of the present
application;
[00181 Fig. 9 illustrates the comparison of the effects of various control methods;
[00191 Fig. 10 illustrates a structural block diagram of a system for controlling power quality of an
integrated energy park based on CPS according to an exemplary embodiment of the present application.
[00201 It is important to note that the various aspects of the implementation examples within the scope of
the attached claims are described below. It should be obvious that the aspects described in this article can be
reflected in a wide variety of forms, and that any particular structure and/or function described in this article
is only illustrative. Based on this disclosure, technical personnel in the field should be aware that an aspect
described in this article can be implemented independently of any other aspect, and that two or more of
these aspects can be combined in various ways. For example, any number of aspects described in this article
can be used to implement equipment and/or practices. In addition, the device and/or the method can be implemented and/or practiced using a structure and/or functionality other than one or more of the aspects described in this article.
[00211 The embodiments of the present application take the structure of a power generating device
connected in parallel with a PCC point as an example, under single-loop current control and double-loop
current control. The equivalent circuit model and s-domain mathematical model considering PWM
disturbance are derived, and the mechanism of multi-generation equipment causing resonance is analyzed.
The structure and equivalent circuit of the single-generation equipment are shown in Figure 1. Compared
with the traditional structure, the equivalent circuit adds the effect on the output current caused by voltage
disturbance Vdist in PWM process, and describes the DC bus voltage fluctuation, current disturbances
caused by power network harmonics in PWM link, and can be expressed as Equation (1).
[00221I2 = Grj(s)- I, -Y(s)±- Vcc + G,,,(s)- Vs, (1)
[00231 Based on the new equivalent circuit model, the equivalent model of multi-parallel generation
equipment is derived, as shown in Figure 2. Equation (2) is derived equivalent impedance matrix of the
same type of power generation equipment.
V 2o /edr1
[1 2 1 j [Y/edlj(S) 0 0e (S)) 12,2 __ 0 eeder 2(S) ---- 0 Y (S)
[00241 gri] (2) Yfeedr" (S)Yg,i (s) = te1, N] YS) +Ygrid (s)
[00251 Wherein i1( feeder,i(S) is the port admittance of a single
power generation equipment, the line admittance is feeder,(S) feeder,N(S). Each inverter is connected to
the PCC node via an LCL filter. Grid impedance is Lgri and Rgrid. Since power generation equipment uses
closed-loop current control, s-domain Noton equivalent model is used to describe each power generation
equipment. The whole system can be equivalent to N controlled current sources caused by reference
current, N controlled current sources caused by PWM disturbance voltage, and N parallel admittance
connected to PCC point in parallel. According to the model established above, the PCC point voltage Vpc
and a grid-connected current 12,1 of Inverter 1 can be deduced.
G 1 (s)- I + 1 GiI(s=)- Vis, + Ygrid (s)- Vgrid
[00261 V -- (s)+Y,id (s) (3)
10027112,1 = G,,'(s)r- I, '-Y(s)- Vcc + G (S) -Vis,,, (4)
[00281 Wherein G _ Gref, (s is a closed-loop transfer function of a controlled current source caused -ej(s)
by a reference current, Gd e,(s) - GdistN)isaclosed-looptransferfunctionofacontrolledcurrentcaused
by a reference current, I(S)- (s) is a parallel admittance, rid grid impedance,
rcef,N (S)is a current reference of a parallel inverter, dist,1(S) VdiN (S)is the PWM voltage disturbance of
the parallel inverter. The grid-connected current of Inverter 1 can be rewritten as follows. resonance caused by the PWM parallelresonance resonance caused by the PWM disturbancevoltage of other inverters internal resonance e - series resonance disturbancevoltage of the inverter N __N
[00291 2,1 = R,(s).re, + I (s) Irfi- S (S)*Vd+ D1(s). Vdstl + IK,(s)Vd,,tl (5) i=2 i=2
[0030 It can be seen that the equation (5) consists of three parts, each representing a resonant type. The first part internal resonance) refers to the resonance caused by the current reference of the inverter itself The second part (arallel resonance) refers to the resonance caused by the current reference of other
inverters. The third term (series resonance) represents the resonance induced by the power grid, which
reflects the series interaction between the power grid and the parallel inverter system. The fourth part
represents the resonance caused by the PWM disturbance voltage of the inverter itself, and the fifth part
represents the resonance caused by the PWM disturbance voltage of other inverters.
[00311 A method of disturbance source location descripted as follows. First, the spectrum of forced resonance signal and other random noise signal in the system is separated by bispectrum analysis, and the
central frequency of forced resonance is obtained. Then the phase information of the resonant center
frequency is obtained by wavelet transform, and the flow direction of the transient energy is calculated
based on the phase information.
[00321 B,(o,,co)2 -£1 2)2 (6) r,=- c2 =
[0033] Wherein C3x (1, T2) is the third-order cumulant of the signal. Bispectrum diagonal slice method is used to identify the center frequency of resonance. This method retains most of the signal characteristics
and the ability to suppress Gaussian noise, and has the advantages of intuitive and easy to calculate.
[00341 if CO - C2 =O, the diagonal slice of the bispectrum is defined as follows.
[0035] BxD() 1 2 ri=-c r2 =- o
100361 Because the bispectrum of the noise signal is almost zero, and the power fluctuation of the forced resonance is nonlinear, so the bispectrum can be used to separate it from the noise signal and extract the resonance center frequency.
[00371 Morlet wavelet is chosen as the base wavelet of analysis:
[00381
[00391 Let the central frequency of the resonance be oo, and let the wavelet parameters be chosen such that aN. - 0 = 0, in that the wavelet coefficients far away from the other components of the
central frequency of the resonance decay to 0 due to e2 , then the amplitude and phase information
near the resonant center frequency are extracted.
[00401 According to the analysis above, the method oflocating the disturbance source is shown in Figure 3.
The steps include:
[00411 Step 1: obtaining the power resonance signal in the region of forced resonance;
[00421 Step 2: pre-processing the power resonance signal to intercept the stable resonant signal;
[00431 Step 3: analyzing bispectrum of the stable resonant signal;
[00441 Step 4: obtaining the center frequency of forced resonance by bispectrum analysis;
[00451 Step 5: using wavelet transform to obtain the phase information of the frequency component of the
resonant signal;
[00461 Step 6: calculating the energy function flow direction of the system, and determining the location of
the forced resonance disturbance source, according to the phase information.
[00471 After the analysis of the above resonant source is extended to multi-machine system, the port
impedance curves of multi-power generation equipment of bus are calculated. The impedance curves are
compared and judged, which reflect the impedance factor of power generation equipment at this frequency,
and its essence is the direction of energy flow in a resonant period. In theory, the higher the negative
impedance near the resonant frequency of the interface converter, the higher the probability that the unit is
a resonant source, and the higher the resonant frequency at the same time section, the more obvious the
change of the system impedance curve, the larger the gap between resonant source and other non-resonant
source. The hierarchical identification strategy of multiple parallel generation units is obtained by using the
output line current 2,1 of a single generation unit through a Kirchhoffs circuit laws.
[00481 According to the above description, the location method of resonant source (power quality problem)
is given as shown in Figure 4.
[00491 Step 401: detecting, under a condition that the power supply system resonates, electrical information
of a power supply system of the integrated energy park, and determining a resonant frequency according to
the electrical information of the power supply system.
[0050] Step 402: detecting electrical information of each independent power generation equipment in the power supply system, and calculating a port impedance of each independent power generation equipment,
and drawing a frequency domain impedance curve of each independent power generation equipment.
[00511 Step 403: extracting the port impedance of each independent power generation equipment at the
resonant frequency in the frequency domain impedance curve; and determining a weight value of the port
impedance of each independent power generation equipment at the resonant frequency, according to the
port impedance of each independent power generation equipment at the resonant frequency and the total
impedance of power generation equipment which belong to the same class as the independent power
generation equipment. Step 404: calculating a difference between the weight of the port impedance of each
independent power generation equipment at the resonant frequency and a weight of the port impedance of
corresponding independent power generation equipment under a condition that the power supply system is
in a normal steady-state conditions; and determining an independent power generation equipment with the
largest difference as the resonant source.
[00521 Preferably, following step 404, also including: after determining the system resonant source as the Nth power generation equipment, provided that other controlled quantities do not mutate during the entire
measurement period, by measuring the port current several times and adding the small disturbance A re to
the current reference, the system can be operated in a wide-band harmonic winding or resonance frequency.
As shown in equation (9):
'Ila+ I'1 '(s)' ' S ---- P1() N rgJ+AIrg
[05+A2 Pn(s)' R2 (s)' Iref, 2 + ,2
[0053] .... .... .... .... ~ .... +K (9)
N+2 A2,N l(S)' PN 2 (s)' RN(S)' ref,N+Arf,N
D (s) K 12 (s) .... KlN(s) Vdi, Sg(s)
K2(Ss)ND2(s)jVdist,2 \Sg,2(s)j
LKN1(s) KN 2 (s) DN(s) VditN j Sg 2 (S))
[00551 Equation (9) describes the measurement results after adding small disturbances to the current
reference, in which K is the input quantity and the control parameter which need to be controlled to the
same state as the initial measurement, and there is no abrupt change during the measurement. The repeated
measurement obtains the current reference transfer coefficient and the corresponding converter transfer
function PIN (S)which is subtracted from N(S) of the
equation (10) to equation (11).
A NP2 1(s)-P(s)' R2 (s)-R2 (s)' P,(S)flNS)j AN,N
[0056] 1 1(S)-PN(S)' PN (S) PN2 (S)' RN(s)- R (10)
[0057] Take the maximum value of A, (x = 1,2,3...), take the maximum value Amax of
Ai, (i#j, i =3=j 1 ,2,3 --- , if there existsAmax 1.2 * ( iAi)/n and there exists x = i x =j , then power generation equipment x is the resonant source, if
Amax <1.2 *(>= 1 Aig)/n and Amax' 1.2 * (>j£ 1 1. Ai,)/n , it is considered that the
resonant source is the interaction of each power generation equipment to produce resonance, and the
resonant source can be defined as a power generation farm. If Amax 5 1.2 * (U ,=Ag)/n 7 and
max' 1.2 * (E1,U=jAi,)/n, then it is considered that the resonant source exists outside the
power generation farm, or the resonance caused by both the power generation farm and the power
grid.
( I2+2 'D ( Kl,(KD,,(' -- VKIit+AVs,1 I2,2 +A,, K'+ (S)' D2(S)' Vdist,2 Vdist,2
[0058] 12,+A 2,3 KN1(s)' KN 2 (s)' DN(S)' Vd,N+Adist,N 'R,(s) 1.2(s) ---- IM ) N-'ref,1')
K'= P(s) R2 (s) If2 S (s) -Vt
PN1(S) PN 2 (s) RN(S) ref,
[00591 dist,1 asthe input disturbance signal of measurement, it can represent the fluctuation of
DC voltage, the fluctuation component of converter modulation and so on. Because it is difficult to
introduce of wide-band, so a disturbance near the resonant frequency is introduced several times at the
operating point, measuring the output current response. Then, the transfer function of the corresponding
frequency power generation equipment is extracted.
[00601 A measurement model is used to simulate and verify the effectiveness of the impedance
measurement method for resonant source localization.
[00611 The direct-driven wind turbine or other new energy generation equipment is simplified as a
full-power converter at its port. The full-power inverter with LCL filter is simulated and verified. Filter
parameters denotes as L, = 2.5mHL2 =1mH , Cf = lp F. As shown in Figure 5, the following impedance
curves can be obtained by using the above port impedance measurement methods. It is obviously different from other converters at about 500Hz, and presents negative damping effect at resonant frequency, which proves the feasibility of this method.
[00621 The integrated multi-port AC/DC interconnection system is shown in Figure 6 in combination with
the power supply requirements of different sensitivity loads in the CPS park. The entire multi-port
interconnection equipment is divided into two stages. The former stage is connected to the 10kv AC
network by three-phase cascade H bridge, and the latter stage is connected in series and parallel by
multi-dual active bridge (DAB) modules. A plurality of DC ports with different voltage levels are formed
by the series-parallel connection of a plurality of DAB modules at the DC output side while the isolation is
carried out.
[00631 Base on this topology, 10kv AC network can supply direct power to DC load of different voltage
levels in CPS Park by only two-stage converter, and the overall power supply efficiency is greatly
improved.
[00641 However, due to the complex power coupling between multi-ports, it is the base of equipment
application to control the system reasonably and ensure its stable and reliable operation under various
working conditions. Based on the problem of unsymmetrical grid-connected current and unbalance of
capacitor voltage caused by voltage sag, the integrated operation control strategy based on zero sequence
voltage injection and secondary capacitor voltage balance control is proposed. The stable and reliable
operation of the integrated equipment under various typical working conditions is well guaranteed.
Simulation and experimental results demonstrate the effectiveness of the proposed strategy.
[00651 Through zero-sequence voltage injection and secondary voltage equalization control, integrated
multi-port devices can ensure stable and reliable operation when voltage sags and load fluctuations occur,
as shown in figure 7 to figure 9.
[00661 As can be seen from the figure above, when using the traditional control method, when the output
port load changes suddenly, the three-phase grid-connected current appears unbalanced, which will lead to
the whole system off-grid risk. The proposed control strategy can ensure the symmetry of three-phase
grid-connected current even if the three-phase load is unbalanced. In addition, when voltage sags occur, the
traditional control strategy will lose the balance control of capacitor voltage, which will lead to DC voltage
fluctuation. When the proposed control strategy is adopted, the stable and reliable operation of the system
can be ensured even when the voltage sags in the power grid.
[00671 Fig. 10 is a structural block diagram of a system for controlling power quality of an integrated
energy park based on CPS according to an exemplary embodiment of the present application. The
embodiment shown in figure 1-figure 9 may be used to interpret this embodiment. As shown in Figure 10, a
system for controlling power quality of an integrated energy park based on CPS, wherein the system, including:
[00681 A resonant frequency determination module 1001 is configured to detect, under a condition that the
power supply system resonates, electrical information of a power supply system of the integrated energy
park, and determine a resonant frequency according to the electrical information of the power supply
system.
[00691 A port impedance calculation module 1002 is configured to detect electrical information of each
independent power generation equipment in the power supply system, and calculate a port impedance of
each independent power generation equipment, and draw a frequency domain impedance curve of each
independent power generation equipment.
[00701 An impedance weight determination module 1003 is configured to extract the port impedance of
each independent power generation equipment at the resonant frequency in the frequency domain
impedance curve, and determine a weight value of the port impedance of each independent power
generation equipment at the resonant frequency according to the port impedance of each independent
power generation equipment at the resonant frequency and the total impedance of power generation
equipment which belong to the same class as the independent power generation equipment.
[00711 A resonant source determination module 1004 is configured to calculate a difference between the
weight of the port impedance of each independent power generation equipment at the resonant frequency
and a weight of the port impedance of corresponding independent power generation equipment under a
condition that the power supply system is in a normal steady-state conditions, and
determine an independent power generation equipment with the largest difference as the resonant source.
[00721 Preferably, the resonant frequency determination module 1001 is configured to detect, under a
condition that the power supply system resonates, port voltage and current of the power supply system, and
analyze the amplitude and phase information of the port voltage and current of the power supply system
based on DFT to determine the resonant frequency, wherein the electrical information includes the port
voltage and current of the power supply system.
[00731 Preferably, the impedance weight determination module 1003 is configured to calculate a ratio of
the port impedance of each independent power generation equipment at the resonant frequency to the total
impedance of power generation equipment which belong to the same class as the independent power
generation equipment, and determine the ratio as the weight value of the port impedance of each
independent power generation equipment at the resonant frequency.
[00741 Preferably the resonant source determination module 1004 is configured to add a harmonic
disturbance at the resonant frequency to the power supply system several times to detect an output current
response of the power supply system, and then extract a transfer function of power generation equipment in the power supply system, and determine a resonance of the resonant source is caused by the power supply system orjointly by the power supply system and a power grid.
[00751 Preferably, the power supply system includes an AC-DC connection system, the AC-DC connection
system includes a first-stage structure and a second-stage structure connected with the first-stage structure.
The first-stage structure includes a three-phase cascade H bridge. The second stage structure includes a
plurality of DAB modules. The first stage structure is connected with a 10kv AC power grid; one side of the
plurality of DAB modules in the second stage structure is connected in series and is connected with the first
stage structure. The another side of the plurality of DAB modules is connected in parallel to form a plurality
of DC ports of different voltage grades, and the plurality of DC ports of different voltage grades are
connected with DC loads of different voltage grades in the integrated energy park based on CPS.
[00761 The embodiment has the corresponding technical effect of the method for controlling power quality
of an integrated energy park based on CPS, and shall not be repeated here.
[00771 The present application also provides a computer readable medium on which a computer instruction
is stored. When the computer instruction is executed by a processor, the processor is made to perform the
method for controlling power quality of an integrated energy park based on CPS.
[00781 In this case, the program code read from the storage medium itself may perform the function of any
of the embodiments, so that the program code and the storage medium in which the stored program code is
stored form part of the present application.
[00791 Storage media embodiments for providing program code include floppy disks, hard disks,
magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM,
DVD-RW, DVD + RW), magnetic tapes, nonvolatile memory cards, and ROMs. Optionally program code
can be downloaded from the server computer by the communication network.
[00801 While a few exemplary embodiments of the present application have been shown and described,
those skilled in the art will appreciate that modifications can be made to these embodiments without
departing from the principle and spirit of the present application whose scope is limited by the claims and
their equivalents.
Claims (10)
1. A method for controlling power quality of an integrated energy park based on CPS, wherein the
method comprises:
detecting, under a condition that the power supply system resonates, electrical information of a power
supply system of the integrated energy park, and determining a resonant frequency according to the
electrical information of the power supply system;
detecting electrical information of each independent power generation equipment in the power supply
system, and calculating a port impedance of each independent power generation equipment, and drawing a
frequency domain impedance curve of each independent power generation equipment;
extracting the port impedance of each independent power generation equipment at the resonant
frequency in the frequency domain impedance curve;
determining a weight value of the port impedance of each independent power generation equipment at
the resonant frequency, according to the port impedance of each independent power generation equipment
at the resonant frequency and the total impedance of power generation equipment which belong to the same
class as the independent power generation equipment;
calculating a difference between the weight of the port impedance of each independent power
generation equipment at the resonant frequency and a weight of the port impedance of corresponding
independent power generation equipment under a condition that the power supply system is in a normal
steady-state conditions;
determining an independent power generation equipment with the largest difference as the resonant
source.
2. The method according to claim 1, wherein the step of detecting, under a condition that the power
supply system resonates, electrical information of a power supply system of the integrated energy park, and
determining a resonant frequency according to the electrical information of the power supply system
comprises:
detecting port voltage and current of the power supply system under a condition that the power supply system resonates;
analyzing the amplitude and phase information of the port voltage and current of the power supply
system based on DFT to determine the resonant frequency; the electrical information includes the port voltage and current of the power supply system.
3. The method according to claim 2, wherein the step of determining a weight value of the port
impedance of each independent power generation equipment at the resonant frequency, according to the
port impedance of each independent power generation equipment at the resonant frequency and the total
impedance of power generation equipment which belong to the same class as the independent power
generation equipment comprises:
calculating a ratio of the port impedance of each independent power generation equipment at the
resonant frequency to the total impedance of power generation equipment which belong to the same class as
the independent power generation equipment;
determining the ratio as the weight value of the port impedance of each independent power generation
equipment at the resonant frequency.
4. The method according to claim 3, wherein after the step of determining an independent power
generation equipment with the largest difference as the resonant source, further comprises:
adding a harmonic disturbance at the resonant frequency to the power supply system several times to
detect an output current response of the power supply system, and then extracting a transfer function of
power generation equipment in the power supply system;
determining a resonance of the resonant source is caused by the power supply system or jointly by the
power supply system and a power grid.
5. The method according to claim 4, wherein the power supply system comprises an AC-DC
connection system, the AC-DC connection system comprises a first-stage structure and a second-stage
structure connected with the first-stage structure;
the first-stage structure comprises a three-phase cascade H bridge, the second stage structure
comprises a plurality of DAB modules;
the first stage structure is connected with a 10kv AC power grid; one side of the plurality of DAB
modules in the second stage structure is connected in series and is connected with the first stage structure;
the another side of the plurality of DAB modules is connected in parallel to form a plurality of DC ports of
different voltage grades, and the plurality of DC ports of different voltage grades are
connected with DC loads of different voltage grades in the integrated energy park based on CPS.
6. A system for controlling power quality of an integrated energy park based on CPS, wherein the system comprises: a resonant frequency determination module configured to detect, under a condition that the power supply system resonates, electrical information of a power supply system of the integrated energy park, and determine a resonant frequency according to the electrical information of the power supply system; a port impedance calculation module configured to detect electrical information of each independent power generation equipment in the power supply system, and calculate a port impedance of each independent power generation equipment, and draw a frequency domain impedance curve of each independent power generation equipment; an impedance weight determination module configured to extract the port impedance of each independent power generation equipment at the resonant frequency in the frequency domain impedance curve, and determine a weight value of the port impedance of each independent power generation equipment at the resonant frequency, according to the port impedance of each independent power generation equipment at the resonant frequency and the total impedance of power generation equipment which belong to the same class as the independent power generation equipment; a resonant source determination module configured to calculate a difference between the weight of the port impedance of each independent power generation equipment at the resonant frequency and a weight of the port impedance of corresponding independent power generation equipment under a condition that the power supply system is in a normal steady-state conditions, and determine an independent power generation equipment with the largest difference as the resonant source.
7. The system according to claim 6, wherein the resonant frequency determination module is
configured to detect, under a condition that the power supply system resonates, port voltage and current of
the power supply system, and analyze the amplitude and phase information of the port voltage and current
of the power supply system based on DFT to determine the resonant frequency, wherein the electrical
information includes the port voltage and current of the power supply system.
8. The system according to claim 7, wherein the impedance weight determination module is
configured to calculate a ratio of the port impedance of each independent power generation equipment at
the resonant frequency to the total impedance of power generation equipment which belong to the same
class as the independent power generation equipment, and determine the ratio as the weight value of the
port impedance of each independent power generation equipment at the resonant frequency.
9. The system according to claim 8, wherein the resonant source determination module is configured to add a harmonic disturbance at the resonant frequency to the power supply system several times to detect an output current response of the power supply system, and then extract a transfer function of power generation equipment in the power supply system, and determine a resonance of the resonant source is caused by the power supply system or jointly by the power supply system and a power grid.
10. The system according to claim 9, wherein the power supply system comprises an AC-DC
connection system, the AC-DC connection system comprises a first-stage structure and a second-stage
structure connected with the first-stage structure;
the first-stage structure comprises a three-phase cascade H bridge, the second stage structure
comprises a plurality of DAB modules;
the first stage structure is connected with a 10kv AC power grid; one side of the plurality of DAB
modules in the second stage structure is connected in series and is connected with the first stage structure;
the another side of the plurality of DAB modules is connected in parallel to form a plurality of DC ports of
different voltage grades, and the plurality of DC ports of different voltage grades are connected with DC
loads of different voltage grades in the integrated energy park based on CPS.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210605534.1A CN115498652B (en) | 2022-05-30 | 2022-05-30 | CPS-based comprehensive energy park electric energy quality control method and system |
| CN202210605534.1 | 2022-05-30 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU2022205251A1 true AU2022205251A1 (en) | 2023-12-14 |
| AU2022205251B2 AU2022205251B2 (en) | 2024-04-04 |
Family
ID=84464242
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2022205251A Active AU2022205251B2 (en) | 2022-05-30 | 2022-07-14 | Method and system for controlling power quality of an intergrated energy park based on cps |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN115498652B (en) |
| AU (1) | AU2022205251B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109830972A (en) * | 2019-02-15 | 2019-05-31 | 湖南大学 | A kind of new energy station oscillation source system for rapidly identifying and method |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102545245B (en) * | 2012-01-16 | 2013-12-04 | 清华大学 | Method for positioning oscillating source of power system on basis of energy supplied to port |
| RU2521768C2 (en) * | 2012-07-20 | 2014-07-10 | Открытое Акционерное Общество "Системный Оператор Единой Энергетической Системы" | Method for determination of synchronous oscillations source |
| WO2016138750A1 (en) * | 2015-03-04 | 2016-09-09 | 江苏省电力公司常州供电公司 | Power quality disturbance source locating system and locating method |
| CN105119286B (en) * | 2015-10-08 | 2017-05-17 | 南京南瑞继保电气有限公司 | Subsynchronous oscillation source location method and apparatus |
| CN106058897B (en) * | 2016-07-28 | 2018-09-21 | 东南大学 | A kind of generator Forced disturbance source localization method based on phasor |
| CN106340889B (en) * | 2016-10-11 | 2018-10-23 | 河海大学 | Based on the oscillation examination and disturbance source locating method for playing vibration analysis |
| CN110417056B (en) * | 2019-07-30 | 2020-12-18 | 华北电力大学 | Equipment-level oscillation source positioning method and device of doubly-fed fan grid-connected system |
| CN110425092B (en) * | 2019-07-30 | 2020-06-16 | 华北电力大学 | Wind power grid-connected system oscillation source positioning system and method based on energy spectrum |
| US11340271B2 (en) * | 2020-07-31 | 2022-05-24 | University Of Tennessee Research Foundation | Forced oscillation source location determination based on oscillation mode angle analysis using synchrophasor data |
| CN112018784B (en) * | 2020-08-28 | 2022-01-11 | 四川大学 | Subsynchronous resonance tracing method based on synchronous phasor measurement data |
-
2022
- 2022-05-30 CN CN202210605534.1A patent/CN115498652B/en active Active
- 2022-07-14 AU AU2022205251A patent/AU2022205251B2/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109830972A (en) * | 2019-02-15 | 2019-05-31 | 湖南大学 | A kind of new energy station oscillation source system for rapidly identifying and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115498652B (en) | 2024-04-30 |
| AU2022205251B2 (en) | 2024-04-04 |
| CN115498652A (en) | 2022-12-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108490288B (en) | A kind of stealing detection method and system | |
| Timbus et al. | Online grid measurement and ENS detection for PV inverter running on highly inductive grid | |
| AU2013201595B2 (en) | Method and apparatus for harmonic state estimation in power system | |
| Jang et al. | Development of a logical rule-based islanding detection method for distributed resources | |
| Hagh et al. | Multisignal histogram‐based islanding detection using neuro‐fuzzy algorithm | |
| Moreira et al. | Intelligent expert system for power quality improvement under distorted and unbalanced conditions in three-phase AC microgrids | |
| Zhang et al. | Study of resonance issues between DFIG-based offshore wind farm and HVDC transmission | |
| CN109993665B (en) | Online safety and stability assessment method, device and system for power system | |
| Nair et al. | Power quality analysis for building integrated PV and micro wind turbine in New Zealand | |
| Todeschini et al. | Time-domain modeling of a distribution system to predict harmonic interaction between PV converters | |
| Alghamdi et al. | An artificial neural network based harmonic distortions estimator for grid-connected power converter-based applications | |
| Alhussainy et al. | Power quality analysis of a large grid-tied solar photovoltaic system | |
| Taghvaie et al. | A comprehensive review of harmonic issues and estimation techniques in power system networks based on traditional and artificial intelligence/machine learning | |
| CN113852120A (en) | Method and system for determining maximum grid-connected capacity of new energy power generation | |
| AU2022205251A1 (en) | Method and system for controlling power quality of an intergrated energy park based on cps | |
| CN106849070B (en) | Multiple-variable flow device resonance unstability responsibility appraisal procedure arranged side by side at weak grid PCC | |
| CN112436542A (en) | Steady-state safety emergency control online pre-decision method considering stability control strategy | |
| Boukadoum et al. | Faults Diagnosis of Active Power Filter Using Fuzzy Logic Controller under Different Conditions | |
| Long et al. | Data-driven hybrid equivalent dynamic modeling of multiple photovoltaic power stations based on ensemble gated recurrent unit | |
| Madani et al. | Data-driven passivity-based current controller design for power-electronic converters of traction systems | |
| Nobile et al. | Distributed converters in large PV plants: performance analysis supported by behavioral models | |
| Depla | Harmonic interactions in HVAC-connected offshore windfarms | |
| Castelo et al. | Power Quality and Hosting Capacity in Islanding Microgrids | |
| Gumilar et al. | Implementation of FCL in Hybrid AC/DC Distribution Network System | |
| CN105824980B (en) | A kind of more level UPQC topological structure appraisal procedures |