CN103580025A - Adaptive filtering method for resonant frequency iteration transfer based on modal frequency sensitivity - Google Patents

Abstract

Provided is an adaptive filtering method for resonant frequency iteration transfer based on modal frequency sensitivity. The adaptive filtering method for resonant frequency iteration transfer based on the modal frequency sensitivity comprises the steps that the resonant frequency of a power system comprising an adaptive filter is detected by using a modal analytical method according to the structure of the power system, the modal frequency sensitivity of an inductor and the modal frequency sensitivity of a capacitor of the adaptive filter are determined through calculated structural parameters of the power system and parameters of the adaptive filter, repeated iterative computation is carried out by using the inductance with high modal frequency sensitivity or the capacitance with high modal frequency sensitivity as the input value, and using the resonant frequency as the output value, and the capacitance and the inductance of the adaptive filter are computed in an iteration mode when the resonant frequency of the power system is the even number of times of the power frequency or is close to the even number of times of the power frequency. Therefore, it is ensured that the adaptive filter can filter odd harmonic, the parameters of the adaptive filter are adjusted adaptively according to changes of the operating state of the power system, the resonant frequency of the power system can keep away from the odd harmonic frequency, harmonic resonance is effectively avoided, and power supply quality and safety of the power system can be better ensured.

Description

The adaptive filter method that resonance frequency iteration based on model frequency susceptibility shifts

Technical field

The present invention relates to harmonic resonance improvement sef-adapting filter in a kind of power industry.

Technical background

Along with coming into operation of increasing non-linear equipment, the odd harmonics such as can produce in electric power system a large amount of 3,5,7,9,11, these harmonic waves make the Efficiency Decreasing of transmission and the utilization of electric energy, make device of overheating of electrical, produce vibration and noise, and make ageing of insulation, shorten useful life, even breaks down or burn.And if these humorous wave frequencies are as identical with the resonance frequency of electric power system, can cause the resonance of electric power system, harmonic content is amplified, cause the serious distortion of harmonic wave, the running environment of severe exacerbation electric power system.

The main method of harmonic wave control is to adopt LC tuned filter, filters out 3,5,7,9,11 odd harmonics a large amount of in electric power system, to reduce Harmfulness Caused by Harmonics.But because the parameter of LC tuned filter is fixed, and the state that puts into operation of non-linear equipment changes at any time in electric power system, comprising filter also changes at any time in the resonance frequency of interior electric power system, make resonance frequency be difficult to avoid identical with odd harmonic frequencies, cause system generation resonance, harmonic wave amplifies, and LC filter overload is even burnt.

Summary of the invention

The object of the invention is to propose the adaptive filter method that a kind of resonance frequency iteration based on model frequency susceptibility shifts, the method can well filter out the odd harmonic of electric power system, the resonance frequency of adjustment electric power system that simultaneously can be dynamic, real-time, avoid electric power system generation harmonic resonance, better guarantee power supply quality and the safe and stable operation of electric power system.

The present invention realizes its goal of the invention, and the technical scheme adopting is: the adaptive filter method that a kind of resonance frequency iteration based on model frequency susceptibility shifts, the steps include:

A, processor are according to inductance initial value, the electric capacity initial value of the sef-adapting filter of input, the topological structure of the electric power system of input and equivalent inductance, equivalent capacity, the equivalent resistance of the electric power system calculated are calculated the original resonance frequency of electric power system, if 3,5,7,9 or 11 overtones bands of the original resonance frequency drawing and power frequency poor≤25Hz carries out the operation that b walks; Otherwise processor, by the inductance initial value of sef-adapting filter, corresponding inductance end value, the electric capacity end value of being defined as of electric capacity initial value, is carried out the operation of d step;

B, processor are according to inductance initial value, the electric capacity initial value of the sef-adapting filter of input, equivalent inductance, equivalent capacity, the equivalent resistance of the topological structure of the electric power system of input and the electric power system of calculating, calculate the model frequency susceptibility of electric capacity in sef-adapting filter, the model frequency susceptibility of inductance, as the model frequency susceptibility of electric capacity, take more greatly electric capacity and carry out the iterative computation of resonance frequency as iteration input value, otherwise the inductance of take carries out the iterative computation of resonance frequency as iteration input value; When the resonance frequency that iterative computation goes out is the even-multiple of power frequency, corresponding capacitance or inductance value are definite revision capacitance or revision inductance value, the frequency filtering of setting according to sef-adapting filter again calculates calculating inductance value corresponding to revision capacitance, or the frequency filtering of setting according to sef-adapting filter calculates calculating capacitance corresponding to revision inductance value;

C, processor are according to revision capacitance and calculating inductance value or revision inductance value and calculating capacitance, and equivalent inductance, equivalent capacity, the equivalent resistance of the topological structure of the electric power system of input and the electric power system of calculating are calculated the revision resonance frequency of electric power system;

If 3,5,7,9 or 11 overtones bands of the revision resonance frequency drawing and power frequency poor≤25Hz,, using revising capacitance and calculating inductance value or revision inductance value and inductance initial value, the electric capacity initial value of calculating capacitance as sef-adapting filter, re-execute the operation of b step;

Otherwise processor is by revision capacitance and calculating inductance value or revision inductance value and calculate inductance end value, the electric capacity end value that capacitance is defined as sef-adapting filter, carries out the operation that d walks;

D, the corresponding capacitor of processor control switch matrix switching and inductor, the total capacitance value of switching equals final capacitance, and the total inductance value of switching equals final inductance value.

Compared with prior art, the invention has the beneficial effects as follows:

First according to NETWORK STRUCTURE PRESERVING POWER SYSTEM, utilize modal analysis method to detect to comprise the electric power system resonance frequency of sef-adapting filter, then utilize the NETWORK STRUCTURE PRESERVING POWER SYSTEM parameter calculate and sef-adapting filter parameter to determine the model frequency susceptibility of inductance and electric capacity in sef-adapting filter, and using the large inductance of model frequency susceptibility or electric capacity as input value, take resonance frequency as the output valve calculating that iterates, capacitance and the inductance value of the even-multiple that the resonance frequency of iteration calculation system is power frequency or near the sef-adapting filter it time.Thereby when guaranteeing that filter can filter out the odd harmonic of electric power system, dynamic according to the variation of operation states of electric power system, self adaptation regulates the parameter of filter, to adjust the resonance frequency of electric power system, make it away from a large amount of odd harmonics that occur in electric power system, effectively avoid electric power system generation harmonic resonance, better guarantee power supply quality and the safe and stable operation of electric power system.

Due in the interative computation of resonance frequency, choose the element that Modal sensitivity is large (inductance, electric capacity) and carry out interative computation as input value, so its interative computation fast convergence rate, iterations is few, computation complexity is low, real-time is good.

In described b step, processor is calculated the model frequency susceptibility of electric capacity in sef-adapting filter, the specific practice of the model frequency susceptibility of inductance is according to equivalent inductance, equivalent capacity, the equivalent resistance of inductance initial value, electric capacity initial value and the NETWORK STRUCTURE PRESERVING POWER SYSTEM of the sef-adapting filter of input:

In sef-adapting filter, the model frequency susceptibility of electric capacity is

$\frac{\mathrm{df}}{\mathrm{dC}}=-\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{\∂f\∂C}\right)/\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{{\∂f}^2}\right)$

In formula, f is original resonance frequency, and C is the electric capacity initial value in sef-adapting filter, λ _mfor the inverse of the equivalent inductance of NETWORK STRUCTURE PRESERVING POWER SYSTEM, equivalent capacity, equivalent resistance sum,

for derivative operation, for secondary derivative operation.

In sef-adapting filter, the model frequency susceptibility of inductance is

$\frac{\mathrm{df}}{\mathrm{dL}}=-\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{\∂f\∂L}\right)/\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{{\∂f}^2}\right)$

In formula, f is original resonance frequency, and L is the inductance initial value in sef-adapting filter, λ _mfor the inverse of the equivalent inductance of NETWORK STRUCTURE PRESERVING POWER SYSTEM, equivalent capacity, equivalent resistance sum, for derivative operation,

for secondary derivative operation.

Like this by resonance frequency to the derivative of electric capacity or inductance the model frequency susceptibility as electric capacity or inductance, it calculates simple, also can well react the influence degree of the variation of electric capacity or inductance to resonance frequency simultaneously.

The electric capacity of take in described b step carries out the iterative computation of resonance frequency as iteration input value, or take inductance and as the iterative formula that transformed value carries out the iterative computation of resonance frequency be:

$a^{(k+1)}=a^{\left(k\right)}[1+h^{\left(k\right)}/J^{\left(k\right)}]=a^{\left(k\right)}[1+(f^{\left(k\right)}-f_0)/\frac{{\∂f}^{\left(k\right)}}{{\∂\mathrm{\α}}^{\left(k\right)}}]$

A in formula ^(k)be capacitance or the inductance value that the k time iteration goes out, a ^(k+1)be capacitance or the inductance value that the k+1 time iteration goes out, f ^(k)be the resonant frequency value that the k time iteration goes out, f ₀for with f ^(k)the even-multiple frequency of immediate power frequency.

By this operation method, can calculate simply, fast even-multiple that iteration resonance frequency is power frequency or capacitance and the inductance value of near the sef-adapting filter it time.

embodiment

Embodiment

A kind of embodiment of the present invention is that the adaptive filter method that a kind of resonance frequency iteration based on model frequency susceptibility shifts, the steps include:

A, processor are according to inductance initial value, the electric capacity initial value of the sef-adapting filter of input, the topological structure of the electric power system of input and equivalent inductance, equivalent capacity, the equivalent resistance of the electric power system calculated are calculated the original resonance frequency of electric power system, if 3,5,7,9 or 11 overtones bands of the original resonance frequency drawing and power frequency poor≤25Hz carries out the operation that b walks; Otherwise processor, by the inductance initial value of sef-adapting filter, corresponding inductance end value, the electric capacity end value of being defined as of electric capacity initial value, is carried out the operation of d step;

B, processor are according to inductance initial value, the electric capacity initial value of the sef-adapting filter of input, equivalent inductance, equivalent capacity, the equivalent resistance of the topological structure of the electric power system of input and the electric power system of calculating, calculate the model frequency susceptibility of electric capacity in sef-adapting filter, the model frequency susceptibility of inductance.

Processor is calculated the model frequency susceptibility of electric capacity in sef-adapting filter, the specific practice of the model frequency susceptibility of inductance is according to equivalent inductance, equivalent capacity, the equivalent resistance of inductance initial value, electric capacity initial value and the NETWORK STRUCTURE PRESERVING POWER SYSTEM of the sef-adapting filter of input:

In sef-adapting filter, the model frequency susceptibility of electric capacity is

$\frac{\mathrm{df}}{\mathrm{dC}}=-\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{\∂f\∂C}\right)/\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{{\∂f}^2}\right)$

In formula, f is original resonance frequency, and C is the electric capacity initial value in sef-adapting filter, λ _mfor the inverse of the equivalent inductance of NETWORK STRUCTURE PRESERVING POWER SYSTEM, equivalent capacity, equivalent resistance sum,

for derivative operation,

for secondary derivative operation.

In sef-adapting filter, the model frequency susceptibility of inductance is

$\frac{\mathrm{df}}{\mathrm{dL}}=-\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{\∂f\∂L}\right)/\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{{\∂f}^2}\right)$

In formula, f is original resonance frequency, and L is the inductance initial value in sef-adapting filter, λ _mfor the inverse of the equivalent inductance of NETWORK STRUCTURE PRESERVING POWER SYSTEM, equivalent capacity, equivalent resistance sum,

for derivative operation,

for secondary derivative operation.

As the model frequency susceptibility of electric capacity, take more greatly electric capacity and carry out the iterative computation of resonance frequency as iteration input value, otherwise the inductance of take carries out the iterative computation of resonance frequency as iteration input value; When the resonance frequency that iterative computation goes out is the even-multiple of power frequency, corresponding capacitance or inductance value are definite revision capacitance or revision inductance value, the frequency filtering of setting according to sef-adapting filter again calculates calculating inductance value corresponding to revision capacitance, or the frequency filtering of setting according to sef-adapting filter calculates calculating capacitance corresponding to revision inductance value.

The electric capacity of take carries out the iterative computation of resonance frequency as iteration input value, or take inductance and as the iterative formula that transformed value carries out the iterative computation of resonance frequency be:

$a^{(k+1)}=a^{\left(k\right)}[1+h^{\left(k\right)}/J^{\left(k\right)}]=a^{\left(k\right)}[1+(f^{\left(k\right)}-f_0)/\frac{{\∂f}^{\left(k\right)}}{{\∂\mathrm{\α}}^{\left(k\right)}}]$

A in formula ^(k)be capacitance or the inductance value that the k time iteration goes out, a ^(k+1)be capacitance or the inductance value that the k+1 time iteration goes out, f ^(k)be the resonant frequency value that the k time iteration goes out, f ₀for with f ^(k)the even-multiple frequency of immediate power frequency.

C, processor are according to revision capacitance and calculating inductance value or revision inductance value and calculating capacitance, and equivalent inductance, equivalent capacity, the equivalent resistance of the topological structure of the electric power system of input and the electric power system of calculating are calculated the revision resonance frequency of electric power system;

If 3,5,7,9 or 11 overtones bands of the revision resonance frequency drawing and power frequency poor≤25Hz,, using revising capacitance and calculating inductance value or revision inductance value and inductance initial value, the electric capacity initial value of calculating capacitance as sef-adapting filter, re-execute the operation of b step;

Otherwise processor is by revision capacitance and calculating inductance value or revision inductance value and calculate inductance end value, the electric capacity end value that capacitance is defined as sef-adapting filter, carries out the operation that d walks;

D, the corresponding capacitor of processor control switch matrix switching and inductor, the total capacitance value of switching equals final capacitance, and the total inductance value of switching equals final inductance value.

The computational methods of original resonance frequency f in the present invention are prior art.As adopted following methods to calculate:

According to Modal Analysis Theory, there is following equation:

$V_F=Y_F^{-1}{I}_F$

In formula, Y _ffor the system node admittance at frequency F place (inverse of impedance) matrix; V _f, I _fbe respectively node voltage, Injection Current vector.

By system node admittance matrix Y _fcarry out Diagonalization Decomposition, obtain diagonal angle eigenvalue matrix Λ, that is:

Y _F=lΛt，Λ=diag(λ ₁,λ ₂,L,λ _k)，

In formula, k is system node number; L, t is respectively left and right eigenvectors matrix, and l=t ^-1, diag represents diagonal matrix.When diagonal angle eigenvalue matrix Λ levels off to, (have the node that node voltage is very high to exist) when unusual, corresponding frequency F is original resonance frequency f.

Claims (3)

1. the adaptive filter method that the resonance frequency iteration based on model frequency susceptibility shifts, the steps include:

A, processor are according to inductance initial value, the electric capacity initial value of the sef-adapting filter of input, the topological structure of the electric power system of input and equivalent inductance, equivalent capacity, the equivalent resistance of the electric power system calculated are calculated the original resonance frequency of electric power system, if 3,5,7,9 or 11 overtones bands of the original resonance frequency drawing and power frequency poor≤25Hz carries out the operation that b walks; Otherwise processor, by the inductance initial value of sef-adapting filter, corresponding inductance end value, the electric capacity end value of being defined as of electric capacity initial value, is carried out the operation of d step;

B, processor are according to inductance initial value, the electric capacity initial value of the sef-adapting filter of input, equivalent inductance, equivalent capacity, the equivalent resistance of the topological structure of the electric power system of input and the electric power system of calculating, calculate the model frequency susceptibility of electric capacity in sef-adapting filter, the model frequency susceptibility of inductance, as the model frequency susceptibility of electric capacity, take more greatly electric capacity and carry out the iterative computation of resonance frequency as iteration input value, otherwise the inductance of take carries out the iterative computation of resonance frequency as iteration input value; When the resonance frequency that iterative computation goes out is the even-multiple of power frequency, corresponding capacitance or inductance value are definite revision capacitance or revision inductance value, the frequency filtering of setting according to sef-adapting filter again calculates calculating inductance value corresponding to revision capacitance, or the frequency filtering of setting according to sef-adapting filter calculates calculating capacitance corresponding to revision inductance value;

C, processor are according to revision capacitance and calculating inductance value or revision inductance value and calculating capacitance, and equivalent inductance, equivalent capacity, the equivalent resistance of the topological structure of the electric power system of input and the electric power system of calculating are calculated the revision resonance frequency of electric power system;

If 3,5,7,9 or 11 overtones bands of the revision resonance frequency drawing and power frequency poor≤25Hz,, using revising capacitance and calculating inductance value or revision inductance value and inductance initial value, the electric capacity initial value of calculating capacitance as sef-adapting filter, re-execute the operation of b step;

Otherwise processor is by revision capacitance and calculating inductance value or revision inductance value and calculate inductance end value, the electric capacity end value that capacitance is defined as sef-adapting filter, carries out the operation that d walks;

D, the corresponding capacitor of processor control switch matrix switching and inductor, the total capacitance value of switching equals final capacitance, and the total inductance value of switching equals final inductance value.

2. a kind of adaptive filter method according to claim 1, it is characterized in that: in described b step, processor is calculated the model frequency susceptibility of electric capacity in sef-adapting filter, the specific practice of the model frequency susceptibility of inductance is according to equivalent inductance, equivalent capacity, the equivalent resistance of inductance initial value, electric capacity initial value and the NETWORK STRUCTURE PRESERVING POWER SYSTEM of the sef-adapting filter of input:

In sef-adapting filter, the model frequency susceptibility of electric capacity is

$\frac{\mathrm{df}}{\mathrm{dC}}=-\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{\∂f\∂C}\right)/\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{{\∂f}^2}\right)$

In formula, f is original resonance frequency, and C is the electric capacity initial value in sef-adapting filter, λ _mfor the inverse of the equivalent inductance of NETWORK STRUCTURE PRESERVING POWER SYSTEM, equivalent capacity, equivalent resistance sum,

for derivative operation,

for secondary derivative operation.

In sef-adapting filter, the model frequency susceptibility of inductance is

$\frac{\mathrm{df}}{\mathrm{dL}}=-\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{\∂f\∂L}\right)/\left(\frac{{\∂}^2\left|{\mathrm{\λ}}_m\right|}{{\∂f}^2}\right)$

In formula, f is original resonance frequency, and L is the inductance initial value in sef-adapting filter, λ _mfor the inverse of the equivalent inductance of NETWORK STRUCTURE PRESERVING POWER SYSTEM, equivalent capacity, equivalent resistance sum,

for derivative operation,

for secondary derivative operation.

3. a kind of adaptive filter method according to claim 1, is characterized in that, the electric capacity of take in described b step carries out the iterative computation of resonance frequency as iteration input value, or take inductance and as the iterative formula that transformed value carries out the iterative computation of resonance frequency be:

$a^{(k+1)}=a^{\left(k\right)}[1+h^{\left(k\right)}/J^{\left(k\right)}]=a^{\left(k\right)}[1+(f^{\left(k\right)}-f_0)/\frac{{\∂f}^{\left(k\right)}}{{\∂\mathrm{\α}}^{\left(k\right)}}]$

A in formula (k) is capacitance or the inductance value that the k time iteration goes out, a ^(k+1)be capacitance or the inductance value that the k+1 time iteration goes out, f ^(k)be the resonant frequency value that the k time iteration goes out, f ₀for with f ^(k)the even-multiple frequency of immediate power frequency.