CN104036077A - Dynamic scanning method for electrical complex torque coefficient based on PSCAD (Power System Computer Aided Design) - Google Patents

Abstract

The invention discloses a PSCAD-based dynamic scanning method for electrical complex torque coefficients belonging to the field of power system simulation. An electrical complex torque coefficient dynamic scanning module is loaded on the electromagnetic transient software PSCAD to generate a ladder shape about the scanning frequency f According to the read scanning frequency, a disturbance is generated and added to the mechanical torque of the rotor. When the system enters a steady state again, the electromagnetic torque signal of the generator and the angular velocity response of the rotor are extracted, and the electrical complex torque coefficient is calculated to determine the Whether the ladder-shaped signal of scanning frequency f has been read. If not, continue to read the scanning frequency; if yes, stop the calculation, and complete the dynamic scanning of the electrical complex torque coefficient and the drawing of the electrical complex torque coefficient-scanning frequency relationship curve. The invention realizes the automatic scanning of the electrical complex torque coefficient method on the time-domain simulation software, and the simulation method has high speed and low cost, and is helpful for researchers to study the subsynchronous oscillation.

Description

A kind of electric multiple moment coefficient dynamic scan method based on PSCAD

Technical field

The invention belongs to electric system simulation field, relate in particular to a kind of electric multiple moment coefficient dynamic scan method based on PSCAD.

Background technology

Continuous expansion along with electric system, the measures such as the circuit series capacitor compensation that puts into operation and take in order to improve stability of power system and ability to transmit electricity of UHV (ultra-high voltage), long-distance transmission line and heavy-duty generator group and direct current transportation, except incident great economic benefit, brought new problem also to the safe and stable operation of electric system, subsynchronous oscillation of electrical power system is exactly one of its problem.

Multiple moment coefficient method is a kind of method of quantitative test subsynchronous oscillation of electrical power system problem.Two multiple moment coefficient K for the method _e(λ) and K _m(λ) electrical torque while representing sub-synchronous oscillation respectively and machine torque.Wherein, K _e(λ) and K _m(λ) imaginary part represents respectively electric part and the equivalent damping of mechanical part under oscillation frequency, by the frequency sweeping to system, and the size of these two Equivalent damping coefficients of comparison, can judge whether system exists the danger of sub-synchronous oscillation.

At present, for electric multiple moment coefficient, be mainly by simulation software, to carry out time-domain-simulation to calculate.But in simulation software, conventionally can only directly draw multiple moment coefficient rule over time, can not clearly and succinctly draw the relation between multiple moment coefficient and frequency.

Summary of the invention

For the relation of analysis frequency at length and electric multiple moment coefficient, the invention discloses a kind of electric multiple moment coefficient dynamic scan method based on PSCAD, key step comprises:

Step 1, on electro-magnetic transient software, add the multiple moment coefficient dynamic scan module of on-board electrical;

Step 2, input electric parameter and sweep parameter;

Step 3, according to arranging of pulse producer element and serializing output element, produce a stepped appearance signal about sweep frequency f;

Step 4, read the stepped appearance signal about sweep frequency f;

Step 5, the disturbance that produces a small magnitude according to the sweep frequency reading, for the electric system that enters steady state (SS), put on this disturbance on rotor mechanical torque;

Step 6, to system, again enter stable state, extract generator electromagnetic torque signal and rotor velocity response amount, calculate electric multiple moment coefficient, and draw the relation curve of electric multiple moment coefficient-sweep frequency;

Whether step 7, judgement read complete about the stepped appearance signal of sweep frequency f.If do not read completely, return to step 4, continue to read sweep frequency; If read completely, stop calculating, complete the drafting of dynamic scan and electric multiple moment coefficient-sweep frequency relation curve of electric multiple moment coefficient.

In described step 1, electric multiple moment coefficient scan module comprises: parameter setting area, and algorithm is realized district, result monitoring section, result monitoring section shows the relation curve between electric elasticity coefficient, electrical damping coefficient and sweep frequency, judges that whether it is effective; This module exchanges by data-interface and external system data, realizes parameter setting area, and algorithm is realized district, the encapsulation of result monitoring section.

In described step 2, electric parameter has: system power frequency, disturbance quantity amplitude; Sweep parameter has: initial frequency, cutoff frequency, scanning step.

In described step 4, system power frequency is 50Hz or 60Hz, and scanning step is 0.1Hz to 1Hz.

The generation form of the medium and small disturbing signal of described step 3 is:

or

Wherein, λ < 1, T _λ, respectively that frequency is amplitude and the initial phase of the pulsating torque of λ, T _λfor perunit value, between 0.005-0.05, make Δ T _mvalue be unlikely to destroy the assumed condition of system available linearization.

Described step 6 is calculated electric multiple moment coefficient and is comprised:

Step 601, generator electromagnetic torque signal and rotor velocity response amount are carried out to Fourier decomposition, draw under frequency lambda with

Step 602, the electric elasticity coefficient K when obtaining frequency and being λ _e(λ) with electrical damping moment coefficient D _e(λ), computing formula is:

$K_e\left(\mathrm{\&lambda;}\right)=-\mathrm{\&lambda;Im}\left(\frac{\mathrm{\&Delta;}{\stackrel{.}{T}}_e}{\mathrm{\&Delta;}\stackrel{.}{\mathrm{\&omega;}}}\right)$

$D_e\left(\mathrm{\&lambda;}\right)=\mathrm{Re}\left(\frac{\mathrm{\&Delta;}{\stackrel{.}{T}}_e}{\mathrm{\&Delta;}\stackrel{.}{\mathrm{\&omega;}}}\right)$

Wherein the vector form that represents generator electromagnetic torque signal; the vector form that represents rotor velocity response amount.

The beneficial effect of the invention: the present invention has not only realized the autoscan to electric multiple moment coefficient method on time-domain-simulation software, and can obtain in real time easily the relation curve of frequency and multiple moment coefficient.Emulation mode speed is fast, cost is low, be not subject to (the Flexible Alternative Current Transmission Systems of many FACTS in system, flexible AC transmitting system) device impact, to assist researcher or correlation engineering technician to utilize electric system related software (PSCAD/EMTDC) to carry out the research of subsynchronous oscillation of electrical power system aspect.

Accompanying drawing explanation

Fig. 1 be the present invention propose for electric multiple moment coefficient dynamic scan method flow diagram;

Fig. 2 is the electric multiple torque elasticity coefficient dynamic scan result of the first master pattern;

Fig. 3 is for the electric multiple torque ratio of damping dynamic scan result of the first master pattern.

Embodiment

Below in conjunction with drawings and Examples, method proposed by the invention is described further.

Be illustrated in figure 1 that the present invention proposes for electric multiple moment coefficient dynamic scan method flow diagram; The concrete steps of the method are:

1) on electro-magnetic transient software, add the multiple moment coefficient dynamic scan module of on-board electrical;

Electric multiple moment coefficient dynamic scan module comprises: parameter setting area, and algorithm is realized district, result monitoring section, result monitoring section shows the relation curve between electric elasticity coefficient, electrical damping coefficient and sweep frequency, judges that whether it is effective; This module exchanges by data-interface and external system data, realizes parameter setting area, and algorithm is realized district, the encapsulation of result monitoring section.

2) by electric multiple moment coefficient dynamic scan module input electric parameter and sweep parameter;

Electric parameter has: system power frequency, disturbance quantity amplitude; System power frequency is 50Hz or 60Hz.

Sweep parameter: initial frequency, cutoff frequency, scanning step.Scanning step is that scanning accuracy is 0.1Hz to 1Hz.

3) according to arranging of pulse producer element and serializing output element, produce a stepped appearance signal about sweep frequency f;

4) read the stepped appearance signal about sweep frequency f;

5) according to the sweep frequency reading, produce the disturbance of a small magnitude, for the electric system that enters steady state (SS), this disturbance is put on rotor mechanical torque;

The generation form of microvariations signal is:

or

Wherein, λ < 1, T _λ, respectively that frequency is amplitude and the initial phase of the pulsating torque of λ, T _λfor perunit value, between 0.005-0.05, make Δ T _mvalue be unlikely to destroy the assumed condition of system available linearization.

6) to system, again enter stable state, extract generator electromagnetic torque signal and rotor velocity response amount, calculate electric multiple moment coefficient, and draw the relation curve of electric multiple moment coefficient-sweep frequency;

The concrete calculation procedure of electric multiple moment coefficient is:

I) generator electromagnetic torque signal and rotor velocity response amount are carried out to Fourier decomposition, draw under frequency lambda with wherein the vector form that represents generator electromagnetic torque signal; the vector form that represents rotor velocity response amount;

Electric elasticity coefficient K when II) obtaining frequency and be λ _e(λ) with electrical damping moment coefficient D _e(λ), computing formula is:

$K_e\left(\mathrm{\&lambda;}\right)=-\mathrm{\&lambda;Im}\left(\frac{\mathrm{\&Delta;}{\stackrel{.}{T}}_e}{\mathrm{\&Delta;}\stackrel{.}{\mathrm{\&omega;}}}\right)$

$D_e\left(\mathrm{\&lambda;}\right)=\mathrm{Re}\left(\frac{\mathrm{\&Delta;}{\stackrel{.}{T}}_e}{\mathrm{\&Delta;}\stackrel{.}{\mathrm{\&omega;}}}\right)$

7) whether judgement reads complete about the stepped appearance signal of sweep frequency f.If do not read completely, return to step 4), continue to read sweep frequency; If read completely, stop calculating, complete the drafting of dynamic scan and electric multiple moment coefficient-sweep frequency relation curve of electric multiple moment coefficient.

Here subsynchronous the first master pattern of take is introduced electric multiple moment coefficient dynamic scan method as example.

Step 1: it is 20Hz that preliminary sweep frequency is set, and frequency sweeping step-length is 0.1Hz, and cut-off sweep frequency is 55Hz.

Step 2: produce a stepped appearance signal about sweep frequency f according to arranging of pulse producer element and serializing output element;

Step 3: read the stepped appearance signal about sweep frequency f;

Step 4: produce a microvariations signal according to the sweep frequency reading here T _λget 0.01, get 0.

Step 5: for the electric system that enters steady state (SS), this disturbing signal is put on rotor mechanical torque.

Step 6: apply after perturbing torque, emulation always enters stable state again to system, extracts generator electromagnetic torque signal and rotor velocity signal.

Step 7: above-mentioned 2 amounts are carried out to Fourier decomposition, draw under frequency lambda with according to following formula, obtain electric elasticity coefficient K _e(λ) with electrical damping moment coefficient D _e(λ), and draw the relation curve of electric multiple moment coefficient-sweep frequency:

$K_e\left(\mathrm{\&lambda;}\right)=\mathrm{j\&omega;Im}\left(\frac{\mathrm{\&Delta;}{\stackrel{.}{T}}_e}{\mathrm{\&Delta;}\stackrel{.}{\mathrm{\&omega;}}}\right)K_e\left(\mathrm{\&lambda;}\right)=-\mathrm{\&lambda;Im}\left(\frac{\mathrm{\&Delta;}{\stackrel{.}{T}}_e}{\mathrm{\&Delta;}\stackrel{.}{\mathrm{\&omega;}}}\right)$

$D_e\left(\mathrm{\&lambda;}\right)=\mathrm{Re}\left(\frac{\mathrm{\&Delta;}{\stackrel{.}{T}}_e}{\mathrm{\&Delta;}\stackrel{.}{\mathrm{\&omega;}}}\right)$

Step 8: whether judgement reads complete about the stepped appearance signal of sweep frequency f.If do not read completely, return to step 4), continue to read sweep frequency; If read completely, stop calculating, complete the drafting of dynamic scan and electric multiple moment coefficient-sweep frequency relation curve of electric multiple moment coefficient.

Researcher or correlation engineering technician utilize electric system related software (PSCAD/EMTDC) to complete electric multiple moment coefficient frequency characteristic dynamic scan by above-mentioned concrete steps.By this two CURVE STUDY system electrical part elasticity coefficient frequency characteristics and ratio of damping frequency characteristic, particularly ratio of damping frequency characteristic, it is the basis of research subsynchronous oscillation of electrical power system.Specifically can be used for the impact on system electrical damping under the different situations such as judgment means input, parameter change, control strategy variation.

Be electrical damping moment coefficient and the electric multiple torque elasticity coefficient dynamic scan result of the first master pattern as shown in Figures 2 and 3: for the simple power system with series capacitor compensation, K _e(λ) numerical value is less, near each axle is nature torsion frequency, no matter how series capacitor compensation degree changes, and K _m(λ)+K _e(λ)=0 corresponding frequency and K _e(λ) frequency phase-difference at=0 place is all very little.

When stator loop is connected with external circuit, particularly have in the external circuit situation of series compensation capacitance, along with the increase of series compensation degree, the negative damping that electrical subsystem produces is also along with increase; From electrical damping frequency characteristic, can find out, at natural torsion frequency place, the electrical damping coefficient of electrical subsystem is minimum, may be even negative value.

The above; be only the present invention's embodiment preferably, but protection scope of the present invention is not limited to this, is anyly familiar with in technical scope that those skilled in the art disclose in the present invention; the variation that can expect easily or replacement, within all should being encompassed in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.

Claims (6)

1. a dynamic scanning method for electrical complex torque coefficients based on PSCAD, is characterized in that the main steps include: Step 1. Load the electrical complex torque coefficient dynamic scanning module on the electromagnetic transient software; Step 2, input electrical parameters and scanning parameters; Step 3, according to the settings of the pulse generator element and the serialized output element, generate a ladder-shaped signal about the scanning frequency f; Step 4, read the ladder-shaped signal about the scanning frequency f; Step 5. Generate a small-amplitude disturbance according to the read scanning frequency, and apply this disturbance to the mechanical torque of the rotor for the power system that has entered a stable state; Step 6, until the system enters the steady state again, extract the generator electromagnetic torque signal and the rotor angular velocity response, calculate the electrical complex torque coefficient, and draw the relationship curve of the electrical complex torque coefficient-scanning frequency; Step 7, judge whether the ladder-shaped signal about the scanning frequency f has been read, if not, return to step 4, and continue to read the scanning frequency; if the reading is complete, stop the calculation, and complete the calculation of the electrical complex torque coefficient Dynamic sweep and plotting of electrical complex torque coefficient versus sweep frequency. 2. The method according to claim 1, characterized in that, in the step 1, the electric complex torque coefficient scanning module comprises: a parameter setting area, an algorithm realization area, a result monitoring area, and the result monitoring area displays the electrical elastic coefficient, electrical The relationship curve between the damping coefficient and the scanning frequency can be used to judge whether it is valid; the module exchanges data with the external system through the data interface, and realizes the encapsulation of the parameter setting area, the algorithm realization area, and the result monitoring area. 3. The method according to claim 1, characterized in that the electrical parameters in the step 2 include: system power frequency, disturbance amplitude; and the scanning parameters include: starting frequency, cut-off frequency, and scanning step size. 4. The method according to claim 1, characterized in that, in the step 4, the power frequency of the system is 50 Hz or 60 Hz, and the scanning step is 0.1 Hz to 1 Hz. 5. The method according to claim 1, characterized in that, the generation form of the small disturbance signal in the step 3 is: or Among them, λ<1, T _λ , are the amplitude and initial phase of the pulsating torque with frequency λ respectively, and T _λ is the per unit value, between 0.005-0.05, so that the value of ΔT _m will not destroy the assumption that the system can be linearized. 6. The method according to claim 1, wherein said step 6 calculating the electrical complex torque coefficient comprises: Step 601, perform Fourier decomposition on the electromagnetic torque signal of the generator and the angular velocity response of the rotor to obtain the and Step 602, obtain the electrical elastic coefficient K _e (λ) and the electrical damping torque coefficient D _e (λ) when the frequency is λ, the calculation formula is: ${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; \&lambda;\; Im</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\stackrel{<span\; class="notranslate">\; .</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\stackrel{<span\; class="notranslate">\; .</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}}<span\; class="notranslate">\; )</span>$ ${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; Re</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\stackrel{<span\; class="notranslate">\; .</span>}{\mathrm{<span\; class="notranslate">\; T</span>}}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\stackrel{<span\; class="notranslate">\; .</span>}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}}<span\; class="notranslate">\; )</span>$ in Represents the vector form of the generator electromagnetic torque signal; Indicates the vector form of the rotor angular velocity response.