CN111697596A - System for suppressing oscillation of power system - Google Patents
System for suppressing oscillation of power system Download PDFInfo
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- CN111697596A CN111697596A CN202010636244.4A CN202010636244A CN111697596A CN 111697596 A CN111697596 A CN 111697596A CN 202010636244 A CN202010636244 A CN 202010636244A CN 111697596 A CN111697596 A CN 111697596A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
Abstract
The invention discloses a system for inhibiting oscillation of a power system, which relates to the technical field of power systems and comprises a parallel electric power signal processing type module, a rotating speed deviation processing module, an energy storage module and a conversion module, wherein the parallel electric power signal processing type module, the rotating speed deviation processing module, the energy storage module and the conversion module are connected in parallel, the system voltage Us is taken as a reference vector, the amplitude of an output voltage fundamental wave of the conversion module is taken as Ui, the voltage Ui of the conversion module is taken as an angle leading the system voltage Us, the loss of a switching device, the connection reactance and the reduced impedance Z of a transformer are R + jX, and the impedance angle a is arctan (X/R). By combining the parallel electric power signal processing module, the rotating speed deviation processing module, the energy storage module and the conversion module, the parallel energy storage type flexible alternating current power transmission energy containing additional damping control can effectively suppress power oscillation of the extra-high voltage alternating current circuit, the damping ratio of the interconnected system can be enhanced, the power oscillation on the extra-high voltage circuit can be effectively suppressed, a new technical measure is provided for the safety and stability of the large-area interconnected system, and the operation safety of the electric power system is improved.
Description
Technical Field
The present invention relates to the field of power system technology, and in particular, to a system for suppressing power system oscillations.
Background
In order to solve the problem of reverse distribution of energy resources and consumption requirements in China and meet urgent requirements of load center on power supply, clean energy development, energy conservation, emission reduction and the like, the state vigorously builds an extra-high voltage alternating current-direct current hybrid power grid. The alternating current and direct current extra-high voltage strengthens interconnection of power grids in each area, improves the economical efficiency of power grid operation, improves the capability of resisting disturbance and fault impact, inevitably causes reduction of low-frequency oscillation and damping ratio of a system, and obviously increases the risk of dynamic stability of the power grid. The Power System Stabilizer (PSS) has an important role in improving the stability of a power system as an additional excitation control, PSS configuration is widely carried out on a grid-connected unit in the power industry of China in the last two decades, the safety and the stability of the power system are continuously improved, and remarkable economic benefits and social benefits are brought. To date, PSS is still the most effective and economical preferred means of enhancing system damping and suppressing low frequency oscillations.
PSS has long been known and widely used, the principle of which is simple and easy to understand, and PSS is used for phase compensation of generator excitation systems to improve system damping based on a moment resolution method. For the single input type PSS using electric power, although the effect of improving the damping is relatively obvious, the parameter setting conforming to the angle compensation requirement has a problem of back-tuning due to the requirement of the angle compensation.
At present, although the problem of inverse modulation is solved by adopting a PSS (fitting acceleration power signal) with double input type, under the condition of rapid change of rotating speed, the problem of serious inaccuracy of synthesized acceleration power is caused because the amplitude value of the adopted torsional vibration filter is not 1 and the phase angle has the condition of large deviation. Meanwhile, the two PSSs are not sensitive to low-frequency oscillation below 0.2Hz regardless of electric power or acceleration power, and provide insufficient damping.
An effective solution to the problems in the related art has not been proposed yet.
Disclosure of Invention
Aiming at the problems in the related technology, the invention provides a system for inhibiting the oscillation of an electric power system, which realizes the effective inhibition of the power oscillation of an extra-high voltage alternating current circuit by adopting the combination of a parallel electric power signal processing module, a rotating speed deviation processing module, an energy storage module and a conversion module, thereby enhancing the damping ratio of an interconnection system, effectively inhibiting the power oscillation on the extra-high voltage circuit, providing a new technical measure for the safety and stability of a large-area interconnection system, improving the running safety of the electric power system and overcoming the technical problems in the prior related technology.
The technical scheme of the invention is realized as follows:
a system for suppressing the oscillation of electric power system is composed of parallel electric power signal processing modules, rotational speed deviation processing module, energy storage module and transform module, which includes the reference vector of system voltage Us, the amplitude of fundamental wave of output voltage of transform module, and the angle of voltage Ui before system voltage Us, the loss of switch device, the impedance of transformer, and the impedance angle a, which is arctan (X/R), and the steady-state output of said transform module is:
Pi＝(UsUicos(a―)—Us2cosa)/|Z|；
Qi＝(UsUisin(a―)—Us2sina)/|Z|。
further, the conversion module comprises active power and reactive power decoupling control, and the controller comprises outer loop control and inner loop control, wherein the outer loop control and the inner loop control are respectively connected with the active power and the reactive power decoupling control;
the outer loop control sends specified values of active power and reactive power to the inner loop control according to the requirements of the power system;
the inner ring controller is responsible for triggering control of the converter switching element, calculates output voltage and phase of the converter according to active and reactive given values controlled by the outer ring, and controls a triggering signal of the switching element according to the output voltage to realize active and reactive four-quadrant real-time regulation.
Further, an active control loop and an additional stabilizer are included on the voltage control loop, wherein Ks is represented as a stabilizer gain, and T1-T6 are time constants; kpx and K1X are proportional and integral coefficients, respectively, and X and Xref are variables and their references, respectively, whose output signals are determined to be Vsp and Vsu, respectively.
Further, the electric power signal processing module comprises an electric power signal measuring unit, a two-stage blocking unit, a three-stage lead-lag unit and a first gain amplifying unit which are connected in sequence, and is used for measuring an input electric power signal of the generator by using the electric power signal measuring unit, then performing two-stage blocking processing by using the two-stage blocking unit to obtain an electric power deviation signal, and performing lead-lag compensation processing and gain amplification processing on the electric power deviation signal by using the three-stage lead-lag unit and the first gain amplifying unit in sequence to provide a damping effect on low-frequency oscillation in a first preset frequency range.
Furthermore, the rotating speed deviation processing module comprises a rotating speed deviation measuring unit, a low-pass filtering unit, a two-stage lead-lag unit and a second gain amplifying unit which are connected in sequence, and is used for measuring an input rotating speed deviation signal of the generator by using the rotating speed deviation measuring unit, and sequentially performing low-pass filtering processing, lead-lag compensation processing and gain amplification processing on the rotating speed deviation signal by using the low-pass filtering unit, the two-stage lead-lag unit and the second gain amplifying unit so as to provide a damping effect on low-frequency oscillation in a second preset frequency range.
Further, the low-pass filtering unit comprises a low-pass filtering subunit and a band-pass filtering subunit, wherein;
the low-pass filtering subunit is used for filtering the high-frequency-band signal of the rotating speed deviation signal by adopting a low-pass filter;
and the band-pass filtering subunit is used for performing secondary filtering on the signal output by the low-pass filtering subunit by using a band-pass filter so as to acquire a rotating speed deviation signal with the frequency within a second preset frequency range.
The invention has the beneficial effects that:
the invention realizes that the parallel energy storage type flexible alternating current power transmission energy containing additional damping control effectively inhibits the power oscillation of an extra-high voltage alternating current circuit by combining a parallel electric power signal processing type module, a rotating speed deviation processing module, an energy storage module and a conversion module, can enhance the damping ratio of an interconnection system, performs two-stage blocking processing on the input electric power signal of a generator to obtain an electric power deviation signal and provide damping action for low-frequency oscillation in a first preset frequency range, and sequentially performs low-pass filtering processing, lead-lag compensation processing and gain amplification processing on the input rotating speed deviation signal of the generator in the rotating speed deviation processing module to provide damping action for the low-frequency oscillation in a second preset frequency range, effectively inhibits the power oscillation on the extra-high voltage circuit and provides a new technical measure for the safety and stability of a large-area interconnection system, the safety of the operation of the power system is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a schematic diagram of a system for damping power system oscillations in accordance with an embodiment of the present invention;
FIG. 2 is a schematic diagram of a second principle of a system for damping oscillations in an electrical power system according to an embodiment of the present invention;
FIG. 3 is a schematic illustration of a regional interconnect power system for a system for damping power system oscillations in accordance with an embodiment of the present invention;
FIG. 4 is a schematic diagram of the control principle of a system for damping oscillations in an electrical power system according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of the additional damping control principle of a system for damping power system oscillations according to an embodiment of the present invention;
fig. 6 is a schematic diagram of a linearization principle of a system for suppressing oscillation of a power system according to an embodiment of the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
According to an embodiment of the present invention, a system for damping power system oscillations is provided.
As shown in fig. 1 to 6, the system for suppressing oscillation of an electric power system according to an embodiment of the present invention includes an electric power signal processing type module, a rotational speed deviation processing module, an energy storage module, and a conversion module connected in parallel, and includes a system voltage Us as a reference vector, an output voltage fundamental wave amplitude of the conversion module is Ui, and a conversion module voltage Ui leads the system voltage Us by an angle, a switching device loss, a reduced impedance Z connecting a reactance and a transformer is R + jX, an impedance angle a is arctan (X/R), and a steady state output thereof is expressed as:
Pi＝(UsUicos(a―)—Us2cosa)/|Z|；
Qi＝(UsUisin(a―)—Us2sina)/|Z|。
by means of the scheme, the parallel connection energy storage type flexible alternating current power transmission energy containing additional damping control is combined with the electric power signal processing module, the rotating speed deviation processing module, the energy storage module and the conversion module, power oscillation of an extra-high voltage alternating current circuit is effectively suppressed, the damping ratio of an interconnection system can be enhanced, power oscillation on the extra-high voltage circuit is effectively suppressed, a new technical measure is provided for safety and stability of a large-area interconnection system, and the operation safety of an electric power system is improved.
The conversion module comprises active power and reactive power decoupling control, and the controller comprises outer loop control and inner loop control, wherein the outer loop control and the inner loop control are respectively connected with the active power and the reactive power decoupling control;
the outer loop control sends specified values of active power and reactive power to the inner loop control according to the requirements of the power system;
the inner ring controller is responsible for triggering control of the converter switching element, calculates output voltage and phase of the converter according to active and reactive given values controlled by the outer ring, and controls a triggering signal of the switching element according to the output voltage to realize active and reactive four-quadrant real-time regulation.
The voltage control circuit further comprises an active control circuit and an additional stabilizer on the voltage control circuit, wherein Ks is represented by a stabilizer gain, and T1-T6 are time constants; kpx and K1X are proportional and integral coefficients, respectively, and X and Xref are variables and their references, respectively, whose output signals are determined to be Vsp and Vsu, respectively.
The electric power signal processing module comprises an electric power signal measuring unit, a two-stage stopping unit, a three-stage lead-lag unit and a first gain amplifying unit which are connected in sequence, and is used for measuring an input electric power signal of the generator by using the electric power signal measuring unit, then performing two-stage stopping by using the two-stage stopping unit to obtain an electric power deviation signal, and performing lead-lag compensation processing and gain amplification processing on the electric power deviation signal by using the three-stage lead-lag unit and the first gain amplifying unit in sequence to provide a damping effect on low-frequency oscillation in a first preset frequency range.
The rotating speed deviation processing module comprises a rotating speed deviation measuring unit, a low-pass filtering unit, a two-stage lead-lag unit and a second gain amplifying unit which are connected in sequence, and is used for measuring an input rotating speed deviation signal of the generator by using the rotating speed deviation measuring unit, and sequentially performing low-pass filtering processing, lead-lag compensation processing and gain amplification processing on the rotating speed deviation signal by using the low-pass filtering unit, the two-stage lead-lag unit and the second gain amplifying unit so as to provide a damping effect on low-frequency oscillation in a second preset frequency range.
The low-pass filtering unit comprises a low-pass filtering subunit and a band-pass filtering subunit, wherein the low-pass filtering subunit is connected with the band-pass filtering subunit;
the low-pass filtering subunit is used for filtering the high-frequency-band signal of the rotating speed deviation signal by adopting a low-pass filter;
and the band-pass filtering subunit is used for performing secondary filtering on the signal output by the low-pass filtering subunit by using a band-pass filter so as to acquire a rotating speed deviation signal with the frequency within a second preset frequency range.
In addition, specifically, as shown in fig. 3 to fig. 6, U, P, J, f represents input voltage, active power, current, and frequency of the power system to the outer loop controller; pset and Qset represent the active and reactive power reference values of the outer loop controller to the inner loop controller.
The grids at the two ends of the line are each represented by an equivalent generator. Setting the voltage amplitudes of two ends of the line to be Y, U1 and U2 respectively, setting the phase angle to be 1 and 2, neglecting the line resistance, and setting the power transmission formula of the power transmission line as follows:
line transmission power PL can be controlled by controlling bus voltages U1, U2, and line reactance XL.
Specifically, the frequency ω of the power system is mainly related to active power, the voltage U is related to reactive power, the basic output of active power is determined by Δ ω (Δ ω ═ ω ref- ω) and a PI link, and the basic output of reactive power is determined by Δ U (Δ U ═ Uref-U) and a PI link, and the two PI links form the Pl part of the controller.
The additional damping controller is composed of a blocking link and a lead-lag correction link, the additional damping controller gives an additional reference signal to the active PI regulator, and the input signal is the active power PL of the extra-high voltage line. Calculating the fluctuation amount of power oscillation by a blocking link of the additional controller; the phase angle is compensated through a lead-lag link, so that the output can track power oscillation.
In summary, by means of the above technical solution of the present invention, by using the parallel electric power signal processing module and the rotational speed deviation processing module, and the energy storage module and the conversion module in combination, the parallel energy storage type flexible ac power transmission with additional damping control is realized to effectively suppress the power oscillation of the extra-high voltage ac line, the damping ratio of the interconnection system can be enhanced, and the input electric power signal of the generator is subjected to two-stage dc blocking processing to obtain the electric power deviation signal and provide damping effect for the low frequency oscillation within the first preset frequency range, and in the rotational speed deviation processing module, the input rotational speed deviation signal of the generator is sequentially subjected to low pass filtering processing, lead-lag compensation processing and gain amplification processing to provide damping effect for the low frequency oscillation within the second preset frequency range and effectively suppress the power oscillation on the extra-high voltage line, a new technical measure is provided for the safety and stability of the large-area interconnected system, and the operation safety of the power system is improved.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (6)
1. A system for suppressing the oscillation of an electric power system comprises an electric power signal processing type module, a rotating speed deviation processing module, an energy storage module and a conversion module which are connected in parallel, wherein the system voltage Us is taken as a reference vector, the fundamental wave amplitude of the output voltage of the conversion module is set to be Ui, the voltage Ui of the conversion module is set to lead the system voltage Us by an angle, the loss of a switching device, the reduced impedance Z which connects a reactor and a transformer is R + jX, the impedance angle a is arctan (X/R), and the steady-state output of the system is expressed as:
Pi＝(UsUicos(a―)—Us2cosa)/|Z|；
Qi＝(UsUisin(a―)—Us2sina)/|Z|。
2. the system for damping power system oscillations according to claim 1, characterized in that, said conversion module comprises an active power and reactive power decoupling control, and its controller comprises an outer loop control and an inner loop control, wherein;
the outer loop control sends specified values of active power and reactive power to the inner loop control according to the requirements of the power system;
the inner ring controller is responsible for triggering control of the converter switching element, calculates output voltage and phase of the converter according to active and reactive given values controlled by the outer ring, and controls a triggering signal of the switching element according to the output voltage to realize active and reactive four-quadrant real-time regulation.
3. The system for damping oscillations in a power system of claim 2, further comprising additional stabilizers on said active control loop and said voltage control loop indicating Ks as stabilizer gain, and T1-T6 as time constants; kpx and K1X are proportional and integral coefficients, respectively, and X and Xref are variables and their references, respectively, whose output signals are determined to be Vsp and Vsu, respectively.
4. The system for damping power system oscillations according to claim 1,
the electric power signal processing module comprises an electric power signal measuring unit, a two-stage blocking unit, a three-stage lead-lag unit and a first gain amplifying unit which are connected in sequence, and is used for measuring an input electric power signal of the generator by using the electric power signal measuring unit, then performing two-stage blocking processing by using the two-stage blocking unit to obtain an electric power deviation signal, and performing lead-lag compensation processing and gain amplification processing on the electric power deviation signal by using the three-stage lead-lag unit and the first gain amplifying unit in sequence to provide a damping effect on low-frequency oscillation in a first preset frequency range.
5. The system for suppressing oscillation of a power system as claimed in claim 1, wherein the rotational speed deviation processing module comprises a rotational speed deviation measuring unit, a low-pass filtering unit, a two-stage lead-lag unit and a second gain amplifying unit which are connected in sequence, and is used for measuring the rotational speed deviation signal of the generator input by the rotational speed deviation measuring unit and sequentially performing low-pass filtering processing, lead-lag compensation processing and gain amplification processing on the rotational speed deviation signal by the low-pass filtering unit, the two-stage lead-lag unit and the second gain amplifying unit so as to provide damping effect for low-frequency oscillation in a second preset frequency range.
6. The system for damping power system oscillations according to claim 5, characterized in that said low pass filtering unit, comprises a low pass filtering subunit and a band pass filtering subunit, wherein;
the low-pass filtering subunit is used for filtering the high-frequency-band signal of the rotating speed deviation signal by adopting a low-pass filter;
and the band-pass filtering subunit is used for performing secondary filtering on the signal output by the low-pass filtering subunit by using a band-pass filter so as to acquire a rotating speed deviation signal with the frequency within a second preset frequency range.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113189919A (en) * | 2021-05-26 | 2021-07-30 | 广东电网有限责任公司 | Control system and method for high-frequency noise power gain |
| CN113726236A (en) * | 2021-08-11 | 2021-11-30 | 上海电气风电集团股份有限公司 | Wind generating set and control system thereof |
| CN116316705A (en) * | 2023-04-14 | 2023-06-23 | 长沙学院 | Low-carbon power system oscillation suppression method based on energy storage power station |
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| CN110676859A (en) * | 2019-10-11 | 2020-01-10 | 中国电力科学研究院有限公司 | Power system stabilizer model for inhibiting global low-frequency oscillation and inhibition method |
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| 谢光龙;马智泉;张步涵;李小平;曾杰;毛承雄;: "利用并联储能型FACTS抑制特高压互联电网功率振荡" * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113189919A (en) * | 2021-05-26 | 2021-07-30 | 广东电网有限责任公司 | Control system and method for high-frequency noise power gain |
| CN113189919B (en) * | 2021-05-26 | 2022-06-17 | 广东电网有限责任公司 | Control system and method for high-frequency noise power gain |
| CN113726236A (en) * | 2021-08-11 | 2021-11-30 | 上海电气风电集团股份有限公司 | Wind generating set and control system thereof |
| CN116316705A (en) * | 2023-04-14 | 2023-06-23 | 长沙学院 | Low-carbon power system oscillation suppression method based on energy storage power station |
| CN116316705B (en) * | 2023-04-14 | 2023-09-12 | 长沙学院 | Low-carbon power system oscillation suppression method based on energy storage power station |
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Inventor after: Dong Changhai Inventor after: Zhang Ming Inventor after: Gu Dongmei Inventor after: Xia Xuejun Inventor after: Wen Qingguo Inventor after: Shi Bin Inventor after: Shang Yong Inventor after: Feng Weiping Inventor before: Dong Changhai Inventor before: Gu Dongmei |