CN106410822B - Power grid power oscillation suppressor of wide-range controllable transformer containing bidirectional thyristor - Google Patents

Power grid power oscillation suppressor of wide-range controllable transformer containing bidirectional thyristor Download PDF

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CN106410822B
CN106410822B CN201610754822.8A CN201610754822A CN106410822B CN 106410822 B CN106410822 B CN 106410822B CN 201610754822 A CN201610754822 A CN 201610754822A CN 106410822 B CN106410822 B CN 106410822B
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bidirectional thyristor
power
phase
group
transformer
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CN106410822A (en
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冯琳
汪可友
韩蓓
李国杰
江秀臣
王琨
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SHANGHAI JUDIAN ELECTRIC EQUIPMENT Co Ltd
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SHANGHAI JUDIAN ELECTRIC EQUIPMENT Co Ltd
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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
    • 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
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1878—Arrangements for adjusting, eliminating or compensating reactive power in networks using tap changing or phase shifting transformers
    • 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
    • Y02E40/30—Reactive power compensation

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Ac-Ac Conversion (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

The invention discloses a power oscillation suppressor based on a wide-range controllable transformer with a bidirectional thyristor, which comprises a controllable transformer, a power unit, a measurement and control module, a cross-phase conversion module, a filter capacitor, an input and output voltage transformer and an output current transformer, wherein the input end of the power oscillation suppressor is connected with a bus 1, and the output end of the power oscillation suppressor is connected with a bus 2 through a power transmission line. According to the invention, another two-phase winding is connected in series at the side of each phase tap of the wide-range controllable transformer, and four bidirectional thyristors are added to change the conduction direction of the cross-phase winding, so that the phase and amplitude of the output voltage of the controllable transformer are changed in the maximum range, and the adjustment of active power and reactive power is realized; when power oscillation occurs in the power grid, the active power and the reactive power output by the power oscillation suppressor are dynamically adjusted according to a control rule, so that the power grid is restored to be stable as soon as possible; the method has the characteristics of low cost and high reliability, improves the stability of the power grid and improves the damping of the system.

Description

Power grid power oscillation suppressor of wide-range controllable transformer containing bidirectional thyristor
Technical Field
The invention relates to the technical field of flexible alternating current transmission, in particular to a power oscillation suppressor based on a bidirectional thyristor.
Background
The stability of the power system is the key to the safe operation of the power grid, and once the power system is damaged, huge economic loss and catastrophic consequences are caused. In order to realize the national overall energy development and layout policy, "east-to-west power transmission, mutual supply in south and north, national networking and separation of plant networks" becomes the direction of the development of the power industry in China in the first half of the 21 st century. The interconnection of the power grids can reasonably utilize energy resources, provide mutual support, and greatly improve the economic reliability of power generation and power transmission, but simultaneously bring new problems. Along with the continuous improvement of the interconnection degree of the power network, the system is more and more huge, the operation mode is more and more complex, the difficulty of ensuring the safe and reliable operation of the system is more and more large, and the problem of the safety and stability of the power grid is more and more prominent. In a modern large power grid, all areas and all parts are mutually connected and closely related and mutually influence each other in the operation process. If the power grid structure is imperfect and the necessary safety measures are lacked, a local small disturbance or abnormal operation may cause a chain reaction of the whole system and even cause the system to be broken down in a large area. In recent years, the reform of the power industry worldwide is increasingly accelerated, and a power market under a competitive mechanism is gradually established. The open and commercial operation of electrical grids has enabled power systems to operate closer and closer to the limits of the systems. These all present new challenges for stable analysis and control. Therefore, the safety and stability problem has become one of the problems to be studied and solved seriously in developing large power systems.
The stability problem of the system is whether the system can be restored to an allowable equilibrium state after various disturbances. The disturbance comprises sudden load change, generator fault or sudden output change, power transmission line fault and the like. Under disturbance, the system may have power angle oscillation, power oscillation, voltage oscillation, frequency instability, and the like.
The problem of power oscillation is generally the problem of insufficient damping of system oscillation, and the currently adopted methods mainly utilize a Power System Stabilizer (PSS) to control generator excitation so as to improve the damping of system oscillation, and in addition, measures such as converter control for modulating High Voltage Direct Current (HVDC) transmission by using an additional stable signal and flexible transmission equipment FACTS (such as controllable series compensation, static reactive power compensator and the like) control and the like are adopted.
Disclosure of Invention
The invention aims to provide a power oscillation suppressor based on a wide-range controllable transformer and a suppression method thereof, when power oscillation occurs in a power grid, the power oscillation suppressor dynamically controls the amplitude and phase angle of voltage output by a tap of the transformer through a rapid power electronic switch by utilizing a multi-tap transformer of an existing transmission line according to a control rule, so that active power and reactive power output by the power oscillation suppressor are dynamically adjusted, and the power grid is recovered to be stable as soon as possible; the capacity of the power electronic power tube for controlling the tap joint of the controllable transformer is only one part of the capacity of the controllable transformer, so the cost is low and the reliability is high. The method can improve the system stability and reliability of the power system, and the power grid in China really becomes a strong intelligent power grid.
The technical solution of the invention is as follows:
a power grid power oscillation suppressor based on a wide-range controllable transformer including a triac, characterized in that the device comprises: controllable transformer of wide range, measurement and control module, first power unit and second power unit, cross phase transition module, third filter capacitor and fourth filter capacitor, input voltage transformer, output voltage transformer and output current transformer:
the secondary side of the wide range controllable transformer includes a main tap "1", a positive tap "1 + N" and a negative tap "1-N";
the first power unit comprises a first group of power tubes, a second group of power tubes, a first filter inductor and a first filter capacitor, wherein the first group of power tubes and the second group of power tubes are respectively formed by connecting 2 IGBT in reverse series, one end of the first group of power tubes is connected with a positive tap '1 + N' of the secondary side of the wide-range controllable transformer, one end of the second group of power tubes is connected with a negative tap '1-N' of the secondary side of the wide-range controllable transformer, the other ends of the first group of power tubes and the second group of power tubes are connected with one end of the first filter inductor, the other end of the first filter inductor is connected with the input end of the cross-phase conversion module, the first filter capacitor is connected between the positive tap '1 + N' and the negative tap '1-N' of the secondary side of the wide-range controllable transformer, the control ends of the first group of power tubes and the second group of power tubes are connected with the corresponding control ends of the measurement and control module;
the second power unit consists of a third group of power tubes, a fourth group of power tubes, a second filter inductor and a second filter capacitor, the third group of power tubes and the fourth group of power tubes are formed by connecting 2 insulated gate bipolar transistors in series in an opposite direction, one end of the third group of power tubes is connected with the first output end of the cross phase conversion module, one end of the fourth group of power tubes is connected with the second output end of the cross phase conversion module, namely the input ends of the cross phase conversion modules are connected, the other ends of the third group of power tubes and the fourth group of power tubes are simultaneously connected with one end of the second filter inductor, the other end of the second filter inductor is connected with one end of the output current transformer, the second filter capacitor is connected between the output ends of the cross phase conversion modules, the control ends of the third group of power tubes and the fourth group of power tubes are connected with the corresponding control ends of the measurement and control module;
the cross phase conversion module consists of a winding consisting of a positive tap and a negative tap on the secondary side of the wide-range controllable transformer, and a first bidirectional thyristor, a second bidirectional thyristor, a third bidirectional thyristor and a fourth bidirectional thyristor;
one end of the third filter capacitor is connected with a main joint '1' of the secondary side of the wide-range controllable transformer, and the other end of the third filter capacitor is connected with the first filter inductor;
one end of the fourth filter capacitor is connected with the first filter inductor, and the other end of the fourth filter capacitor is connected with the second filter inductor;
one side of the input voltage transformer is connected with a primary side input voltage main circuit of the wide-range controllable transformer, and a voltage signal output end is connected with a voltage signal input port of the measurement and control module;
one side of the output voltage transformer is connected with the secondary side output voltage main circuit of the wide-range controllable transformer, and a voltage signal output end is connected with a voltage signal input port of the measurement and control module;
the output current transformer is connected in series in an output main circuit of the wide-range controllable transformer, and a current signal output end of the output current transformer is connected with a current signal input port of the measurement and control module;
the output end of the control signal of the measurement and control module is respectively connected with the control ends of the first group of power tubes and the second group of power tubes of the first power unit, the control ends of the third group of power tubes and the fourth group of power tubes of the second power unit and the control ends of the first bidirectional thyristor, the second bidirectional thyristor, the third bidirectional thyristor and the fourth bidirectional thyristor, the input end of the measurement and control module is connected with the output end of the voltage and current measurement device, and the measurement and control module is connected with the upper computer.
The measuring and controlling module is a digital signal processor, a singlechip or a computer.
The first group of power tubes, the second group of power tubes, the third group of power tubes and the fourth group of power tubes are integrated gate commutated thyristors, gate conducted thyristors, metal oxide semiconductor field effect transistors or other power electronic switches.
Phase A: NV (network video) with cross-phase conversion module connected in series from C phasecinNV with windings and B phases connected in seriesbinThe winding is composed of a first bidirectional thyristor, a second bidirectional thyristor, a third bidirectional thyristor and a fourth bidirectional thyristor, one end of the first bidirectional thyristor is connected with the other end of the first filter inductor, and the other end of the first bidirectional thyristor is connected with the C-phase NVcinNegative tap of winding, the C phase NVcinPositive tap of winding and said B-phase NVbinNegative tap of winding, the B-phase NVbinThe positive tap of the winding is connected with one end of a third bidirectional thyristor, and the other end of the third bidirectional thyristor is connected with the input end of a third power tube of the second power unit; one end of the second bidirectional thyristor is connected with one end of the first bidirectional thyristor, and the other end of the second bidirectional thyristor is connected with one end of the third bidirectional thyristor; one end of the fourth bidirectional thyristor is connected with the other end of the first bidirectional thyristor, and the other end of the first bidirectional thyristor is connected with the other end of the third bidirectional thyristor;
phase B: NV (network video) with cross-phase conversion module connected in series from A phaseainNV with windings and C-phase seriescinThe winding is composed of a first bidirectional thyristor, a second bidirectional thyristor, a third bidirectional thyristor and a fourth bidirectional thyristor, one end of the first bidirectional thyristor is connected with the other end of the first filter inductor, and the other end of the first bidirectional thyristor is connected with the A-phase NVainNegative tap of winding, the A-phase NVAinPositive tap of winding and said C-phase NVcinNegative tap of winding, the C phase NVcinThe positive tap of the winding is connected with one end of a third bidirectional thyristor, and the other end of the third bidirectional thyristor is connected with the input end of a third power tube of the second power unit; one end of the second bidirectional thyristor is connected with one end of the first bidirectional thyristor, and the other end of the second bidirectional thyristor is connected with one end of the third bidirectional thyristor; one end of the fourth bidirectional thyristor is connected with the other end of the first bidirectional thyristor, and the other end of the first bidirectional thyristor is connected with the other end of the third bidirectional thyristor;
and C phase: NV (network video) with B-phase serial connection of cross-phase conversion modulebinNV with windings and A phase in seriesainThe winding is composed of a first bidirectional thyristor, a second bidirectional thyristor, a third bidirectional thyristor and a fourth bidirectional thyristor, one end of the first bidirectional thyristor is connected with the other end of the first filter inductor, and the other end of the first bidirectional thyristor is connected with the B-phase NVbinNegative tap of winding, the B-phase NVbinPositive tap of winding and said phase A NVainNegative tap of winding, the A-phase NVainThe positive tap of the winding is connected with one end of a third bidirectional thyristor, and the other end of the third bidirectional thyristor is connected with the input end of a third power tube of the second power unit; one end of the second bidirectional thyristor is connected with one end of the first bidirectional thyristor, and the other end of the second bidirectional thyristor is connected with one end of the third bidirectional thyristor; one end of the fourth bidirectional thyristor is connected with the other end of the first bidirectional thyristor, and the other end of the first bidirectional thyristor is connected with the other end of the third bidirectional thyristor.
The method for suppressing the power oscillation of the power grid by using the power oscillation suppressor of the power grid comprises the following specific steps of:
step 1) connecting the power grid power oscillation suppressor between two power grids in series;
step 2) setting three-phase input voltages of the wide-range controllable transformer as follows:
Vain＝V1sin(ω0t)
Vbin＝V1sin(ω0t+120°)
Vcin＝V1sin(ω0t-120°)
wherein, VainIs an A-phase input voltage, VbinIs a B-phase input voltage, VcinThe C-phase input voltage is hereinafter referred to as a single-phase voltage and a single-phase current.
During power oscillation, the measurement and control module of the power oscillation suppressor specifically adjusts the output power as follows:
firstly, initializing, namely setting the following parameters in the controller, wherein all power and voltage parameters adopt per unit values:
active power initial value P output by power oscillation suppressor0；
Reactive power initial value Q output by power oscillation suppressor0；
The tap changing ratio N of the controllable transformer;
ω0an angular frequency corresponding to 50 or 60 Hz;
control coefficient k of first PI control modulep1And ki1，1≤kp1≤100,1≤ki1The initial value is 10 and is set by an operator according to the running condition of the power grid, the larger the power is, the larger the coefficient value is, and the maximum value of the coefficient value is 100 when the rated power is;
control coefficient k of second PI control modulep2And ki2，1≤kp2≤100,1≤ki2The initial value is 10 and is set by an operator according to the running condition of the power grid, the larger the power is, the larger the coefficient value is, and the maximum value of the coefficient value is 100 when the rated power is;
collecting input voltage, output voltage and output current of the controllable transformer in real time, and calculating output active power and reactive power according to the output voltage and the output current;
regulating the output active power and reactive power of the controllable transformer by changing the modulation signal of a tap switch of the controllable transformer according to the running condition of the power grid;
1. the output active power regulation is carried out according to the following steps:
311, calculating the input value mu of the first PI control module by the first comparison module according to the following formulaS1：
μS1＝P0-P，
Wherein, P is an active power value input by the first comparison module;
step 312, the first PI control module performs control operation after receiving the output of the first comparison module, and outputs a corresponding control quantity muC1The formula is as follows:
μC1＝kp1μS1+ki1∫μS1dt；
and 313, the first addition module calculates the phase angle theta of the fundamental wave of the output voltage of the controllable transformer according to the following formula:
θ＝θ0+μC1，
wherein, theta0Setting an initial value for the phase angle of the output voltage of the controllable transformer;
2. the output reactive power regulation is carried out according to the following steps:
step 321, calculating the input value μ of the second PI control module by the second comparison module according to the following formulaS2：
μS2＝Q0-Q，
Q is a reactive power value input by the first comparison module;
step 322, the second PI control module performs control operation after receiving the output of the second comparison module, and outputs the corresponding control quantity muC2The calculation formula is as follows:
μC2＝kp2μS2+ki2∫μS2dt；
323, calculating the amplitude of the fundamental wave of the output voltage of the controllable transformer by the second addition module according to the following formula
Wherein the content of the first and second substances,outputting an initial amplitude of a voltage fundamental wave for the controllable transformer;
and fourthly, calculating a duty ratio control signal D1 of the first power unit and a duty ratio control signal D2 of the second power unit:
setting the input voltage of the controllable transformer collected in real time as Vin＝V1sin(ω0t) in which V1Is an input voltage VinAmplitude of
The phase angle theta and the amplitude value of the fundamental wave of the output voltage of the controllable transformer obtained in the step are measuredSubstituting into the following formula to obtain
Let K1For switching signals of the first and third bidirectional thyristors, K2For the second and fourth triac signals, the control signal has two operating states:
(1) when the voltage phase angle theta takes "+", K1＝1，K2When the two-phase winding is in a positive direction, the first bidirectional thyristor and the third bidirectional thyristor are switched on, the second bidirectional thyristor and the fourth bidirectional thyristor are switched off, and the two-phase winding is switched on;
(2) when the voltage phase angle theta takes "-", K1＝0，K2When the two-phase winding is in reverse conduction, the first bidirectional thyristor and the third bidirectional thyristor are turned off, the second bidirectional thyristor and the fourth bidirectional thyristor are turned on, and the two-phase winding is turned on in the reverse direction;
according to pulse width modulation duty ratio D1And D2Controlling the conduction of the insulated gate bipolar transistor to the insulated gate bipolar transistor pulse width modulation signal;
sixthly, repeating the steps from the second step to the fifth step, and modulating the duty ratio D according to the obtained pulse width1And D2And the adjustment and control of the dynamic power flow of the power grid are realized by controlling the conduction of the insulated gate bipolar transistor.
The invention has the following technical effects and characteristics:
1. the power tube only needs to control the conduction of the controllable transformer tap, so the cost is low, and the problem of high cost of the conventional FACTS device is solved;
2. the controllable transformer is used for dynamically controlling active power and reactive power, so that when power oscillation occurs in a power grid fault, the vibration of the power grid can be effectively inhibited, and the stability of the system is improved.
Drawings
Fig. 1 is a schematic diagram of a power oscillation suppressor based on a wide range controllable transformer with a triac.
Fig. 2 is a block diagram of a power oscillation suppressor based on a wide range controllable transformer including a triac.
Fig. 3 is a control law diagram of a power oscillation suppressor based on a wide range controllable transformer with a triac.
Fig. 4 is a flow chart of a process for a power oscillation suppressor based on a wide range controllable transformer with a triac.
Detailed Description
The present invention will be further described with reference to the following examples and drawings, but the scope of the present invention should not be limited thereto.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a power oscillation suppressor based on a wide-range controllable transformer including a triac according to the present invention. It can be seen from the figure that a grid power oscillation suppressor based on a wide-range controllable transformer with a bidirectional thyristor comprises: the system comprises a wide-range controllable transformer 1, a measurement and control module 2, a first power unit 3, a second power unit 4, a cross-phase conversion module 5, a third filter capacitor 6, a fourth filter capacitor 7, an input voltage transformer 8, an output voltage transformer 9 and an output current transformer 10:
the secondary side of the wide range controllable transformer 1 comprises a main tap "1" and a positive tap "1 + N" and a negative tap "1-N";
the first power unit 3 consists of a first group of power tubes S1A second group of power tubes S2Filter inductor Lf1And a filter capacitor Cf1A first group of power tubes S of the first power unit 31And a second group of power tubes S2Each of the power transistors comprises 2 insulated gate bipolar transistors which are connected in series in an opposite direction, and the power transistors S of the first group1One end of which is connected with a positive tap '1 + N' of the secondary side of the wide-range controllable transformer 1, and a second group of power tubes S2Is connected to the negative taps "1-N" of the secondary side of said wide range controllable transformer 1, said first set of power transistors S1And a second group of power tubes S2And the other end of the filter inductor Lf1Is connected to one end of the filter inductor Lf1The other end of the filter capacitor C is connected with the input end of the cross phase conversion module 5f1Connected between the positive tap (1 + N) and the negative tap (1-N) of the secondary side of the wide range controllable transformer (1), and the first group of power tubes (S)1And a second group of power tubes S2The control end of the measuring and controlling module 2 is connected with the corresponding control end of the measuring and controlling module;
the second power unit 4 consists of a third group of power tubes S3And a fourth group of power tubes S4Filter inductor Lf2And a filter capacitor Cf2The third group of power tubes S of the second power unit 43And a fourth group of power tubes S4Each of the three power transistors comprises 2 insulated gate bipolar transistors which are connected in series in an opposite direction, and the third group of power transistors S3Is connected with one end of the output end of the cross phase conversion module 5, and a fourth group of power tubes S4Is connected with the other end of the output end of the cross phase conversion module 5, and the third group of power tubes S3And a fourth group of power tubes S4And the other end of the filter inductor Lf2Is connected to one end of the filter inductor Lf2The other end of the filter capacitor C is connected with the output current transformer (10), and the filter capacitor Cf2Connected between the output ends of the cross-phase conversion module 5, and the third group of power tubes S31And a fourth group of power tubes S4The control end of the measuring and controlling module 2 is connected with the corresponding control end of the measuring and controlling module;
the cross phase conversion module 5 consists of a winding consisting of a positive tap 11 and a negative tap 12 of the secondary side of the controllable transformer 1, which are the other two phases of the cross phase winding, and four bidirectional thyristors;
taking phase a as an example, the cross-phase conversion module 5 is composed of NV connected in series by phase CcinNV with windings and B phases connected in seriesbinA winding and four bidirectional thyristors, the cross-phase being serially connected into the bidirectional thyristor S of the modulea1One end of the filter inductor Lf1Is connected with the other end of the C-phase NV cable, and the other end of the C-phase NV cable is connected with the C-phase NV cablecinNegative winding taps 11 connected, C-phase NVcinPositive winding tap and said B-phase NVbinNegative tap of winding connected, B-phase NVbinWinding positive tap and the bidirectional thyristor Sa3Is connected to one end of the bidirectional thyristor Sa3And the other end of the power unit 4 and the power tube S of the power unit 43The corresponding input ends are connected; the bidirectional thyristor Sa2One end of (2) and the bidirectional thyristor Sa1One end is connected with the bidirectional thyristor S and the other end is connected with the bidirectional thyristor Sa3One end is connected; the bidirectional thyristor Sa4One end of (2) and the bidirectional thyristor Sa1The other end is connected with the bidirectional thyristor Sa3The other end is connected;
one end of the filter capacitor 6 is connected with the secondary side of the wide-range controllable transformer 1 through a main joint '1', and the other end of the filter capacitor is connected with the filter inductor Lf1Connecting;
the filterOne end of a wave capacitor 7 and the filter inductor Lf1Connected to the other end of said filter inductor Lf2Connecting;
one side of the input voltage transformer 8 is connected with a primary side input voltage main circuit of the wide-range controllable transformer, and a voltage signal output end is connected with a voltage signal input port of the measurement and control module 2;
one side of the output voltage transformer 9 is connected with a secondary output voltage main circuit of the wide-range controllable transformer, and a voltage signal output end is connected with a voltage signal input port of the measurement and control module 2;
the output current transformer 10 is connected in series in the output main circuit of the wide-range controllable transformer, and the current signal output end of the output current transformer is connected with the current signal input port of the measurement and control module 2;
the measurement and control module 2 comprises a first PI control module, a second PI control module, a first comparison module, a second comparison module, a first addition module and a second addition module; the control signal output end of the measurement and control module 2 is respectively connected with the first group of power tubes S of the power unit 31And a second group of power tubes S2The control terminal of (3), the third group of power tubes (S) of the power unit (4)3And a fourth group of power tubes S4The control end of the measuring and controlling module 2 is connected with the upper computer.
The change-over switch included in the cross-phase change-over module 5 is a bidirectional thyristor.
The measuring and controlling module 2 is a digital signal processor, a singlechip or a computer.
Applying the power oscillation suppressor based on the controllable transformer, which is structured as shown in fig. 2, to the power grid shown in fig. 1, and programming according to a program flow chart (fig. 4) written according to the control law shown in fig. 3 to realize the function of power oscillation suppression; according to simulation results, the photovoltaic cell-based power grid power oscillation suppressor can effectively suppress power oscillation, and stability of the system is improved.
The method for suppressing the power oscillation of the power grid by using the power oscillation suppressor of the power grid comprises the following steps:
step 1, initialization, namely setting the following parameters in the controller, wherein all power and voltage parameters adopt per unit values:
active power initial value P output by power oscillation suppressor0；
Reactive power initial value Q output by power oscillation suppressor0；
The tap changing ratio N of the controllable transformer;
omega 0 is the angular frequency corresponding to 50 or 60 Hz;
first PI control Module control coefficient kp1And ki1，1≤kp1≤100,1≤ki1The initial value is 10 and is set by an operator according to the running condition of the power grid, the larger the power is, the larger the coefficient value is, and the maximum value of the coefficient value is 100 when the rated power is;
second PI control Module control coefficient kp2And ki2，1≤kp2≤100,1≤ki2The initial value is 10 and is set by an operator according to the running condition of the power grid, the larger the power is, the larger the coefficient value is, and the maximum value of the coefficient value is 100 when the rated power is;
adjusting reactive power and/or active power according to the operation condition of the power grid;
the active power and the reactive power output by the controllable transformer tap switch are adjusted by changing a modulation signal of the controllable transformer tap switch;
step 2, the active power regulation of the power grid is executed according to the following steps:
step 21, calculating the input value mu of the first PI control module through the first comparison module according to the following formulaS1：
μS1＝P0-P, where P is the value of the active power input by the first comparing module;
step 22, the first PI control module performs control operation after receiving the output of the first comparison module, and outputs corresponding control quantity muC1The calculation formula is as follows: mu.sC1＝kp1μS1+ki1∫μS1dt，
Wherein kp1 and ki1 are control coefficients of the first PI control module;
and 23, calculating the phase angle theta of the fundamental wave of the output voltage of the controllable transformer according to the following formula by the first addition module:
θ＝θ0+μC1；
and 3, adjusting the reactive power of the power grid according to the following steps:
step 31, calculating the input value mu of the second PI control module through the second comparison module according to the following formulaS2：
μS2＝Q0-Q, wherein Q is the reactive power value input by the first comparison module;
step 32, the second PI control module carries out control operation after receiving the output of the second comparison module and outputs corresponding control quantity muC2The calculation formula is as follows:
μC2＝kp2μS2+ki2∫μS2dt，
wherein kp2 and ki2 are control coefficients of the second PI control module;
and step 33, calculating the amplitude of the fundamental wave of the output voltage of the controllable transformer by the second addition module according to the following formula Wherein the content of the first and second substances,outputting an initial amplitude of a voltage fundamental wave for the controllable transformer;
and 4, calculating to obtain a modulation coefficient and an initial phase value through a formula:
real-time acquisition of input voltage V of controllable transformerin＝V1sin(ω0t), where V1 is the magnitude of the input voltage Vin;
the phase angle theta and the amplitude value of the fundamental wave of the output voltage of the controllable transformer obtained by the calculationSubstituting into the following formula to obtain
Let K1Is a first bidirectional thyristor Sa1And a third bidirectional thyristor Sa3Switching signal, K2Is a second bidirectional thyristor Sa2And a fourth bidirectional thyristor Sa4The switch signal has two working states:
(1) when the voltage phase angle theta takes "+", K1＝1，K20, first bidirectional thyristor Sa1And a third bidirectional thyristor Sa3On, the second triac Sa2 and the fourth triac Sa4 are turned off, and the two-phase winding is conducted in the forward direction;
(2) when the voltage phase angle theta takes "-", K1＝0，K21, a first bidirectional thyristor Sa1And a third bidirectional thyristor Sa3Off, second bidirectional thyristor Sa2And a fourth bidirectional thyristor Sa4Conducting, and conducting the two-phase windings reversely;
the duty cycle control signal D of the power unit 3 in the pulse width modulated signal of the IGBT is then obtained1And a power unit 4 duty ratio control signal D2；
Step 5, modulating the duty ratio D according to the pulse width1And D2Controlling the conduction of the insulated gate bipolar transistor to the insulated gate bipolar transistor pulse width modulation signal;
step 6, repeating the steps 2 to 5, and modulating the duty ratio D according to the obtained pulse width1And D2By controlling the insulated gate bipolarAnd the conduction of the type transistor realizes the regulation and control of the dynamic power flow of the power grid.
And the control rules of the first PI control module and the second PI control module are proportional integral derivative control modes.

Claims (4)

1. A grid power oscillation suppressor based on a wide range controllable transformer including a triac, comprising: the device comprises a wide-range controllable transformer (1), a measurement and control module (2), a first power unit (3), a second power unit (4), a cross-phase conversion module (5), a third filter capacitor (6), a fourth filter capacitor (7), an input voltage transformer (8), an output voltage transformer (9) and an output current transformer (10):
the secondary side of the wide-range controllable transformer (1) comprises a main joint '1', a positive tap '1 + N' and a negative tap '1-N';
the first power unit (3) consists of a first group of power tubes (S)1) A second group of power tubes (S)2) A first filter inductor (L)f1) And a first filter capacitor (C)f1) The first group of power tubes (S)1) And a second group of power tubes (S)2) Each composed of 2 insulated gate bipolar transistors connected in reverse series, the first group of power tubes (S)1) One end of the second group of power tubes (S) is connected with the positive tap (1 + N) of the secondary side of the wide-range controllable transformer (1)2) Is connected to the negative tap '1-N' of the secondary side of said wide range controllable transformer (1), said first set of power transistors (S)1) And a second group of power tubes (S)2) And said first filter inductance (L)f1) Is connected to one terminal of the first filter inductor (L)f1) Is connected with the input end of the cross phase conversion module (5), and the first filter capacitor (C)f1) Connected between the positive tap '1 + N' and the negative tap '1-N' of the secondary side of the wide range controllable transformer (1), the first group of power tubes (S)1) And a second group of power tubes (S)2) The control end of the measuring and controlling module (2) is connected with the corresponding control end of the measuring and controlling module;
said secondThe power unit (4) is composed of a third group of power tubes (S)3) And a fourth group of power tubes (S)4) A second filter inductor (L)f2) And a second filter capacitor (C)f2) The third group of power tubes (S)3) And a fourth group of power tubes (S)4) Each composed of 2 insulated gate bipolar transistors connected in reverse series, and the third group of power tubes (S)3) Is connected to the first output of the cross-phase conversion module (5), and a fourth group of power tubes (S)4) Is connected to a second output of said cross-phase conversion module (5), i.e. the input of the cross-phase conversion module (5), and said third set of power tubes (S)3) And a fourth group of power tubes (S)4) And the other end of said second filter inductor (L) simultaneously with said second filter inductor (L)f2) Is connected to one terminal of the second filter inductor (L)f2) Is connected with one end of the output current transformer (10), and the second filter capacitor (C)f2) Connected between the outputs of the cross-phase conversion module (5), and the third group of power tubes (S)3) And a fourth group of power tubes (S)4) The control end of the measuring and controlling module (2) is connected with the corresponding control end of the measuring and controlling module;
the cross phase conversion module (5) comprises a winding and a first bidirectional thyristor (S), wherein the winding consists of a secondary positive tap (11) and a secondary negative tap (12) of the wide-range controllable transformer (1)a1) A second bidirectional thyristor (S)a2) A third bidirectional thyristor (S)a3) And the fourth bidirectional thyristor (S)a4) Composition is carried out;
one end of the third filter capacitor (6) is connected with the main joint '1' of the secondary side of the wide-range controllable transformer (1), and the other end is connected with the first filter inductor (L)f1) Connecting;
one end of the fourth filter capacitor (7) and the first filter inductor (L)f1) Connected to the other end of said second filter inductor (L)f2) Connecting;
one side of the input voltage transformer (8) is connected with a primary side input voltage main circuit of the wide-range controllable transformer (1), and a voltage signal output end (V) of the input voltage transformer (8)ain) The voltage signal input port of the measurement and control module (2) is connected with the voltage signal input port;
one side of the output voltage transformer (9) is connected with the main circuit of the secondary output voltage of the wide-range controllable transformer (1), and the voltage signal output end (V) of the output voltage transformer (9)aout) The voltage signal input port of the measurement and control module (2) is connected with the voltage signal input port;
the output current transformer (10) is connected in series in an output main circuit of the wide-range controllable transformer (1), and a current signal output end (I) of the output current transformeraout) The current signal input port of the measurement and control module (2) is connected with the current signal input port of the measurement and control module;
the output end of the control signal of the measurement and control module (2) is respectively connected with the first group of power tubes (S) of the first power unit (3)1) And a second group of power tubes (S)2) A control terminal of the second power unit (4), a third group of power tubes (S)3) And a fourth group of power tubes (S)4) And said first bidirectional thyristor (S)a1) A second bidirectional thyristor (S)a2) A third bidirectional thyristor (S)a3) And a fourth bidirectional thyristor (S)a4) The input end of the measurement and control module (2) is connected with the output end of the voltage and current measurement device, and the measurement and control module (2) is connected with an upper computer.
2. The grid power oscillation suppressor of claim 1, characterized in that the measurement and control module (2) is a digital signal processor, a single-chip microcomputer or a computer.
3. Grid power oscillation suppressor according to claim 1, characterized in that said first set of power transistors (S)1) A second group of power tubes (S)2) And a third group of power tubes (S)3) And a fourth group of power tubes (S)4) Integrated Gate Commutated Thyristors (IGCTs), gate turn-on thyristors (GTOs), metal-oxide-semiconductor field effect transistors (MOSFETs) or other power electronic switches.
4. Grid power oscillation suppressor according to claim 1, characterized in that
Phase A: the cross phase conversion module (5) is composed of NV (network video) in which C phases are connected in seriescinNV with windings and B phases connected in seriesbinWinding and first bidirectional thyristor (S)a1) A second bidirectional thyristor (S)a2) A third bidirectional thyristor (S)a3) And a fourth bidirectional thyristor (S)a4) The first bidirectional thyristor (S)a1) And said first filter inductance (L)f1) Is connected with the other end of the first bidirectional thyristor (S)a1) And the other end of (3) and said C-phase NVcinThe winding negative tap (11) is connected, the C phase NVcinPositive tap of winding and said B-phase NVbinNegative tap of winding, the B-phase NVbinPositive tap of winding and said third bidirectional thyristor (S)a3) Is connected to one end of the third bidirectional thyristor (S)a3) And the other end of the first power unit (4) and a third power tube (S) of the second power unit (4)3) The input ends of the two are connected; the second bidirectional thyristor (S)a2) And said first bidirectional thyristor (S)a1) One end connected to the second bidirectional thyristor (S)a2) And the other end of said third bidirectional thyristor (S)a3) One end of the two ends are connected; the fourth bidirectional thyristor (S)a4) And said first bidirectional thyristor (S)a1) Is connected to the other end of the first bidirectional thyristor (S)a1) And the other end of said third bidirectional thyristor (S)a3) The other ends of the two are connected;
phase B: the cross phase conversion module (5) is composed of NV (network video) in which A phases are connected in seriesainNV with windings and C-phase seriescinWinding and first bidirectional thyristor (S)a1) A second bidirectional thyristor (S)a2) A third bidirectional thyristor (S)a3) And a fourth bidirectional thyristor (S)a4) The first bidirectional thyristor (S)a1) And said first filter inductance (L)f1) Is connected with the other end of the first bidirectional thyristor (S)a1) And the other end of said phase A NVainThe winding negative tap (11) is connected, the A phase NVAinPositive tap of winding and said C-phase NVcinNegative tap of winding, the C phase NVcinPositive tap of winding and said third bidirectional thyristor (S)a3) Is connected to one end of the third bidirectional thyristor (S)a3) And the other end of the first power unit (4) and a third power tube (S) of the second power unit (4)3) The input ends of the two are connected; the second bidirectional thyristor (S)a2) And said first bidirectional thyristor (S)a1) One end connected to the second bidirectional thyristor (S)a2) And the other end of said third bidirectional thyristor (S)a3) One end of the two ends are connected; the fourth bidirectional thyristor (S)a4) And said first bidirectional thyristor (S)a1) Is connected to the other end of the first bidirectional thyristor (S)a1) And the other end of said third bidirectional thyristor (S)a3) The other ends of the two are connected;
and C phase: the cross phase conversion module (5) is composed of NV (network video) in which B phases are connected in seriesbinNV with windings and A phase in seriesainWinding and first bidirectional thyristor (S)a1) A second bidirectional thyristor (S)a2) A third bidirectional thyristor (S)a3) And a fourth bidirectional thyristor (S)a4) The first bidirectional thyristor (S)a1) And said first filter inductance (L)f1) Is connected with the other end of the first bidirectional thyristor (S)a1) And the other end of (B) phase NVbinThe winding negative tap (11) is connected, the B phase NVbinPositive tap of winding and said phase A NVainNegative tap of winding, the A-phase NVainPositive tap of winding and said third bidirectional thyristor (S)a3) Is connected to one end of the third bidirectional thyristor (S)a3) And the other end of the first power unit (4) and a third power tube (S) of the second power unit (4)3) The input ends of the two are connected; the second bidirectional thyristor (S)a2) And said first bidirectional thyristor (S)a1) One end connected to the second bidirectional thyristor (S)a2) And the other end of said third bidirectional thyristor (S)a3) One end of the two ends are connected; the fourth bidirectional thyristor (S)a4) And said first bidirectional thyristor (S)a1) Is connected to the other end of the first bi-directionalThyristor (S)a1) And the other end of said third bidirectional thyristor (S)a3) And the other end of the two are connected.
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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102801381A (en) * 2012-08-15 2012-11-28 上海交通大学 Controllable transformer device capable of controlling amplitude and phase angle of voltage individually and control method for same

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102801381A (en) * 2012-08-15 2012-11-28 上海交通大学 Controllable transformer device capable of controlling amplitude and phase angle of voltage individually and control method for same

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