Recognize the emulation test method of flexible direct current non-linear power characteristic
Technical field
The present invention relates to the technical field of electric system, a kind of identification flexible direct current non-linear power characteristic is referred in particular to
Emulation test method.
Background technique
Flexible DC transmission based on wholly-controled device, because its inverter have can independent control active power and idle function
Rate, be not in commutation failure, can to passive power grid power etc. numerous technological merits, therefore in the power system have it is wide
Application prospect.In recent years, with the fast development of large-capacity power electronic device and Advanced Control Techniques, flexible DC transmission
Voltage class and power transmission capacity be increased dramatically, in trunk power transmission network application it is also increasing, as North China electricity
The soft straight asynchronous interconnection engineering etc. in Zhangbei County's flexible DC transmission engineering, southwestern power grid in net.
It is straight with AC network dynamic interaction coupled characteristic, and flexibility with the fast development and application of flexible direct current
Stream with AC network combined hybrid system large disturbances under stability characteristic (quality) and control strategy, have become academia and engineering circles concern
Emphasis and hot spot.It is equipped as power electronics, by factors shadows such as control mode conversion, amplitude limit link constraint, relay protective scheme movements
It rings, when short trouble etc. occurs for power grid, and the large disturbances of change of current busbar voltage significant changes is caused to impact, flexible direct current converter station
Nonlinear change feature will be presented in the active power and reactive power of dynamic interaction between power grid, and therefore forms alternating current-direct current coupling
Cooperation interaction, so that serial-parallel power grid dynamic behaviour and stability are increasingly complex.
Under being impacted due to large disturbances, the active power and reactive power that flexible direct current converter station is exchanged with AC network,
Variation has nonlinear characteristic, it is difficult to obtain its large disturbances power characteristic by analytic method.In order to overcome the above problem, existing China
Patent of invention (107102567A) discloses a kind of emulation test system and test method, comprising: real-time simulator, power module
Characteristic simulation device, flexible direct current control protective unit;Real-time simulator passes through Aurora communication connection power module characteristic mould
Quasi- device;Power module characteristic simulation device connects flexible direct current control protective unit by fiber optic communication mode;Real-time simulation
Device is used to simulate the working condition of AC and DC power grid and flexible DC transmission device, and power module characteristic simulation device is used for mould
The working characteristics of power module in quasi- flexible DC transmission device.Although the above-mentioned flexible direct current control protective unit of capable of testing
Performance, but can not intuitively, clearly investigate the phase between flexible direct current control mode, ac grid voltage and flexible power
Mutual influencing mechanism, to be unfavorable for grasping combined hybrid system characteristic and formulate effective stability contorting measure.
Summary of the invention
For this purpose, technical problem to be solved by the present invention lies in overcome effectively grasp combined hybrid system spy in the prior art
Property and the problem of formulate effective stability contorting measure, a kind of effectively grasp combined hybrid system characteristic to provide and formulate effective
Stability contorting measure identification flexible direct current non-linear power characteristic emulation test method.
In order to solve the above technical problems, a kind of emulation testing side of identification flexible direct current non-linear power characteristic of the invention
Method establishes flexible direct current and AC network combined hybrid system simulation model, makes flexible direct current converter station and AC network Dai Weinan etc.
Valve system is connected, and the flexible direct current converter station is connected with flexible direct current control system;Simulate the AC network Dai Weinan
Equal valve systems built-in potential fell and is promoted as the half period;It is disturbed by applying potential into the AC network Thevenin's equivalence system
It is dynamic, calculated through time-domain-simulation, extract flexible direct current change of current bus voltage amplitude, the active power of flexible direct current converter station output and
The response data of reactive power and the flexible direct current related electric amount inside the control system;It draws and becomes with change of current busbar voltage
The characteristic curves such as the converter station active power of change and reactive power.
In one embodiment of the invention, the side for establishing flexible direct current Yu AC network combined hybrid system simulation model
Method are as follows: establish simulation model using power system simulation software PSD-BPA or electric system simulation synthesizer PSASP.
In one embodiment of the invention, the flexible direct current converter station passes through AC network Thevenin's equivalence internal reactance
It is connected with the AC network Thevenin's equivalence system.
In one embodiment of the invention, the AC network Thevenin's equivalence system built-in potential is Es, andWherein Es0、ΔEsAnd ωsThe respectively described AC network is worn
The valve systems built-in potential such as Wei Nan Steady-state Initial, perturbation amplitude and disturbance angular frequency, tfTo disturb start time.
In one embodiment of the invention, after the completion of the step S4, consider control parameter on characteristic influence.
In one embodiment of the invention, also further consider flexible direct current operation power level to characteristic shadow
It rings.
In one embodiment of the invention, also further consider the operation work of combined hybrid system under AC network varying strength
Condition.
The above technical solution of the present invention has the following advantages over the prior art:
The emulation test method of identification flexible direct current non-linear power characteristic of the present invention is drawn with change of current bus electricity
The characteristic curves such as the converter station active power of buckling and reactive power can intuitively, clearly investigate flexible direct current controlling party
The active power and idle function of formula, controller parameter to flexible direct current change of current bus voltage amplitude and flexible direct current converter station output
The active power and reactive power of the influence of rate and flexible direct current change of current bus voltage amplitude and flexible direct current converter station output
Between the mechanism that influences each other, for grasp combined hybrid system characteristic, formulate effective stability contorting measure, technical support hand be provided
Section.
Detailed description of the invention
In order to make the content of the present invention more clearly understood, it below according to specific embodiments of the present invention and combines
Attached drawing, the present invention is described in further detail, wherein
Fig. 1 is the emulation test method flow chart of present invention identification flexible direct current non-linear power characteristic;
Fig. 2 is flexible direct current of the present invention and AC network combined hybrid system simulation model;
Fig. 3 is the excitation of flexible direct current change of current busbar voltage large disturbances and its alternating current response of the present invention;
Fig. 4 is flexible direct current change of current busbar voltage large disturbances excitation of the present invention and its active and reactive response;
Fig. 5 is the characteristic curve under the fixed active and fixed idle mode of flexible direct current of the present invention;
Fig. 6 is the characteristic curve under the fixed active and constant voltage mode of flexible direct current of the present invention;
Fig. 7 be in FRTS parameter on the characteristic influence of flexible direct current;
Fig. 8 is initial launch power on the characteristic influence of flexible direct current;
Fig. 9 is the operating condition that combined hybrid system typical case runs under AC network varying strength.
Specific embodiment
As depicted in figs. 1 and 2, the present embodiment provides a kind of emulation testing sides for recognizing flexible direct current non-linear power characteristic
Method includes the following steps: step S1: establishing flexible direct current and AC network combined hybrid system simulation model, makes the flexible direct current change of current
It stands and 10 is connected with AC network Thevenin's equivalence system 20, and the flexible direct current converter station 10 and flexible direct current control system phase
Even;Step S2: it simulates 20 built-in potential of AC network Thevenin's equivalence system and falls and promoted as the half period;Step S3: logical
It crosses and applies potential perturbation into the AC network Thevenin's equivalence system 20, calculated through time-domain-simulation, extract flexible direct current and change
Flow bus voltage amplitude, the active power of flexible direct current converter station output and reactive power and the flexible direct current control system
The response data of internal related electric amount;Step S4: the converter station active power changed with change of current busbar voltage and idle is drawn
The characteristic curves such as power.
The emulation test method that flexible direct current non-linear power characteristic is recognized described in the present embodiment, in the step S1, builds
Vertical flexible direct current and AC network combined hybrid system simulation model, it is special to test flexible direct current converter station large disturbances power response
Property, the flexible direct current converter station is connected with AC network Thevenin's equivalence system, and the flexible direct current converter station and flexibility
DC control system is connected, to realize the phase of the flexible direct current control system with the AC network Thevenin's equivalence system
Even;It in the step S2, simulates 20 built-in potential of AC network Thevenin's equivalence system and falls and promoted as the half period, implement
Large disturbances excitation;In the step S3, by applying potential perturbation into the AC network Thevenin's equivalence system 20, through when
Domain simulation calculation extracts flexible direct current change of current bus voltage amplitude, the active power of flexible direct current converter station output and idle function
The response data of rate and the flexible direct current related electric amount inside the control system, thus be conducive to position crucial effect because
Element;In the step S4, the characteristic curves such as the converter station active power changed with change of current busbar voltage and reactive power, energy are drawn
Enough flexible direct current control mode, controller parameters intuitively, clearly investigated are to flexible direct current change of current bus voltage amplitude and flexibility
The influence of the active power and reactive power of DC converter station output and flexible direct current change of current bus voltage amplitude and flexibility are straight
The mechanism that influences each other between the active power and reactive power of converter station output is flowed, to grasp combined hybrid system characteristic, formulation has
The stability contorting measure of effect, provides technical support means.
The method for establishing flexible direct current Yu AC network combined hybrid system simulation model are as follows: soft using electric system simulation
Part PSD-BPA (Power System Analysis Software) or electric system simulation synthesizer PSASP (Power
System Analysis Software Package) simulation model is established, to test flexible direct current converter station large disturbances power
Response characteristic.As shown in Fig. 2, the flexible direct current converter station 10 is exchanged by AC network Thevenin's equivalence internal reactance with described
Power grid Thevenin's equivalence system 20 is connected, to be conducive to test flexible direct current converter station large disturbances power response characteristic.
20 built-in potential of AC network Thevenin's equivalence system is Es, andWherein Es0、ΔEsAnd ωsThe respectively described AC network is worn
20 built-in potential Steady-state Initial of the valve systems such as Wei Nan, perturbation amplitude and disturbance angular frequency, tfTo disturb start time.
It how is described in detail below by the 20 built-in potential Es of AC network Thevenin's equivalence system positioning crucial effect
Factor.As Δ Es=1.0pu, ωs=0.3927rad/s, tfThe change of current busbar voltage U of=1.0ssSubstantially fall and is disturbed with what is gone up
Dynamic excitation, the d axis of VSC output and the large disturbances transient response of q shaft current are as shown in figure 3, so that it is determined that large disturbances motivate and soft
The dq axis component of property DC converter alternating current, wherein VSC generallys use the bicyclic solution for having outer ring and inner ring double-layer structure
Coupling controller, in addition, also needing the rings such as analog voltage, current limit and fault traversing strategy towards VSC-HVDC Practical Project
Section and the functions such as over-voltage and overcurrent protection;As Δ Es=1.0pu, ωs=0.3927rad/s, tfThe change of current bus of=1.0s
Voltage UsSubstantially fall and is motivated with the disturbance gone up, active power that flexible direct current inverter is absorbed from AC network and idle
Power is as shown in Fig. 4, so that it is determined that the active and reactive power that flexible direct current inverter is exchanged with AC network;Using disturbing greatly
Dynamic advocate approach, the flexible direct current of acquisition is fixed active and determines the U under idle control modes-PcAnd Us-QcCharacteristic curve, such as attached drawing 5
It is shown, so that it is determined that U under the fixed active and fixed idle control mode of flexible direct currents-PcAnd Us-QcCharacteristic curve;Swashed using large disturbances
Method is encouraged, the U under the fixed active and constant voltage control mode of flexible direct current of acquisition is recognizeds-PcAnd Us-QcCharacteristic curve, such as attached drawing 6
It is shown, so that it is determined that U under the fixed active and constant voltage control mode of flexible direct currents-PcAnd Us-QcCharacteristic curve.
In addition, flexible direct current inverter is using fixed active PcSurely idle QcControl mode, reference value PcrefAnd QcrefRespectively
For 1250MW and 200MVar, relevant parameter value is U in fault traversing logicsL1=0.8pu, UsL2=0.5pu, UsH=
0.7pu、IcdF=0.6pu, Icuplim=1.0pu/s.In corresponding company Es, Δ Es=1.0pu, ωs=0.3927rad/s, tf=
The change of current busbar voltage U of 1.0ssLarge disturbances excitation, the active P that flexible direct current is exchanged with AC networkcWith idle QcCharacteristic it is bent
Line Us-PcAnd Us-QcAs shown in Fig. 6.
After the completion of the step S4, consider control parameter on characteristic influence.Specifically, also it is further contemplated that control
Parameter processed is to characteristic curve Us-PcAnd Us-QcInfluence.I in corresponding FRTScdFValue is 3 kinds of 0.6pu, 0.5pu and 0.4pu
Situation, Us-PcAnd Us-QcCorrelation curve it is as shown in Figure 7.As can be seen that in Us<UsL2Subnormal voltage operation section, reduce IcdF
Value can accordingly reduce PcIt is horizontal.In addition, reducing IcdFIdentical P can be promotedcCorresponding working voltage Us。
Also further consider flexible direct current operation power level on characteristic influence.Specifically, corresponding initial launch
Power is 3 kinds of situations of 100%, 80% and 50% rated power PN, Us-PcAnd Us-QcCorrelation curve it is as shown in Figure 8.From figure
8 as can be seen that in Us<UsL2Subnormal voltage operation section in, reduce initial launch power can accordingly reduce PcIt is horizontal.In addition, subtracting
Small initial launch power can promote identical PcCorresponding working voltage Us。
Also further consider the operating condition of combined hybrid system under AC network varying strength.Specifically, passing through large disturbances
On the basis of advocate approach obtains flexible direct current non-linear power characteristic, i.e., in combination with AC network power transfer characteristic, analysis is handed over
Direct current combined hybrid system large disturbance stability.Fig. 9 show varying strength AC network power transfer characteristic curve U after failures-Ps
With flexible direct current power characteristic Us-PcIntersection point situation, i.e. stable operating point situation after alternating current-direct current combined hybrid system large disturbances,
Correspondence analysis serial-parallel power grid stability characteristic (quality) and corresponding control strategy can be formulated according to post-fault stable operating point, wherein 1.-
4. for AC network U under varying strengths-PsCharacteristic curve.
Obviously, the above embodiments are merely examples for clarifying the description, does not limit the embodiments.For
For those of ordinary skill in the art, other different form variations can also be made on the basis of the above description or are become
It is dynamic.There is no necessity and possibility to exhaust all the enbodiments.And obvious variation extended from this or change
It moves still within the protection scope of the invention.