Summary of the invention
The fundamental purpose of the embodiment of the invention is to provide a kind of performance detecting system of photovoltaic generating system, to solve the problem that can't detect the photovoltaic plant performance in the prior art effectively and accurately.
To achieve these goals, the embodiment of the invention provides a kind of performance detecting system of photovoltaic generating system, this system comprises: photovoltaic generating system, current transformer, voltage-tracing device, electric power system model and 380V electric power system, wherein, described photovoltaic generating system is linked into the 380V electric power system via described voltage-tracing device, and the power delivery that described voltage-tracing device produces described photovoltaic generating system is to described 380V electric power system; Described current transformer obtains the current signal of described photovoltaic generating system output, and described current signal is inputed to described electric power system model; Described electric power system model simulation electric circumstance, and export described voltage-tracing device to after the current signal that receives changed into voltage signal; Described voltage-tracing device detects the performance of described photovoltaic plant according to the voltage signal that receives.
Wherein, described voltage-tracing device comprises: the first alternating current-direct current current transformer, the second alternating current-direct current current transformer, DC voltage-stabilizing electric capacity and control section, the described first alternating current-direct current current transformer is connected with described photovoltaic generating system, the described second alternating current-direct current current transformer is connected with described 380V electric power system, the described first alternating current-direct current current transformer is connected by described DC voltage-stabilizing electric capacity with the second alternating current-direct current current transformer, described control section respectively with the described first alternating current-direct current current transformer, the second alternating current-direct current current transformer connects, described control section receives the voltage signal from described electric power system model, and described voltage signal is converted into start pulse signal, with the conducting of controlling each brachium pontis in the described first alternating current-direct current current transformer and the second alternating current-direct current current transformer with end.
Use the three-phase alternating current cable to be connected between described voltage-tracing device and the described 380V electric power system.
Use the three-phase alternating current cable to be connected between described voltage-tracing device and the described photovoltaic generating system.
Use coax signal cable to be connected between described voltage-tracing device and the described electric power system model.
Use coax signal cable to be connected between described current transformer and the described electric power system model.
Described electric power system model is realized by RTDS.
By means of technique scheme, convert voltage signal to behind the electric circumstance of current signal via the electric power system model simulation by photovoltaic generating system and export the voltage-tracing device to, make the voltage-tracing device can detect the performance of photovoltaic generating system according to the voltage signal that receives.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.
Because can't detect the performance of photovoltaic plant at present effectively and accurately, based on this, the embodiment of the invention provides a kind of performance detecting system of photovoltaic generating system, to address the above problem.The present invention is described in detail below in conjunction with accompanying drawing.
Fig. 1 is the structured flowchart of photovoltaic generating system performance detecting system, and as shown in Figure 1, this performance detecting system comprises:
Photovoltaic generating system 1, current transformer 2, voltage-tracing device 3, electric power system model 4 and 380V electric power system 5, wherein, photovoltaic generating system is linked into the 380V electric power system via the voltage-tracing device, and the power delivery that the voltage-tracing device produces photovoltaic generating system is to the 380V electric power system; Current transformer obtains the current signal of photovoltaic generating system output, and current signal is inputed to electric power system model; Electric power system model simulation electric circumstance, and export the voltage-tracing device to after the current signal that receives changed into voltage signal; The voltage-tracing device detects the performance of photovoltaic plant according to the voltage signal that receives.
As seen from the above description, convert voltage signal to behind the electric circumstance of current signal via the electric power system model simulation by photovoltaic generating system and export the voltage-tracing device to, make the voltage-tracing device can detect the performance of photovoltaic generating system according to the voltage signal that receives.
In the specific implementation, can adopt the real-timedigital simulation system, for example RTDS realizes above-mentioned electric power system model.Set up the electric system Equivalent Model by RTDS, be used for the electric circumstance that the simulated light photovoltaic generating system inserts, this electric system Equivalent Model can make up according to the experiment specific requirement.
Particularly, Fig. 2 is the structured flowchart of above-mentioned voltage-tracing device, as shown in Figure 2, voltage-tracing device 3 comprises: the first alternating current-direct current current transformer 31, the second alternating current-direct current current transformer 32, DC voltage-stabilizing electric capacity 33 and control section 34, the first alternating current-direct current current transformer is connected with photovoltaic generating system, the second alternating current-direct current current transformer is connected with the 380V electric power system, the first alternating current-direct current current transformer is connected by DC voltage-stabilizing electric capacity with the second alternating current-direct current current transformer, control section respectively with the first alternating current-direct current current transformer, the second alternating current-direct current current transformer connects, control section receives the voltage signal from electric power system model, and voltage signal is converted into start pulse signal, with the conducting of controlling each brachium pontis in the first alternating current-direct current current transformer and the second alternating current-direct current current transformer with end.
In practical operation, the circuit diagram of voltage-tracing device can be as shown in Figure 3, this device mainly is made of two IGBT alternating current-direct current current transformers, DC voltage-stabilizing electric capacity and control sections, thereby two alternating current-direct current current transformers connect by DC voltage-stabilizing electric capacity photovoltaic generating system side and 380V distribution system top-cross stream voltage is isolated.The voltage signal of photovoltaic generating system top-cross stream voltage-tracing real-time emulation system output.In Fig. 3, the voltage command signal that the control section acceptance of voltage-tracing device is sent by real-timedigital simulation system (RTDS), be converted into the start pulse signal of each brachium pontis of current transformer as calculated, thereby control the conducting of each brachium pontis and end, produce the three-phase alternating voltage of trace command voltage signal at voltage output end, detect the performance of photovoltaic generating system according to the variation of this three-phase alternating voltage, the output of VSG voltage output end namely is three-phase alternating voltage among Fig. 3.
Be connected with the three-phase alternating current cable between above-mentioned 380V electric power system and the voltage-tracing device, electric energy is sent to the 380V electric power system by the voltage-tracing device.Be connected with the three-phase alternating current cable between voltage-tracing device and the photovoltaic generating system, electric energy is sent to the voltage-tracing device by photovoltaic generating system; The current signal that photovoltaic generating system sends to RTDS is by the current transformer collection of installing between photovoltaic generating system and voltage-tracing device and be converted to voltage signal, sends into RTDS through coax signal cable; The voltage command signal that RTDS sends to the voltage-tracing device is taken place by RTDS, sends into the voltage-tracing device through coax signal cable.
Because the capacity of photovoltaic generating system is very little with respect to the practical power systems capacity of its access, therefore concerning photovoltaic generating system, the practical power systems of its access can be regarded a voltage source as, and concerning practical power systems, photovoltaic generating system can be regarded as one to the current source of its injection electric current.Fig. 4 is the synoptic diagram that photovoltaic plant inserts electric power system model, in model, the controllable current source control signal is the current signal of the above-mentioned current transformer photovoltaic generating system output of obtaining, this controllable current source is used at digital simulation model simulated light photovoltaic generating system, this controllable current source control signal is introduced RTDS from actual light photovoltaic generating system outlet CT, the characteristic that can reflect the actual light photovoltaic generating system, the voltage signal that photovoltaic generating system is inserted bus PT in the model is exported from RTDS, sends into the voltage-tracing device.When in RTDS, simulating the various operating mode of electric system (for example line fault, vibration, frequency jitter etc.), namely, when simulating an electric system overall situation for the actual light photovoltaic generating system, the voltage-tracing device is the change in voltage of trace model median generatrix in real time, thereby detects the performance of photovoltaic generating system according to the change in voltage situation.
Particularly, in conjunction with system model shown in Figure 4, the photovoltaic generating system test event can have following several:
1. voltage ripple of power network.That is, the simulated light photovoltaic generating system inserts the voltage fluctuation of bus in electric system, and the voltage-tracing device detects photovoltaic generating system to the accommodation of voltage fluctuation;
2. mains frequency fluctuation.That is, the simulated light photovoltaic generating system inserts the electric voltage frequency fluctuation of bus in electric system, and the voltage-tracing device detects photovoltaic generating system to the accommodation of electric voltage frequency fluctuation;
3. the electrical network three-phase voltage is asymmetric.That is, the voltage of simulated light photovoltaic generating system access bus is asymmetric in electric system, and the voltage-tracing device detects photovoltaic generating system to the asymmetric accommodation of voltage;
4. line voltage falls.That is, the voltage of simulated light photovoltaic generating system access bus falls in electric system, and the voltage-tracing device detects the accommodation that photovoltaic generating system falls voltage.
Below be that example illustrates the embodiment of the invention with detection of grid frequency jitter project.
Photovoltaic generating system, voltage-tracing device, 380V electric power system, real-timedigital simulation system (as RTDS), current transformer are connected as shown in Figure 1, in RTDS, build realistic model as shown in Figure 4, then the electric system part can be built by simplifying electric power system model among Fig. 5 among Fig. 4, genset is exerted oneself and is loaded among adjustment Fig. 5, genset is exerted oneself less than load, then can simulate mains frequency and reduce, raise otherwise can simulate mains frequency.(when mains frequency was 49.9~50.1Hz) variations under the normal condition, photovoltaic generating system should be able to operate as normal in normal range of operation when mains frequency.The test result of voltage-tracing device shows, this photovoltaic generating system can operate as normal when under normal circumstances mains frequency changes between 49.9~50.1Hz, and under the power grid accident situation, when mains frequency fluctuates between 49.5~50.5Hz, this photovoltaic generating system control system is taken measures, not off-grid operation.
As seen from the above description, set up the electric system Equivalent Model by RTDS, be used for simulating the electric circumstance that the actual light photovoltaic generating system inserts, in this model, reflect the temporary of actual photovoltaic generating system with controlled current source, the stable state behavior, the current controling signal of controlled current source is followed the tracks of the actual light photovoltaic generating system and is sent electric current, this model controlled current source is inserted the voltage signal of bus and send into the voltage-tracing device, the interface voltage of this voltage-tracing device and photovoltaic generating system is followed the tracks of the voltage command signal of RTDS, thereby for the photovoltaic generating system real time modelling goes out to insert power system environment, obtain suitable simulated environment by the reference value of adjusting each signal representative then, RTDS, voltage-tracing device and photovoltaic generating system just constitute the closed test environment, and the variation of the voltage that receives by the voltage-tracing device detects the performance of photovoltaic generating system.
The embodiment of the invention can directly be studied at certain actual photovoltaic generating system, the accuracy of emulated data is higher, pass through the embodiment of the invention, can overcome the problem that can't detect the photovoltaic plant performance effectively and accurately of the prior art, thereby can detect the photovoltaic plant performance effectively and accurately, for the research of photovoltaic generating system provides a kind of brand-new means.
One of ordinary skill in the art will appreciate that all or part of step that realizes in above-described embodiment method can instruct relevant hardware to finish by program, this program can be stored in the computer read/write memory medium, such as ROM/RAM, magnetic disc, CD etc.
Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above only is specific embodiments of the invention; and be not intended to limit the scope of the invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.