A power grid vibration starting device and vibration starting control method

Abstract

The present invention relates to a power grid oscillation device and oscillation control method, comprising: an oscillation circuit, a first AC interface, a second AC interface and a high-precision measurement system; the impedance and / or current of the power supply object connected is changed by the oscillation circuit, and the system oscillation or resonance is caused at the same time, so as to build system conditions for the stable boundary test of the power supply object; the boundary value of the oscillation of the power supply object is measured, calculated and displayed by the high-precision measurement system. The technology of the present invention can simulate strong and weak power grids and cause system oscillations, and is used to test the response of distributed power sources and microgrids in the oscillation system, and then obtain their ability to adapt to the strength of the power grid and their own stable boundary conditions, which is crucial to improving the adaptability and stability of the equipment under test and reducing the oscillation of the power system with multiple power electronics connected.

Description

Technical Field

[0001] The present invention relates to the field of distributed power supply and microgrid access detection, and in particular to a power grid oscillation device and an oscillation control method. Background Art

[0002] With the rapid development of distributed power sources, distributed energy storage, and microgrids, relevant standards such as requirements and methods for grid access testing have been introduced. Among the testing functions, power frequency withstand voltage test, fault recovery grid connection test, grid connection and off-grid switching test, exchange power control function test, anti-islanding protection function test, power quality test, and reactive power control are routine tests; DC component test, low voltage ride-through test, voltage abnormal response test, and frequency abnormal response test are unconventional tests.

[0003] On the other hand, after the high-density distributed power is connected, it brings or aggravates the problems of voltage over-limit and power quality to the power grid, especially the relatively weak county power grid. Therefore, control technologies such as adaptive grid impedance, active power quality management, and virtual synchronization are applied; distributed power grid-connected equipment and equipment in microgrids are mostly power electronic devices, which are flexible and controllable but have the characteristics of low damping and weak inertia. Due to the excessive system impedance and the mutual coupling between power electronic devices, low-frequency oscillation, high-frequency resonance or divergent instability may occur. Therefore, whether it is the test of new technology application, the ability of distributed power sources and microgrids to adapt to the strength of the power grid, and the determination of the stable boundary of the system connected by multiple distributed power sources and multiple microgrid groups, it is necessary to build an experimental environment based on relevant test equipment for verification. For conventional test items, power frequency withstand voltage testers, leakage current testers, power analyzers, power quality testers, power grid simulators, load disturbances and other devices can meet the requirements, but the test environment constructed by the above detection equipment cannot reproduce the problems of oscillation and resonance under complex working conditions, and cannot test the boundaries of oscillation or divergent instability of the tested equipment or tested system. Summary of the invention

[0004] In view of the deficiencies of the prior art, an object of the present invention is to provide a power grid oscillation device and an oscillation control method, which can cause the power supply object to oscillate by changing the impedance and / or current connected to the power supply object.

[0005] The purpose of the present invention is achieved by adopting the following technical solutions:

[0006] The present invention provides a power grid oscillation device, the improvement of which is that the device comprises: an oscillation circuit, a first AC interface, a second AC interface and a high-precision measurement system;

[0007] One end of the first AC interface is connected to an AC power source, the other end of the first AC interface is connected to one end of the second AC interface through the oscillator circuit, and the other end of the second AC interface is connected to a power supply object of the AC power source;

[0008] The high-precision measurement system is connected to the other end of the first AC interface and one end of the second AC interface respectively through three-phase voltage / current sampling lines;

[0009] The high-precision measurement system is used to collect the voltage / current signal of the power supply object and determine the oscillation condition of the power supply object according to the voltage / current signal.

[0010] Preferably, the power supply object includes: a distributed power source or a microgrid or a small power system.

[0011] Preferably, when the oscillation starting circuit is a passive oscillation starting circuit, the oscillation starting circuit includes:

[0012] a first switch connected between the first AC interface and the second AC interface;

[0013] The connection point between the first switch and the first AC interface is connected to N groups of branches connected in series;

[0014] Each group of branches consists of a reactance and a second switch connected in series in sequence;

[0015] A third switch is connected between the connection point between the reactance and the second switch in each group of branches and the connection point between the first switch and the second AC interface;

[0016] A fourth switch is connected between the end of each group of branches and the connection point between the first switch and the first AC interface;

[0017] The end of the Nth group of branches is also connected to a reactance, a fifth switch and a capacitor connected in series in sequence;

[0018] Wherein, the N is greater than or equal to 2.

[0019] Preferably, when the oscillation starting circuit is an active oscillation starting circuit, the oscillation starting circuit includes:

[0020] a sixth switch connected between the first AC interface and the second AC interface;

[0021] H groups of branches connected in series at both ends of the sixth switch are connected in parallel, each group of branches consisting of a reactance and a seventh switch connected in series in sequence;

[0022] a parallel branch connected between the second AC interface and the sixth switch;

[0023] The parallel branch is composed of an eighth switch and an active converter connected in sequence;

[0024] Wherein, the H is not less than 1.

[0025] Furthermore, the active converter is composed of an LC filter circuit, a three-phase six-arm full-bridge structure, a capacitor and a power supply connected in sequence.

[0026] The present invention provides a vibration control method for the device, wherein the improvement is that the method comprises:

[0027] The passive switch switching scheme is used to control the impedance of the power supply object by controlling the oscillation circuit device until the power supply object oscillates.

[0028] Preferably, the passive switch switching scheme includes:

[0029] A first passive switch switching scheme, wherein the passive switch switching process includes: closing the first switch connected between the first AC interface and the second AC interface, disconnecting the second switch in the N groups of series branches, disconnecting the third switch between the connection point between the reactance and the second switch in the branch and the connection point between the first switch and the second AC interface in the N groups, disconnecting the fourth switch between the end of the N groups of branches and the connection point between the first switch and the first AC interface, and disconnecting the fifth switch connected in series at the end of the N groups of branches;

[0030] A second passive switch switching scheme, wherein the passive switch switching process includes: disconnecting the first switch connected between the first AC interface and the second AC interface, disconnecting the second switch in the N groups of series branches, closing the N groups of third switches connected between the connection point between the reactance and the second switch in the branch and the connection point between the first switch and the second AC interface, closing the N groups of fourth switches between the end of the branch and the connection point between the first switch and the first AC interface, and closing the fifth switch connected in series at the end of the N groups of branches;

[0031] The third passive switch switching scheme, the passive switch switching process includes: disconnecting the first switch between the first AC interface and the second AC interface, disconnecting the second switch connected in each branch from the vth group to the v+ath group, closing the third switch connected between the connection point between the reactance and the second switch in each branch from the vth group to the v+ath group and the connection point between the first switch and the second AC interface, closing the fourth switch between the end of the Nth group of branches and the connection point between the first switch and the first AC interface, and closing the fifth switch connected in series to the end of the Nth group of branches;

[0032] A fourth passive switch switching scheme, wherein the passive switch switching process includes: disconnecting the first switch connected between the first AC interface and the second AC interface, closing the second switch in the N groups of series branches, closing any group of third switches connected between the connection point between the reactance in the branch and the second switch and the connection point between the first switch and the second AC interface, disconnecting the N groups of fourth switches between the end of the branch and the connection point between the first switch and the first AC interface, and closing the fifth switch connected in series at the end of the N groups of branches;

[0033] A fifth passive switch switching scheme, wherein the passive switch switching process includes: closing a first switch connected between the first AC interface and the second AC interface, closing a second switch in N groups of series branches, disconnecting N groups of third switches connected between a connection point between the reactance and the second switch in the branch and a connection point between the first switch and the second AC interface, disconnecting N groups of fourth switches connected between an end of the branch and a connection point between the first switch and the first AC interface, and closing a fifth switch connected in series at the end of the N groups of branches;

[0034] Among them, in the first passive switch switching scheme, the impedance value of the oscillating circuit connected in parallel to the power supply object is 0, and the impedance value of the oscillating circuit connected in series to the power supply object is 0;

[0035] The impedance value of the oscillating circuit connected in parallel to the power supply object in the second passive switch switching scheme is Z1=2πf×L p(N+1) +2πf×C p The impedance of the oscillating circuit connected in series to the power supply object is

[0036] The impedance value of the oscillation circuit connected in parallel to the power supply object in the third passive switch switching scheme is The impedance of the oscillating circuit connected in series with the power supply object is

[0037] In the fourth passive switch switching scheme, the impedance value of the oscillation circuit connected in parallel to the power supply object is The impedance of the oscillating circuit connected in series with the power supply object is

[0038] The impedance value of the oscillation circuit connected in parallel to the power supply object in the fifth passive switch switching scheme is The impedance value of the oscillating circuit connected in series to the power supply object is 0; L pn is the reactance value of the nth group of series-connected branches; f is the operating frequency of the power grid; L p(N+1) C is the reactance value of the resistor connected in series at the end of the Nth group of series branches; pis the capacitance value of the series capacitor at the end of the Nth group of series-connected branches; N is the number of branches connected in series to the power supply object; 2<v+a<N; m∈(1~N).

[0039] The present invention provides a vibration control method based on the device, the improvement of which lies in that the method comprises:

[0040] An active switch switching scheme is used to control the impedance and / or current of the power supply object by the oscillation starting circuit device until the power supply object oscillates.

[0041] Preferably, the active switch switching scheme includes:

[0042] A first active switch switching scheme, wherein the active switch switching process includes: closing a sixth switch connected between the first AC interface and the second AC interface, disconnecting a seventh switch in series with the reactance in each series branch of group H, and disconnecting an eighth switch in series with the active converter in the parallel branch;

[0043] The second active switch switching scheme, the active switch switching process includes: closing the seventh switch connected in series with the reactance in each series branch of the x groups, disconnecting the sixth switch connected between the first AC interface and the second AC interface, and disconnecting the eighth switch connected in series with the active converter in the parallel branch;

[0044] The third active switch switching scheme, the active switch switching process includes: disconnecting the seventh switch connected in series with the reactance in each series branch of group H, closing the sixth switch connected between the first AC interface and the second AC interface, and closing the eighth switch connected in series with the active converter in the parallel branch;

[0045] A fourth active switch switching scheme, wherein the active switch switching process includes: disconnecting a sixth switch connected between the first AC interface and the second AC interface; closing a seventh switch in series with the reactance in each of the x groups of series branches; and closing an eighth switch in series with the active converter in the parallel branch;

[0046] Among them, in the first active switch switching scheme, the impedance value of the series branch of the oscillating circuit connected to the power supply object is 0; the current value of the parallel branch of the oscillating circuit connected to the power supply object is 0;

[0047] The impedance value of the series branch of the oscillation circuit connected to the power supply object in the second active switch switching scheme is The current value of the parallel branch of the oscillation starting circuit connected to the power supply object is 0;

[0048] In the third active switch switching scheme, the impedance value of the series branch of the oscillation circuit connected to the power supply object is 0; the current value of the parallel branch of the oscillation circuit connected to the power supply object is the current value arranged from small to large set by the power grid oscillation device until the power supply object oscillates;

[0049] In the fourth active switch switching scheme, the current value of the parallel branch of the oscillating circuit connected to the power supply object is one of the current values ​​arranged from small to large set by the power grid oscillating device; the impedance value of the series branch of the oscillating circuit connected to the power supply object is x∈(1~H);L gh is the reactance value of the hth group of series branches; f is the operating frequency of the power grid.

[0050] Compared with the closest prior art, the present invention has the following beneficial effects:

[0051] The present invention provides a power grid oscillation device and oscillation control method, which changes the impedance and / or current of the power supply object through an oscillation circuit, and causes system oscillation or resonance, thereby building system conditions for stable boundary testing of the power supply object; and measures, calculates and displays the boundary value of the oscillation of the power supply object through a high-precision measurement system. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a structural diagram of a vibration starting device provided by the present invention;

[0053] Figure 2 It is a structural diagram when the vibration device provided by the present invention is a passive vibration device;

[0054] Figure 3 It is a structural diagram of a second passive switch switching scheme when the oscillating device provided by the present invention is a passive oscillating device;

[0055] Figure 4 It is a structural diagram of a third passive switch switching solution when the oscillating device provided by the present invention is a passive oscillating device;

[0056] Figure 5 It is a structural diagram of a fourth passive switch switching solution when the oscillator device provided by the present invention is a passive oscillator device;

[0057] Figure 6 It is a structural diagram of a fifth passive switch switching solution when the oscillating device provided by the present invention is a passive oscillating device;

[0058] Figure 7 It is a flow chart of a method for testing a boundary value of oscillation generated by a power supply object when the oscillator provided by the present invention is a passive oscillator;

[0059] Figure 8 is a structural diagram when the vibration-generating device provided by the present invention is an active vibration-generating device;

[0060] Fig. 9 It is a flow chart of a method for testing a boundary value of oscillation generated by a powered object when the oscillator provided by the present invention is an active oscillator. DETAILED DESCRIPTION

[0061] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0062] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] The present invention provides a power grid oscillation device, such as Figure 1 As shown, the device includes: an oscillation-starting circuit, a first AC interface, a second AC interface and a high-precision measurement system;

[0064] One end of the first AC interface is connected to an AC power source, the other end of the first AC interface is connected to one end of the second AC interface through the oscillator circuit, and the other end of the second AC interface is connected to a power supply object of the AC power source;

[0065] The high-precision measurement system is connected to the other end of the first AC interface and one end of the second AC interface respectively through three-phase voltage / current sampling lines;

[0066] The high-precision measurement system is used to collect the voltage / current signal of the power supply object and determine the oscillation condition of the power supply object according to the voltage / current signal.

[0067] The power supply object includes: a distributed power source or a microgrid or a small power system.

[0068] In the best embodiment of the present invention, when the oscillating circuit is a passive oscillating circuit, Figure 2 As shown, the oscillation starting circuit includes:

[0069] A first switch K1 connected between the first AC interface and the second AC interface;

[0070] The connection point between the first switch K1 and the first AC interface is connected to N groups of branches connected in series;

[0071] Each group of branches is connected in series with reactance L Pn and the second switch K 2n Composition, including Figure 2 As shown by the reactance L P1 and the second switch K 21 The first branch is connected in series, and the reactance L P2 and the second switch K22 The second branch is connected in series, and the reactance L P3 and the second switch K 23 The third group of branches in series, ..., consists of reactance L PN and the second switch K 2N The Nth group of branches connected in series;

[0072] The reactance L in each branch Pn and the second switch K 2n A third switch K is connected between the connection point between the first switch K1 and the connection point between the second AC interface. 3n , including Figure 2 The reactance L in the first branch is shown P1 and the second switch K 21 A third switch K is connected between the connection point between the first switch K1 and the connection point between the second AC interface. 31 , Reactance L in the second branch P2 and the second switch K 22 A third switch K is connected between the connection point between the first switch K1 and the connection point between the second AC interface. 32 、Reactance L in the third branch P3 and the second switch K 23 A third switch K is connected between the connection point between the first switch K1 and the connection point between the second AC interface. 33 , ..., reactance L in the Nth group of branches PN and the second switch K 2N A third switch K is connected between the connection point between the first switch K1 and the connection point between the second AC interface. 3N ;

[0073] A fourth switch K is connected between the end of each branch and the connection point between the first switch K1 and the first AC interface. 4n , including Figure 2 A fourth switch K is connected between the end of the first group of branches and the connection point between the first switch K1 and the first AC interface. 41 A fourth switch K is connected between the end of the second group of branches and the connection point between the first switch K1 and the first AC interface. 42 A fourth switch K is connected between the end of the Nth group of branches and the connection point between the first switch K1 and the first AC interface. 4N ;

[0074] The end of the Nth group of branches is also connected to the series-connected reactance L P(N+1) , the fifth switch K5 and the capacitor C P ;

[0075] Wherein, the N is greater than or equal to 2.

[0076] In such Figure 2 In the application scenario shown, the present invention provides a method for controlling the vibration of the device, the method comprising:

[0077] The impedance of the power supply object is input by using the oscillation-starting circuit device in the passive switch switching scheme until the power supply object oscillates.

[0078] Preferably, the passive switch switching scheme includes:

[0079] A first passive switch switching scheme, wherein the passive switch switching process includes: closing the first switch K1 connected between the first AC interface and the second AC interface, disconnecting the second switch in the N series branches, disconnecting the third switch between the connection point between the reactance and the second switch in the branch and the connection point between the first switch K1 and the second AC interface in the N series branches, disconnecting the fourth switch between the end of the N series branches and the connection point between the first switch K1 and the first AC interface, and disconnecting the fifth switch K5 connected in series at the end of the N series branches;

[0080] The second passive switch switching solution, such as Figure 3 As shown, the passive switch switching process includes: disconnecting the first switch K1 connected between the first AC interface and the second AC interface, disconnecting the second switch in the N groups of series branches, closing the N groups of third switches connected between the connection point between the reactance and the second switch in the branch and the connection point between the first switch K1 and the second AC interface, closing the N groups of fourth switches between the end of the branch and the connection point between the first switch K1 and the first AC interface, and closing the fifth switch K5 connected in series at the end of the N groups of branches;

[0081] The third passive switch switching solution, such as Figure 4 As shown, the passive switch switching process includes: disconnecting the first switch K1 between the first AC interface and the second AC interface, disconnecting the second switch connected in each branch from the vth group to the v+ath group, closing the third switch connected between the connection point between the reactance and the second switch in each branch from the vth group to the v+ath group and the connection point between the first switch K1 and the second AC interface, closing the fourth switch between the end of the Nth group of branches and the connection point between the first switch K1 and the first AC interface, and closing the fifth switch K5 connected in series to the end of the Nth group of branches;

[0082] The fourth passive switch switching scheme, such as Figure 5As shown, the passive switch switching process includes: disconnecting the first switch K1 connected between the first AC interface and the second AC interface, closing the second switch in the N groups of series branches, closing any third switch between the connection point between the reactance in the branch and the second switch and the connection point between the first switch K1 and the second AC interface, disconnecting the fourth switch between the end of the N groups of branches and the connection point between the first switch K1 and the first AC interface, and closing the fifth switch K5 connected in series at the end of the N groups of branches;

[0083] The fifth passive switch switching scheme, such as Figure 6 As shown, the passive switch switching process includes: closing the first switch K1 connected between the first AC interface and the second AC interface, closing the second switch in the N-group series branch, disconnecting the N-group third switch between the connection point between the reactance and the second switch in the branch and the connection point between the first switch K1 and the second AC interface, disconnecting the N-group fourth switch between the end of the branch and the connection point between the first switch K1 and the first AC interface, and closing the fifth switch K5 connected in series at the end of the N-group branch;

[0084] Among them, in the first passive switch switching scheme, the impedance value of the oscillating circuit connected in parallel to the power supply object is 0, and the impedance value of the oscillating circuit connected in series to the power supply object is 0;

[0085] The impedance value of the oscillating circuit connected in parallel to the power supply object in the second passive switch switching scheme is Z1=2πf×L p(N+1) +2πf×C p The impedance of the oscillating circuit connected in series to the power supply object is

[0086] The impedance value of the oscillation circuit connected in parallel to the power supply object in the third passive switch switching scheme is The impedance of the oscillating circuit connected in series with the power supply object is

[0087] In the fourth passive switch switching scheme, the impedance value of the oscillation circuit connected in parallel to the power supply object is The impedance of the oscillating circuit connected in series with the power supply object is

[0088] The impedance value of the oscillation circuit connected in parallel to the power supply object in the fifth passive switch switching scheme is The impedance value of the oscillating circuit connected in series to the power supply object is 0; L pn is the reactance value of the nth group of series-connected branches; f is the operating frequency of the power grid; L p(N+1) C is the reactance value of the resistor connected in series at the end of the Nth group of series branches; pis the capacitance value of the series capacitor at the end of the Nth group of series-connected branches; N is the number of branches connected in series to the power supply object; 2<v+a<N; m∈(1~N).

[0089] In the embodiment provided by the present invention, the above scheme can be used to test the critical value of the oscillation of the power supply object, such as Figure 7 As shown, including:

[0090] Step 1: Let the passive switch switching scheme with the smallest impedance value among the passive switch switching schemes be i;

[0091] Step 2: Connect the impedance value corresponding to the passive switch switching scheme i to the power supply object, and determine whether the impedance value connected to the power supply object causes oscillation according to the feedback from the high-precision measurement system. If so, output the impedance value connected to the power supply object at this time, and end the operation;

[0092] If not, set i=i+1 and return to step 2 until the powered object oscillates;

[0093] Step 3: The impedance value fed back by the high-precision measurement system when the power supply object generates oscillation is used as the critical value of the power supply object generating oscillation;

[0094] In the best embodiment of the present invention, when the oscillating circuit is an active oscillating circuit, Figure 8 As shown, the oscillation starting circuit includes:

[0095] a sixth switch K6 connected between the first AC interface and the second AC interface;

[0096] H groups of branches connected in series at both ends of the sixth switch K6 are connected in parallel, and each group of branches is connected in series with reactances L gh and the seventh switch K 7h Composition, including Figure 8 As shown by the reactance L g1 and the seventh switch K 71 The first branch is connected in series, and the reactance L g2 and the seventh switch K 72 The second group of branches in series, ..., consists of reactance L gH and the seventh switch K 7H The Hth group of branches connected in series;

[0097] A parallel branch connected between the second AC interface and the sixth switch K6;

[0098] The parallel branch is composed of an eighth switch K8 and an active converter connected in sequence;

[0099] Wherein, the H is not less than 1.

[0100] Specifically, the active converter is composed of an LC filter circuit, a three-phase six-arm full-bridge structure, a capacitor and a power supply connected in sequence.

[0101] In such Figure 8 In the application scenario shown, the present invention provides a method for controlling the vibration of the device, the method comprising:

[0102] The impedance and / or current of the power supply object is input by using the oscillation starting circuit device in the active switch switching scheme until the power supply object oscillates.

[0103] Preferably, the active switch switching scheme includes:

[0104] The first active switch switching scheme, the active switch switching process includes: closing the sixth switch K6 connected between the first AC interface and the second AC interface, disconnecting the seventh switch connected in series with the reactance in each series branch of the H group, and disconnecting the eighth switch K8 connected in series with the active converter in the parallel branch;

[0105] The second active switch switching scheme, the active switch switching process includes: closing the seventh switch connected in series with the reactance in each series branch of the x groups, disconnecting the sixth switch K6 connected between the first AC interface and the second AC interface, and disconnecting the eighth switch K8 connected in series with the active converter in the parallel branch;

[0106] The third active switch switching scheme, the active switch switching process includes: disconnecting the seventh switch connected in series with the reactance in each series branch of group H, closing the sixth switch K6 connected between the first AC interface and the second AC interface, and closing the eighth switch K8 connected in series with the active converter in the parallel branch;

[0107] The fourth active switch switching scheme, the active switch switching process includes: disconnecting the sixth switch K6 connected between the first AC interface and the second AC interface; closing the seventh switch connected in series with the reactance in each series branch of the x group; closing the eighth switch K8 connected in series with the active converter in the parallel branch;

[0108] Among them, in the first active switch switching scheme, the impedance value of the series branch of the oscillating circuit connected to the power supply object is 0; the current value of the parallel branch of the oscillating circuit connected to the power supply object is 0;

[0109] The impedance value of the series branch of the oscillation circuit connected to the power supply object in the second active switch switching scheme is The current value of the parallel branch of the oscillation starting circuit connected to the power supply object is 0;

[0110] In the third active switch switching scheme, the impedance value of the series branch of the oscillation circuit connected to the power supply object is 0; the current value of the parallel branch of the oscillation circuit connected to the power supply object is the current value arranged from small to large set by the power grid oscillation device until the power supply object oscillates;

[0111] In the fourth active switch switching scheme, the current value of the parallel branch of the oscillating circuit connected to the power supply object is one of the current values ​​arranged from small to large set by the power grid oscillating device; the impedance value of the series branch of the oscillating circuit connected to the power supply object is x∈(1~H);L gh is the reactance value of the hth group of series branches; f is the operating frequency of the power grid.

[0112] In the embodiment provided by the present invention, the above scheme can be used to test the critical value of the oscillation of the power supply object, such as Fig. 9 As shown, including:

[0113] Step 1: Let the switching scheme with the smallest impedance value in the active switch switching scheme be r; let the switching scheme with the smallest current value in the active switch switching scheme be y;

[0114] Step 2: Connect the current value corresponding to the active switch switching scheme y or / and the impedance value corresponding to the active switch switching scheme r to the power supply object, and determine whether the impedance value or / and current value connected by the high-precision measurement system causes oscillation in the power supply object. If so, output the impedance value or / and current value connected to the power supply object at this time, and end the operation;

[0115] If not, set r=r+1 or / and y=y+1 and return to step 2; until the powered object oscillates;

[0116] Step 3: The impedance value and / or current value fed back by the high-precision measurement system when the powered object generates oscillation is used as the critical value of the powered object generating oscillation.

[0117] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0118] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0119] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0120] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A power grid oscillation device, characterized in that: The device comprises: an oscillation-starting circuit, a first AC interface, a second AC interface and a high-precision measurement system; One end of the first AC interface is connected to an AC power source, the other end of the first AC interface is connected to one end of the second AC interface through the oscillator circuit, and the other end of the second AC interface is connected to a power supply object of the AC power source; The high-precision measurement system is connected to the other end of the first AC interface and one end of the second AC interface respectively through three-phase voltage / current sampling lines; The high-precision measurement system is used to collect the voltage / current signal of the power supply object and determine the oscillation condition of the power supply object according to the voltage / current signal; When the oscillation circuit is a passive oscillation circuit, the oscillation circuit includes: a first switch connected between the first AC interface and the second AC interface; The connection point between the first switch and the first AC interface is connected to N groups of branches connected in series; Each group of branches consists of a reactance and a second switch connected in series in sequence; A third switch is connected between the connection point between the reactance and the second switch in each group of branches and the connection point between the first switch and the second AC interface; A fourth switch is connected between the end of each group of branches and the connection point between the first switch and the first AC interface; The end of the Nth group of branches is also connected to a reactance, a fifth switch and a capacitor connected in series in sequence; Wherein, N is greater than or equal to 2; When the oscillation circuit is an active oscillation circuit, the oscillation circuit includes: a sixth switch connected between the first AC interface and the second AC interface; H groups of branches connected in series at both ends of the sixth switch are connected in parallel, each group of branches consisting of a reactance and a seventh switch connected in series in sequence; a parallel branch connected between the second AC interface and the sixth switch; The parallel branch is composed of an eighth switch and an active converter connected in sequence; Wherein, H is not less than 1; The power supply object includes: a distributed power source or a microgrid or a small power system.

2. The device according to claim 1, characterized in that The active converter is composed of an LC filter circuit, a three-phase six-arm full-bridge structure, a capacitor and a power supply which are connected in sequence.

3. A vibration control method based on the device according to claim 1, characterized in that: The method comprises: The passive switch switching scheme is used to control the impedance of the power supply object by controlling the oscillation circuit device until the power supply object oscillates.

4. The method according to claim 3, characterized in that The passive switch switching scheme includes: A first passive switch switching scheme, wherein the passive switch switching process includes: closing the first switch connected between the first AC interface and the second AC interface, disconnecting the second switch in the N groups of series branches, disconnecting the third switch between the connection point between the reactance and the second switch in the branch and the connection point between the first switch and the second AC interface in the N groups, disconnecting the fourth switch between the end of the N groups of branches and the connection point between the first switch and the first AC interface, and disconnecting the fifth switch connected in series at the end of the N groups of branches; A second passive switch switching scheme, wherein the passive switch switching process includes: disconnecting the first switch connected between the first AC interface and the second AC interface, disconnecting the second switch in the N groups of series branches, closing the N groups of third switches connected between the connection point between the reactance and the second switch in the branch and the connection point between the first switch and the second AC interface, closing the N groups of fourth switches between the end of the branch and the connection point between the first switch and the first AC interface, and closing the fifth switch connected in series at the end of the N groups of branches; The third passive switch switching scheme, the passive switch switching process includes: disconnecting the first switch between the first AC interface and the second AC interface, disconnecting the second switch connected in each branch from the vth group to the v+ath group, closing the third switch connected between the connection point between the reactance and the second switch in each branch from the vth group to the v+ath group and the connection point between the first switch and the second AC interface, closing the fourth switch between the end of the Nth group of branches and the connection point between the first switch and the first AC interface, and closing the fifth switch connected in series to the end of the Nth group of branches; A fourth passive switch switching scheme, wherein the passive switch switching process includes: disconnecting the first switch connected between the first AC interface and the second AC interface, closing the second switch in the N groups of series branches, closing any group of third switches connected between the connection point between the reactance in the branch and the second switch and the connection point between the first switch and the second AC interface, disconnecting the N groups of fourth switches between the end of the branch and the connection point between the first switch and the first AC interface, and closing the fifth switch connected in series at the end of the N groups of branches; A fifth passive switch switching scheme, wherein the passive switch switching process includes: closing a first switch connected between the first AC interface and the second AC interface, closing a second switch in N groups of series branches, disconnecting N groups of third switches connected between a connection point between the reactance and the second switch in the branch and a connection point between the first switch and the second AC interface, disconnecting N groups of fourth switches connected between an end of the branch and a connection point between the first switch and the first AC interface, and closing a fifth switch connected in series at the end of the N groups of branches; Among them, in the first passive switch switching scheme, the impedance value of the oscillating circuit connected in parallel to the power supply object is 0, and the impedance value of the oscillating circuit connected in series to the power supply object is 0; The impedance value of the oscillating circuit connected in parallel to the power supply object in the second passive switch switching scheme is Z1=2πf×L p(N+1) +2πf×C p The impedance of the oscillating circuit connected in series to the power supply object is The impedance value of the oscillation circuit connected in parallel to the power supply object in the third passive switch switching scheme is The impedance of the oscillating circuit connected in series with the power supply object is In the fourth passive switch switching scheme, the impedance value of the oscillation circuit connected in parallel to the power supply object is The impedance of the oscillating circuit connected in series with the power supply object is The impedance value of the oscillation circuit connected in parallel to the power supply object in the fifth passive switch switching scheme is The impedance value of the oscillating circuit connected in series to the power supply object is 0; L pn is the reactance value of the nth group of series-connected branches; f is the operating frequency of the power grid; L p(N+1) C is the reactance value of the resistor connected in series at the end of the Nth group of series branches; p is the capacitance value of the series capacitor at the end of the Nth group of series-connected branches; N is the number of branches connected in series to the power supply object; 2<v+a<N; m∈(1~N).

5. A vibration control method based on the device according to claim 1 or 2, characterized in that: The method comprises: An active switch switching scheme is used to control the impedance and / or current of the power supply object by the oscillation starting circuit device until the power supply object oscillates.

6. The method according to claim 5, characterized in that The active switch switching scheme includes: A first active switch switching scheme, wherein the active switch switching process includes: closing a sixth switch connected between the first AC interface and the second AC interface, disconnecting a seventh switch in series with the reactance in each series branch of group H, and disconnecting an eighth switch in series with the active converter in the parallel branch; The second active switch switching scheme, the active switch switching process includes: closing the seventh switch connected in series with the reactance in each series branch of the x groups, disconnecting the sixth switch connected between the first AC interface and the second AC interface, and disconnecting the eighth switch connected in series with the active converter in the parallel branch; The third active switch switching scheme, the active switch switching process includes: disconnecting the seventh switch connected in series with the reactance in each series branch of group H, closing the sixth switch connected between the first AC interface and the second AC interface, and closing the eighth switch connected in series with the active converter in the parallel branch; A fourth active switch switching scheme, wherein the active switch switching process includes: disconnecting a sixth switch connected between the first AC interface and the second AC interface; closing a seventh switch in series with the reactance in each of the x groups of series branches; and closing an eighth switch in series with the active converter in the parallel branch; Among them, in the first active switch switching scheme, the impedance value of the series branch of the oscillating circuit connected to the power supply object is 0; the current value of the parallel branch of the oscillating circuit connected to the power supply object is 0; The impedance value of the series branch of the oscillation circuit connected to the power supply object in the second active switch switching scheme is The current value of the parallel branch of the oscillation starting circuit connected to the power supply object is 0; In the third active switch switching scheme, the impedance value of the series branch of the oscillation circuit connected to the power supply object is 0; the current value of the parallel branch of the oscillation circuit connected to the power supply object is the current value arranged from small to large set by the power grid oscillation device until the power supply object oscillates; In the fourth active switch switching scheme, the current value of the parallel branch of the oscillating circuit connected to the power supply object is one of the current values ​​arranged from small to large set by the power grid oscillating device; the impedance value of the series branch of the oscillating circuit connected to the power supply object is x∈(1~H);L gh is the reactance value of the hth group of series branches; f is the operating frequency of the power grid.

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