Distributed photovoltaic acceptance capability assessment method based on transient voltage stability constraint

Abstract

The invention discloses a distributed photovoltaic acceptance capability assessment method based on transient voltage stability constraint, and the method comprises the steps: taking distributed photovoltaic as a research object, and considering an action mechanism of the distributed photovoltaic on the transient voltage stability of a power grid under a transient voltage stability time scale; establishing a low-dimensional voltage stability analysis model of the high-proportion distributed photovoltaic access receiving end power grid by combining the response characteristics of the dynamic elements of the power grid; based on the low-dimensional voltage stability analysis model, analyzing the influence of distributed photovoltaic access on a conventional power supply branch by adopting a branch decoupling method based on power division; and establishing a transient voltage stability analysis quantitative evaluation index, and evaluating the acceptance capability of the distributed photovoltaic system. According to the invention, the limit acceptance capability of distributed photovoltaic under the voltage safety and stability constraint can be comprehensively evaluated.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaic control, and in particular relates to a distributed photovoltaic acceptance capacity evaluation method based on transient voltage stability constraints. Background Art

[0002] With the introduction of the carbon peak and carbon neutrality goals, a large number of distributed photovoltaics are being connected to the distribution network, which has a significant impact on the safe and stable operation of the system. As the penetration rate of distributed photovoltaics continues to increase, it is more difficult for the power grid to ensure the consumption of low power during the lunch break and the supply of peak power in the evening. The power system's information perception and regulation capabilities are insufficient, and existing technical means are difficult to achieve comprehensive "observable, measurable, adjustable, and controllable". The regulation and management system cannot adapt to the development requirements of the new situation, further exacerbating the challenges to the system's dispatching and operation. However, traditional distribution network evaluation indicators can no longer meet actual needs, and it is necessary to consider the acceptance of distributed photovoltaics.

[0003] Domestic and foreign scholars have conducted a lot of research on the evaluation methods of photovoltaic acceptance capacity of distribution networks. However, the research on the photovoltaic acceptance capacity of distribution networks is mostly based on a single or a few factors, which is still imperfect and does not fully consider the influence of factors such as the stability of the system under voltage transient conditions. It is necessary to conduct a comprehensive evaluation of the photovoltaic acceptance capacity of distribution networks. Considering the impact of dynamic (transient) stability, when a large centralized photovoltaic power station is connected, it is necessary to study the impact of various large disturbances on the transient voltage stability of the system, and the possible voltage instability or voltage collapse. Therefore, it is of great significance to use the time domain simulation method to study the transient voltage stability of the system when the system is disconnected and short-circuited, focus on the impact of photovoltaic dynamic characteristics, and explore effective measures to improve the transient voltage stability of the system. Summary of the invention

[0004] The technical problem to be solved by the present invention is to propose a distributed photovoltaic acceptance capacity evaluation method based on transient voltage stability constraints, starting from the reactive power response characteristics of distributed photovoltaics, analyzing the voltage stability instability process and interaction mechanism, extracting the dominant stability characteristics, and constructing a quantitative evaluation index for the voltage of a DC-fed power grid containing a high proportion of distributed photovoltaics.

[0005] The present invention solves the above technical problems with the following solution: A distributed photovoltaic acceptance capacity evaluation method based on transient voltage stability constraints comprises the following steps:

[0006] Taking distributed photovoltaic as the research object, the mechanism of distributed photovoltaic on the transient voltage stability of the power grid is considered under the transient voltage stability time scale; combined with the response characteristics of the dynamic components of the power grid, a low-dimensional voltage stability analysis model is established when a high proportion of distributed photovoltaic is connected to the receiving power grid;

[0007] Based on the low-dimensional voltage stability analysis model, the branch decoupling method based on power shunt is adopted to analyze the impact of distributed photovoltaic access on conventional power supply branches; a quantitative evaluation index for transient voltage stability analysis is established to evaluate the acceptance capacity of distributed photovoltaics.

[0008] The present invention also provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the distributed photovoltaic acceptance capacity assessment method based on transient voltage stability constraints.

[0009] The present invention also provides a computer-readable storage medium on which computer instructions are stored. When the instructions are executed by a processor, the distributed photovoltaic acceptance capacity evaluation method based on transient voltage stability constraints is implemented.

[0010] The beneficial effects of the present invention are as follows: based on the quantitative evaluation index of voltage stability level, the variation law of system voltage stability margin when the operating power, control parameters and other conditions of distributed photovoltaic change under the transient voltage stability time scale is analyzed, and the ultimate acceptance capacity of distributed photovoltaic under the constraints of voltage safety and stability is comprehensively evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is the technical roadmap of the present invention. DETAILED DESCRIPTION

[0012] In order to more clearly and specifically demonstrate the technical content of the present invention, the specific implementation method of the present invention is described in detail below in conjunction with the accompanying drawings and implementation cases.

[0013] like Figure 1 As shown,

[0014] The transient voltage stability of the traditional receiving-end power grid is greatly affected by the dynamic characteristics of the induction motor. When a fault occurs, the electromagnetic power of the induction motor decreases, the mechanical torque drag increases the motor slip, and the induction motor absorbs more reactive power, further reducing the system voltage. If the system dynamic voltage support is insufficient, the induction motor slip continues to increase beyond the critical value, which will lead to instability of the induction motor voltage or even voltage collapse of the entire network. After DC and distributed photovoltaics are connected to the receiving-end power grid: On the one hand, DC and distributed photovoltaics are power electronic devices, and the mechanism of the influence of power electronic control on the voltage stability of the induction motor is unclear. The voltage coupling characteristics of distributed photovoltaic, DC and induction motor loads on different time scales need to be further studied. On the other hand, the active and reactive responses of power electronic devices will change the recovery characteristics of the electromagnetic power of the induction motor. The rapid active power recovery of DC and photovoltaics is conducive to the active balance of the receiving-end power grid, while the too fast active power recovery will also consume reactive power, thereby deteriorating the voltage stability. Therefore, it is necessary to comprehensively consider the recovery characteristics of active and reactive power and analyze the voltage stability characteristics of the AC / DC hybrid receiving-end system under large-scale distributed photovoltaic access.

[0015] The distributed photovoltaic acceptance capacity assessment method based on transient voltage stability constraints includes the following steps:

[0016] Taking distributed photovoltaic as the research object, the mechanism of distributed photovoltaic on the transient voltage stability of the power grid is considered under the transient voltage stability time scale; combined with the response characteristics of the dynamic components of the power grid, a low-dimensional voltage stability analysis model is established when a high proportion of distributed photovoltaic is connected to the receiving power grid;

[0017] Based on the low-dimensional voltage stability analysis model, the branch decoupling method based on power shunt is adopted to analyze the impact of distributed photovoltaic access on conventional power supply branches; a quantitative evaluation index for transient voltage stability analysis is established to evaluate the acceptance capacity of distributed photovoltaics.

[0018] The present invention also provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the distributed photovoltaic acceptance capacity assessment method based on transient voltage stability constraints.

[0019] The present invention also provides a computer-readable storage medium on which computer instructions are stored. When the instructions are executed by a processor, the distributed photovoltaic acceptance capacity evaluation method based on transient voltage stability constraints is implemented.

[0020] The invention described above only expresses the implementation methods of the embodiments of the present invention, and cannot be understood as limiting the scope of the invention patent, nor does it impose any form of limitation on the structure of the embodiments of the present invention. It should be pointed out that for ordinary technicians in this field, several changes and improvements can be made without departing from the concept of the embodiments of the present invention, which all belong to the protection scope of the embodiments of the present invention.

Claims

1. A distributed photovoltaic acceptance capacity assessment method based on transient voltage stability constraints, characterized in that: The following steps are involved: Taking distributed photovoltaic as the research object, the mechanism of distributed photovoltaic on the transient voltage stability of the power grid is considered under the transient voltage stability time scale; combined with the response characteristics of the dynamic components of the power grid, a low-dimensional voltage stability analysis model is established when a high proportion of distributed photovoltaic is connected to the receiving power grid; Based on the low-dimensional voltage stability analysis model, the branch decoupling method based on power shunt is adopted to analyze the impact of distributed photovoltaic access on conventional power supply branches, establish quantitative evaluation indicators for transient voltage stability analysis, and evaluate the acceptance capacity of distributed photovoltaics.

2. An electronic device, comprising: one or more processors; A memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the distributed photovoltaic acceptance capacity assessment method based on transient voltage stability constraints as described in claim 1.

3. A computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the distributed photovoltaic acceptance capacity assessment method based on transient voltage stability constraints as described in claim 1.

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