CN105490281A - Layered and zoned reactive voltage analysis method based on boundary condition - Google Patents

Abstract

The invention belongs to the technical field of grid reactive voltage control, and in particular relates to a layered and partitioned reactive voltage analysis method based on boundary conditions. Including the following steps: layering and partitioning the power grid; determining the research area and its boundary; inputting the maximum and minimum load daily load and generator output, boundary conditions, configuration of reactive power compensation, and regional power grid limits; performing power flow calculations, adjusting Reactive power compensation capacity, adjusting the boundary of the regional power grid to the boundary conditions; judging whether the voltage in the region has exceeded the limit; judging whether the power factor of each main transformer meets the limit value regulations. The present invention can carry out reactive power voltage checking and reactive power voltage optimization at the same time, greatly improves the reactive power voltage analysis efficiency of large-scale power grids, and can carry out key analysis for local power grids, and is suitable for areas with relatively complete regional power grid data but insufficient large-scale power grid data case. It is easy to understand and implement, close to the actual operation of the power grid, and suitable for online applications.

Description

Layered Partitioned Reactive Voltage Analysis Method Based on Boundary Conditions

technical field

The invention belongs to the technical field of grid reactive voltage control, and in particular relates to a layered and partitioned reactive voltage analysis method based on boundary conditions.

Background technique

In the current power system, with the increase of load and the continuous development of various new projects, the operation of the power grid is becoming more and more complicated, and the control of reactive power and voltage is facing various new challenges. In order to ensure the quality of voltage operation, it is necessary to track the changes in the reactive power and voltage of the power grid, carry out timely analysis of the reactive power and voltage of the power grid, and put forward practical decision-making suggestions. Reactive power and voltage analysis has become an indispensable work in the current power grid construction and maintenance process, which is of great significance to the safety, stability and economic operation of the power grid. With the interconnection of large power grids and the continuous expansion of the grid scale, the efficiency of reactive power and voltage analysis needs to be improved urgently.

At present, most of the research on reactive power and voltage control focuses on reactive power optimization, while the research on reactive power and voltage calibration methods is relatively lacking, and the analysis efficiency of large power grids is not high. restricted.

Contents of the invention

In order to overcome the defects existing in the prior art, the present invention provides a layered and partitioned reactive power voltage analysis method based on boundary conditions. A reactive power and voltage analysis method that provides guidance for power grid operation decision-making by carrying out key analysis.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

The stratified and partitioned reactive voltage analysis method based on boundary conditions includes the following steps:

Step 1: Carry out hierarchical partitioning of the grid;

Step 2: Identify the study area and its boundaries;

Step 3: Input the maximum and minimum daily load and generator output, boundary conditions, configuration of reactive power compensation, and regional power grid limits;

Step 4: Perform power flow calculation, adjust reactive power compensation capacity, and adjust the boundary of the regional power grid to the boundary conditions;

Step 5: Determine whether the voltage in the area exceeds the limit;

Step 6: Determine whether the power factor of each main transformer meets the limit value regulations.

The specific method adopted in step 1 is as follows: according to different voltage levels, the same voltage level grid is divided into one layer; In which area is the power supply of a district divided? Substations that are simultaneously powered by different districts are allocated to each district according to the size of the power supply load.

Determining the research area in the step 2, that is, determining the regional power grid to be studied next according to the research needs; the determination of the boundary refers to selecting the substation connected to the power grid in the research area and the upper power grid as the research area borders.

The maximum load day and the minimum load day mentioned in the step 3 respectively refer to the day with the largest load and the day with the smallest load in the year of the regional power grid. This patent uses the maximum load day and the minimum load day as two types of voltage analysis Situation; the input maximum and minimum load daily load and generator output refer to the load of each station in the maximum load day and the output of each generator as a voltage analysis situation to analyze the low voltage problem of the regional power grid; the minimum load The load and output of each generator station in Japan and China are used as a voltage analysis situation to analyze the high voltage problem of the regional power grid; the boundary conditions refer to the voltage and power of the boundary substation of the studied regional power grid on the maximum and minimum load days The factor is used as a boundary condition; the configuration of reactive power compensation refers to the configuration of the total capacity Q _Lmax of the inductive reactive power compensation device in each substation of the power grid under study, and the total capacity Q _Cmax of the configuration of the capacitive reactive power compensation device; the regional power grid limit , refers to the normal operating voltage limit and power factor limit of each station in the regional power grid;

The method of performing power flow calculation described in step 4 includes:

Method 1: The load of each power station is the maximum load daily load, and the output of each generator is the maximum load daily output. Within the range of the total capacity of the reactive power compensation device configuration of each substation, adjust the input reactive power compensation capacity, and the voltage of the boundary substation and The power factor is adjusted to the maximum load daily level, and the voltage of each plant is calculated;

Method 2: The load of each station is the minimum load daily load, and the output of each generator is the minimum load daily output. Within the range of the total capacity of the reactive power compensation device configuration of each substation, adjust the input reactive power compensation capacity, and the voltage of the boundary substation and The power factor is adjusted to the maximum load daily level, and the voltage of each plant and station is calculated.

In the step 5, judging whether the voltage in the region exceeds the limit refers to comparing the voltage calculation result obtained in step 4 with the normal operating voltage limit of each plant input in step 3, and judging whether the voltage calculation result is Existing limit situations include the following methods:

(1) If there is a voltage exceeding the limit, analyze the cause of the voltage exceeding the limit, fine-tune the input reactive power compensation capacity, and re-calculate the voltage; if there is still a substation voltage exceeding the limit, output the substation and the exceeding voltage, and perform The next step; if there is no substation voltage exceeding the limit, proceed to the next step;

(2) If there is no voltage over-limit situation, the voltage in the output area is in good condition, and proceed to the next step.

In the method of judging whether the power factor of each main transformer meets the limit value regulation described in step 6, the power factor of each main transformer is calculated, and the calculation result is compared with the normal operation power factor limit value of each plant station input in step 3 , to judge whether the power factor of each main transformer exceeds the limit;

(1) If there is no case where the power factor of the main transformer exceeds the limit, the power factor of the main transformer in the output area is good;

(2) If there is a situation where the power factor of the main transformer exceeds the limit, output the main transformer and the power factor that exceed the limit, analyze the cause of the limit, and adjust and optimize for the specific reason.

In the step 3: inputting the maximum and minimum load daily load and generator output, boundary conditions, configuration of reactive power compensation, and regional power grid limits means that the power grid information is input into the PSASP simulation software to carry out reactive power and voltage analysis; the PSASP The simulation software is not limited to one kind of simulation calculation software.

In the step 4: the power flow calculation can be performed by various calculation methods such as Newton-Raphson method, Gauss-Seidel method, etc., and is not limited to one power flow calculation method.

Advantage of the present invention and beneficial effect are:

The present invention simplifies the researched power grid by layering and partitioning and equivalence of boundary conditions; by adjusting the input capacity of the existing reactive power compensation, the power flow calculation of the power grid is performed to determine whether the voltage of the substation in the power grid exceeds the limit, and check the existing reactive power compensation equipment Whether the configuration meets the relevant regulations and voltage adjustment needs; optimize the reactive power distribution of the grid by adjusting the power factor of the main transformer to within the specified limit. This method is relatively comprehensive, and can simultaneously perform reactive power voltage calibration and reactive power voltage optimization; and this method uses boundary conditions to equivalently divide large power grids into layers, which greatly improves the efficiency of large-scale power grid reactive power voltage analysis. And it can focus on a local regional power grid in the large power grid to carry out key analysis without modeling the entire network, and is applicable to the situation where the data of the regional power grid is relatively complete, but the data of the large power grid is insufficient. It is easy to understand and implement, close to the actual operation of the power grid, and suitable for online applications.

The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be emphasized that the following description is only exemplary and not intended to limit the scope of the invention and its application.

Description of drawings

Fig. 1 is the flow chart of the present invention's layered and partitioned reactive voltage analysis method based on boundary conditions;

Fig. 2 is a grid wiring diagram provided by an embodiment of the present invention.

detailed description

Example 1:

The present invention is a layered and partitioned reactive voltage analysis method based on boundary conditions, as shown in Figure 1, Figure 1 is a flow chart of the layered and partitioned reactive voltage analysis method based on boundary conditions, the specific operation steps include:

Step 1: Hierarchically partition the grid.

The specific method used in the hierarchical partitioning is: according to different voltage levels, the power grid of the same voltage level is divided into one layer; in the same layer of the power grid, partitions are carried out according to the geographical location and the load power supply range, and the substation is based on which area the power is supplied to In which area it is divided, substations powered by different areas at the same time are allocated to each area according to the size of the power supply load.

Step 2: Identify the study area and its boundaries.

The determination of the research area is to determine the regional power grid to be studied next according to the research needs.

The determination of the boundary refers to selecting the substation connected to the power grid of the research area and the power grid of the upper layer as the boundary of the research area.

Step 3: Input the maximum and minimum daily load and generator output, boundary conditions, configuration of reactive power compensation, and regional power grid limits.

The maximum load day and the minimum load day respectively refer to the day with the largest load and the day with the smallest load in the year of the regional power grid. This patent regards the maximum load day and the minimum load day as two voltage analysis situations.

The daily load and generator output of the maximum and minimum loads of the input refer to the load of each plant station in the maximum load day and the output of each generator as a voltage analysis situation to analyze the low voltage problem of the regional power grid; The load of each plant and the output of each generator are used as a voltage analysis situation to analyze the high voltage problem of the regional power grid.

The boundary conditions refer to taking the voltage and power factor of the boundary substation of the power grid in the research area on the maximum and minimum load days as the boundary conditions.

The configuration of reactive power compensation refers to the total configuration Q _Lmax of inductive reactive power compensation devices and the total configuration Q _Cmax of capacitive reactive power compensation devices of each substation in the power grid under study.

The regional power grid limit refers to the normal operating voltage limit and power factor limit of each station in the regional power grid.

Inputting the above power grid information into various simulation software such as PSASP to carry out reactive power and voltage analysis is not limited to one simulation software.

Step 4: Carry out power flow calculation, adjust reactive power compensation capacity, and adjust regional grid boundary to boundary conditions.

Power flow calculation can be performed in two ways in the PSASP simulation software:

Method 1: The load of each power station is the maximum load daily load, and the output of each generator is the maximum load daily output. Within the range of the total capacity of the reactive power compensation device configuration of each substation, adjust the input reactive power compensation capacity, and the voltage of the boundary substation and The power factor is adjusted to the maximum load daily level, and the voltage of each plant and station is calculated.

Method 2: The load of each station is the minimum load daily load, and the output of each generator is the minimum load daily output. Within the range of the total capacity of the reactive power compensation device configuration of each substation, adjust the input reactive power compensation capacity, and the voltage of the boundary substation and The power factor is adjusted to the maximum load daily level, and the voltage of each plant and station is calculated.

In this step, the power flow calculation method also includes calculation methods such as Newton-Raphson method, Gauss-Seidel calculation method, etc., and is not limited to one power flow calculation method.

Step 5: Determine whether the voltage in the area exceeds the limit.

In the above step 4, after the PSASP power flow calculation, the EACEL table of the voltage calculation results under the two modes of mode 1 and mode 2 can be output, which is convenient for sorting and comparison.

The judging whether the voltage in the area exceeds the limit refers to comparing the voltage calculation result obtained in step 4 with the normal operating voltage limit of each plant input in step 3, and judging whether the voltage calculation result exceeds the limit.

(1) If there is a voltage exceeding the limit, analyze the cause of the voltage exceeding the limit, fine-tune the input reactive power compensation capacity, and re-calculate the power flow in the PSASP software. If there is still a substation voltage exceeding the limit, output the substation and the exceeding voltage, and proceed to the next step; if there is no substation voltage exceeding the limit, proceed to the next step.

(2) If there is no voltage over-limit situation, the voltage in the output area is in good condition, and proceed to the next step.

Step 6: Determine whether the power factor of each main transformer meets the limit value regulations.

In the PSASP software, after performing power flow calculations for the two methods of method 1 and method 2, the power factor of each main transformer can be conveniently output, and the calculation result of the power factor of the main transformer can be compared with the normal operation power factor limit value of each station input in step 3 Compare and judge whether the power factor of each main transformer exceeds the limit value.

(1) If the power factor of the main transformer does not exceed the limit, the power factor of the main transformer in the output area is good.

(2) If there is a situation that the power factor of the main transformer exceeds the limit, output the main transformer and the power factor that exceed the limit, and analyze the cause of the limit. And adjust and optimize for specific reasons.

Example 2:

The content of the present invention will be further described below by taking the 2015 Inner Mongolia Chifeng Power Grid as an embodiment of the present invention.

Firstly, the Chifeng power grid is divided into four layers according to 500kV, 220kV, 66kV, and 10kV; for example, the 66kV level power grid is divided into Zhongjing system, Pingzhuang system, Jinshan system, Chifeng system, Jingouliang system, Lindong system, Tianshan system, Taiben system, Xijiao system, Ningcheng system, hot water system, Wudan system, Daban system, Yuanbaoshan system, Xinhui system, Tongdu system , Chengdong system has 17 areas in total.

The research area is determined to be the 66kV Jinshan system, and the wiring diagram of the power grid in the Jinshan area of Chifeng, Inner Mongolia is shown in Figure 2.

The boundary of this area is determined to be 220kV Jinshan Substation, and the boundary conditions include Jinshan Substation 66kV side voltage and Jinshan Substation high voltage side power factor.

Input the maximum daily load (maximum load) and minimum daily load (minimum load) of each station, as well as the configuration of reactive power compensation devices, as shown in Table 1. There is no power plant in this area, so there is no need to input the daily load and output of the generator set.

Enter the boundary condition value of Jinshan power grid:

(1) Low voltage situation (maximum load day): Jinshan Substation 66kV side voltage is 65.3kV; Jinshan Substation high voltage side power factor is 0.957;

(2) High voltage situation (minimum load day): Jinshan Substation's 66kV side voltage is 67.5kV; Jinshan Substation's high voltage side power factor is 0.991.

Input regional power grid limits include: the normal operation bus voltage of each 66kV substation is controlled between 64.02-70.62kV; the 10kV side bus voltage of each substation is controlled at 10-10.7kV; the power factor of the generator connected to the 66kV power grid can be controlled at 0.8-0.85 ; 66kV main transformer power factor is controlled at 0.9-1; 220kV main transformer power factor is controlled at 0.95-1.

Use the PSASP software to calculate the power flow for both large and small loads, adjust the configured reactive power compensation capacity, and adjust the boundaries of the regional power grid to the boundary conditions.

According to calculations, under the heavy load mode, the 66kV busbar voltage of Wangyedian Substation is as low as 61.4kV, and the 10kV busbar voltage of Xishan Substation is 9.95kV after the capacitor is put in, which are all lower than the lower limit of normal operating voltage; the 10kV busbar of Wangyedian Substation is 10.87kV, Higher than the upper limit of voltage operation. Under the light load mode, the bus voltage of Wangyedian Substation 10kV is 11kV, and that of Niuyingzi Substation 10kV is 10.8kV, both of which are higher than the upper limit of voltage operation.

The main transformer power factors of Wangyedian Substation and Niuyingzi Substation are all lower than 0.9, which do not meet the operation requirements.

1. Reason analysis: Wangyedian substation belongs to the terminal station of the system, with large reactive power load and low load power factor of 0.78, resulting in low voltage problems, and the station is not equipped with reactive power compensation device. After optimizing the load power factor of Wangyedian Substation to 0.9, and compensating the reactive loads of Xiaofu Substation and Shisijiazi Substation on the same line, Wangyedian Substation newly invested 6Mvar capacitors, and the 66kV bus The voltage can be raised to the qualified range.

Moreover, the main transformer ratios of Wangyedian's two sets are inconsistent, which are 63±2×2.5%/11 and 66±2×2.5%/11 respectively. The inconsistency of the transformation ratio leads to the flow of reactive power in the station, which further reduces the power factor of Wangyedian transformation. The two main transformers can be adjusted to the highest gears with similar transformation ratios, namely 1st gear and 3rd gear.

Solution: It is suggested to increase the load power factor and optimize the power factor of Wangyedian transformer to 0.9. At present, Wangyedian station is not equipped with reactive power compensation device. Considering that the station will be relocated and newly built, it is suggested that the new station should be equipped with at least 6Mvar capacitors.

2. Reason analysis: Niuyingzi Substation currently has two main transformers with no-load voltage regulation and a set of 1.2Mvar capacitors. The low load power factor and the inconsistent ratio of the two main transformers lead to the power factor of the main transformer being lower than 0.9. In the size mode, the 10kV bus voltage is difficult to adjust. After calculation, the main transformer tap changer is adjusted to the second gear as the most reasonable operating gear.

Solution: It is suggested to increase the load power factor and optimize the power factor of Niuyingzi Substation to 0.9. Niuyingzi Substation has a plan to relocate and build a new site, and with the increase of load, the problem of high voltage on the 10kV side will be alleviated.

3. Analysis of the reasons: Xishan Substation has difficulty in regulating the voltage of the 10kV busbar. Currently, it is equipped with a 1.5Mvar capacitor. The #1 main transformer has 17 gears in total, with on-load voltage regulation; the #2 main transformer has 5 gears in total, with off-load voltage regulation. . The #1 main transformer is in the 5th gear, and the #2 is in the 1st gear, which is a relatively reasonable operating gear.

Solution: It is recommended to add a 2Mvar capacitor to Xishan Substation.

After the above voltage adjustment, the problem of voltage and main transformer power factor exceeding the limit has been solved, the regional voltage is in good condition, and the distribution of reactive power and voltage has been optimized.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Table 1: Input information table.

Claims (9)

1., based on the layering and zoning reactive voltage analytical method of boundary condition, it is characterized in that: comprise the following steps:

Step 1: layering and zoning is carried out to electrical network;

Step 2: determine institute's survey region and border thereof;

Step 3: input maximum, minimum load daily load and generator output, boundary condition, reactive power compensation configuring condition, regional power grid limit value;

Step 4: carry out Load flow calculation, regulates reactive compensation capacity, regional power grid border is adjusted to boundary condition;

Step 5: in judging area, whether voltage exists out-of-limit situation;

Step 6: judge whether each main transformer power factor meets limit value regulation.

2. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, is characterized in that: the concrete grammar that in described step 1, layering and zoning adopts is: according to different electric pressure layering, same electric pressure electrical network is divided into one deck; In same layer electrical network, carry out subregion according to geographical position and load supply district, which district transformer station is divided according to by which district being powered, and the transformer station of simultaneously being powered by not same district, is assigned in each district by supply load size.

3. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, is characterized in that: determine institute's survey region in described step 2, namely needs the regional power grid determining next will study according to research; Describedly determine border, refer to the transformer station selecting institute's survey region electrical network and be connected with last layer electrical network, as the border of this survey region.

4. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, it is characterized in that: peak day described in described step 3, refer to maximum a day of area power grid load in the middle of a year and minimum one day of load minimum load day respectively, this patent using peak day and minimum load day as two kinds of voltage analysis situations;

Described input is maximum, minimum load daily load and generator output, refers to using the load of Japan-China for peak load each plant stand, each generator output as a kind of voltage analysis situation, analyzed area electrical network low voltage problem; Using the load of Japan-China for minimum load each plant stand, each generator output as a kind of voltage analysis situation, analyzed area electrical network high voltage problem;

Described boundary condition refers to, using institute's survey region electrical network border transformer station in the voltage of maximum, minimum load day and power factor as boundary condition;

Described reactive power compensation configuring condition, refers to and obtains survey region electrical network each transformer station of institute inductive reactive power compensation device configuration total capacity, capacitive reactive power compensation arrangement configuration total capacity;

Described regional power grid restriction, refers to regional power grid each plant stand normal operating voltage limit value, power factor limit value.

5. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, is characterized in that: the mode of carrying out Load flow calculation described in described step 4 comprises:

Mode one: each plant stand load is peak load daily load, each generator output is peak load daily output, within the scope of each Reactive Power Compensation Eqyuipment in Substation configuration total capacity, regulate the reactive compensation capacity dropped into, the voltage of border transformer station and power factor are adjusted to peak day level, calculate each plant stand voltage;

Mode two: each plant stand load is minimum load daily load, each generator output is minimum load daily output, within the scope of each Reactive Power Compensation Eqyuipment in Substation configuration total capacity, regulate the reactive compensation capacity dropped into, the voltage of border transformer station and power factor are adjusted to peak day level, calculate each plant stand voltage.

6. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, it is characterized in that: in judging area described in described step 5, whether voltage exists out-of-limit situation, refer to the voltage result of calculation will obtained in step 4, the each plant stand normal operating voltage limit value inputted with step 3 compares, and judges whether voltage result of calculation exists out-of-limit situation and comprise with under type:

(1) if there is voltage out-of-limit situation, then the out-of-limit reason of analytical voltage, finely tunes the reactive compensation capacity dropped into, and re-starts voltage and calculates; If it is out-of-limit still to there is transformer substation voltage, then exports this transformer station and out-of-limit voltage, carry out next step; If it is out-of-limit to there is not transformer substation voltage, then carry out next step;

(2) if there is not voltage out-of-limit situation, then output area voltage condition is good, carries out next step.

7. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, it is characterized in that: described in described step 6, judge whether each main transformer power factor meets in the mode that limit value specifies, the power factor of each main transformer calculates, each plant stand normal operate power factor limit value result of calculation and step 3 inputted compares, and judges whether each main transformer power factor exists the situation exceeding limit value;

(1) situation that main transformer power factor exceeds limit value if do not exist, then export this region main transformer power factor good;

(2) situation that main transformer power factor exceeds limit value if exist, then export out-of-limit main transformer and out-of-limit power factor, and analyze out-of-limit reason, and carry out adjusting and optimizing for concrete reason.

8. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, it is characterized in that: in described step 3: input maximum, minimum load daily load and generator output, boundary condition, reactive power compensation configuring condition, regional power grid limit value, refers to that electric network information is inputted PSASP simulation software carries out reactive voltage analysis; Described PSASP simulation software is not limited to a kind of simulation calculation software.

9. the layering and zoning reactive voltage analytical method based on boundary condition according to claim 1, it is characterized in that: in described step 4: carrying out Load flow calculation can calculate by the multiple computational methods such as Newton-Raphson approach, gauss seidel method, is not limited to a kind of tidal current computing method.