A method for improving the reliability of an integrated energy system based on a load shedding strategy

Abstract

The present invention discloses a method for improving the reliability of an integrated energy system based on a load shedding strategy. First, a load shedding plan is designed according to the characteristics of flexible loads; then, the sequential Monte Carlo simulation method is adopted to improve the reliability of the integrated energy system; the flexible loads can be shed and transferred according to the actual situation to ensure the stability of the integrated energy system. The sequential Monte Carlo simulation method is used to simulate the impact of the operation states of each load in the integrated energy system on the whole over time series, so as to obtain the reliability index of the integrated energy system with time series characteristics. The present invention can give full play to the potential of flexible loads and improve the reliability of the integrated energy system.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated energy system reliability, and specifically relates to a method for improving the reliability of an integrated energy system based on a load shedding strategy. Background Art

[0002] Traditional energy supply systems mainly rely on non-renewable fossil energy, leading to increasingly serious environmental problems and low energy utilization efficiency. The integrated energy system breaks the existing mode of independent operation of each energy subsystem and realizes the collaborative optimization among multiple energy systems. However, the integrated energy system has large fluctuations in energy supply and will cause local energy supply shortages under the high load operation pressure. Achieving an improvement in the energy supply reliability level of the integrated energy system is one of the key technologies for the development of the integrated energy system. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for improving the reliability of an integrated energy system based on a load shedding strategy, which can give full play to the potential of flexible loads and improve the reliability of the integrated energy system.

[0004] One technical solution to achieve the above purpose is: a method for improving the reliability of an integrated energy system based on a load shedding strategy. First, design a load shedding plan according to the characteristics of flexible loads; then use the sequential Monte Carlo simulation method to improve the reliability of the integrated energy system;

[0005] Flexible loads can be shed and transferred according to the actual situation to ensure the stability of the integrated energy system, which specifically includes the following steps:

[0006] Step 1: Classify flexible loads, and the classification method is as follows:

[0007] For loads that can be removed with a certain compensation when needed, they are called shedable loads, and their compensation cost is:

[0008]

[0009] where, f cut is the compensation cost of the shedable load; represents the fixed cost; represents the compensation cost per shedable load; represents the 0-1 variable of the shed load; represents the power of the shed load at time t;

[0010] For loads that can be partially or fully transferred to other time periods within the scheduling cycle but with the total amount remaining unchanged, they are called transferable loads, and their compensation cost is:

[0011]

[0012] Among them, f trans represents the compensation cost of the transferable load; Ctrans represents the unit compensation cost; represents the power of the transferable load at time t;

[0013] For the load that can be transferred to other time periods within the scheduling cycle but needs to be shifted as a whole, it is called the shiftable load, and its compensation cost is:

[0014]

[0015] In the formula, f sh represents the compensation cost of the transferable load; C sh represents the compensation cost per unit of the transferable load; and represent the start and end times of the original load; is the power of the original load at time t; t * is the start time of the transferred load; is a 0-1 variable, indicating whether the load is transferred or not at time t;

[0016] Step 2: Develop a load shedding strategy for the flexible load given in Step 1, and the judgment criteria include interruption loss, electrical distance, and load contribution index of the electricity consumption department;

[0017] Step 3: For the load shedding strategy proposed in Step 2, the specific method is:

[0018]

[0019] Among them, α i is the importance coefficient of the i-th block of load; L Cn is the importance factor of the n-th load point, β i is the position reduction coefficient of the i-th block of load; d n is the electrical distance between the n-th load point and the power source, and the electrical distance between adjacent two load points is 1;

[0020] Step 4: Assign weights to the indicators proposed in Step 2 and calculate the weighted comprehensive score:

[0021]

[0022] Among them, X n is the comprehensive score of the n-th load; R i is the weight of the i-th evaluation index; X in is the score of the n-th load on the i-th index;

[0023] The sequential Monte Carlo simulation method is used to simulate the impact of the operating states of various loads in the integrated energy system changing over time series on the whole, so as to obtain the reliability index of the integrated energy system with time series characteristics, including the following steps:

[0024] Step 1: For the components of the integrated energy system, assume that their operating states all conform to the working-failure two-state model. The failure rate and repair rate of the device components in the system are λ and μ respectively, the normal working time of the component is T1, and the failure repair time is T2;

[0025] Step 2: Input the original parameters of the system and perform data initialization, and set the simulation time t = 0;

[0026] Step 3: Obtain T1 of each component. The method is as follows:

[0027]

[0028] Step 4: Select the component with the smallest T1 as the failed component, and accumulate the simulation time t;

[0029] Step 5: Obtain T2 of each component. The method is as follows:

[0030]

[0031] Step 6: Adopt the node marking method to conduct a connectivity analysis on the network;

[0032] Step 7: Conduct a state analysis and load shedding on the subsystem where the faulty equipment is located;

[0033] Step 8: Accumulate the fault time and fault times of the load points, and accumulate the simulation time t;

[0034] Step 9: Calculate the reliability index.

[0035] The method for improving the reliability of the integrated energy system based on the load shedding strategy of the present invention gives full play to the potential of flexible loads in improving reliability, reduces the failure rate of load points in the integrated energy system, reduces the average system outage duration, and improves the operating reliability of the integrated energy system. Description of the Drawings

[0036] Figure 1 It is a schematic flow chart of a method for improving the reliability of an integrated energy system based on a load shedding strategy of the present invention;

[0037] Figure 2 It is a power grid structure diagram for the specific implementation of the present invention;

[0038] Figure 3 It is a flow chart of the Monte Carlo simulation method. Detailed Implementation Modes

[0039] To better understand the technical solution of the present invention, the following provides a detailed description through specific embodiments:

[0040] Please refer to Figure 1 , which is a schematic flowchart of a method for improving the reliability of an integrated energy system based on a load shedding strategy of the present invention.

[0041] Specifically, it includes the following steps:

[0042] S1. When a component of the integrated energy system fails or the output is insufficient, load shedding is performed to ensure normal power supply for the remaining load.

[0043] S101. Classify flexible loads, and the classification method is as follows:

[0044] For loads that can be removed with a certain compensation when needed, they are called load-sheddable loads, and their compensation cost is:

[0045]

[0046] where f cut is the compensation cost of the load-sheddable load; represents the fixed cost; represents the compensation cost per unit of load-sheddable load; represents the 0-1 variable of the load-shedding; represents the power of the load-shedding at time t.

[0047] For loads that can be partially or fully transferred to other time periods within the scheduling cycle but with the total amount remaining unchanged, they are called load-transferable loads, and their compensation cost is:

[0048]

[0049] where f trans represents the compensation cost of the load-transferable load; C trans represents the unit compensation cost; represents the power of the load-transferable load at time t.

[0050] For loads that can be transferred to other time periods within the scheduling cycle but need to be shifted as a whole, they are called load-shiftable loads, and their compensation cost is:

[0051]

[0052] In the formula, f sh represents the compensation cost of the load-transferable load; C sh represents the compensation cost per unit of load-transferable load; and represent the start and end times of the original load; is the power of the original load at time t; t * is the start time of the transferred load; is a 0-1 variable indicating whether the load is transferred or not at time t.

[0053] S102. Formulate a load shedding strategy for the flexible loads given in S101, and the judgment criteria include interruption loss, electrical distance, and load contribution index of the power consumption department.

[0054] S103. For the load shedding strategy proposed in S102, the specific method is as follows:

[0055]

[0056] where α i is the importance coefficient of the i-th load; L Cn is the importance factor of the n-th load point, β i is the location reduction coefficient of the i-th load; d n is the electrical distance between the n-th load point and the power source, and the electrical distance between two adjacent load points is 1.

[0057] S104. Assign weights to the indicators proposed in S102 and calculate the weighted comprehensive score:

[0058]

[0059] where X n is the comprehensive score of the n-th load; R i is the weight of the i-th evaluation indicator; X in is the score of the n-th load on the i-th indicator.

[0060] Figure 2 is the power grid structure diagram in the specific implementation of the present invention, with a total of 39 nodes. The failures of different devices are independent of each other, and only single-fault cases are considered. The fault components include transformers, distribution lines, heat sources, heat pipelines, and energy conversion devices.

[0061] Figure 3 is the flow chart of the Monte Carlo simulation method in the present invention, specifically including the following steps:

[0062] S2. Simulate the impact of the changes in the operating states of each load in the integrated energy system over time series on the whole, so as to obtain the reliability index of the integrated energy system with time series characteristics, specifically including the following steps:

[0063] S201. For the components of the integrated energy system, assume that their working states all conform to the working-failure two-state model. The failure rate and repair rate of the device components in the system are λ and μ respectively. The normal working time of the component is T1, and the failure repair time is T2.

[0064] S202. Input the original parameters of the system and initialize the data, and set the simulation time t = 0.

[0065] S203. Obtain the T1 of each component. The method is as follows:

[0066]

[0067] S204. Select the component with the minimum T1 as the failed component, and accumulate the simulation time t

[0068] S205. Obtain the T2 of each component. The method is as follows:

[0069]

[0070] S206. Use the node marking method to analyze the connectivity of the network.

[0071] S207. Conduct state analysis and load shedding on the subsystem where the faulty device is located.

[0072] S208. Accumulate the failure time and failure times of the load points, and accumulate the simulation time t.

[0073] S209. Calculate the reliability index.

[0074] Those of ordinary skill in the art in this technical field should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention. As long as it is within the scope of the spirit of the present invention, changes and modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A method for improving the reliability of an integrated energy system based on a load shedding strategy, characterized in that, First, design a load shedding scheme according to the characteristics of flexible loads; then, use the sequential Monte Carlo simulation method to improve the reliability of the integrated energy system; Flexible loads can be shed and transferred according to the actual situation to ensure the stability of the integrated energy system. The specific steps are as follows: Step 1: Classify flexible loads. The classification method is as follows: Loads that can be removed with a certain compensation when needed are called shedable loads, and their compensation costs are: Among them, f cut is the compensation cost for the load that can be curtailed; represents the fixed cost; represents the compensation cost per unit of load that can be curtailed; represents the 0-1 variable of the load curtailed; represents the power of the load curtailed at time t; Loads that can be partially or fully transferred to other time periods within the scheduling cycle but with the total amount remaining unchanged are called transferable loads, and their compensation costs are: Among them, f trans represents the compensation cost of the transferable load; Ctrans represents the unit compensation cost; represents the power of the transferable load at time t; Loads that can be transferred to other time periods within the scheduling cycle but need to be shifted as a whole are called shiftable loads, and their compensation costs are: Where, f sh represents the compensation cost of the transferable load; C sh represents the compensation cost per unit of transferable load; and represent the start and end times of the original load; is the power of the original load at time t; t * is the start time of the transferred load; is a 0-1 variable indicating whether the load is transferred or not transferred at time t; Step 2: Develop a load shedding strategy for the flexible loads given in Step 1. The judgment criteria include interruption loss, electrical distance, and the load contribution index of the electricity-consuming department; Step 3: For the load shedding strategy proposed in Step 2, the specific method is: Among them, α i is the importance coefficient of the i-th load block; L Cn is the importance factor of the n-th load point, β i is the location reduction coefficient of the i-th load block; d n is the electrical distance between the n-th load point and the power source, and the electrical distance between two adjacent load points is 1; Step 4: Assign weights to the indicators proposed in Step 2 and calculate the weighted comprehensive score: Among them, X n is the comprehensive score of the nth load; R i is the weight of the ith evaluation index; X in is the score of the ith index of the nth load; The sequential Monte Carlo simulation method is used to simulate the impact of the operating states of each load in the integrated energy system changing over time on the whole, so as to obtain the reliability index of the integrated energy system with time series characteristics. The steps are as follows: Step 1: For the components of the integrated energy system, assume that their operating states all conform to the working-failure two-state model. The failure rate and repair rate of the device components in the system are λ and μ respectively. The normal operating time of the component is T1, and the fault repair time is T2; Step 2: Input the original system parameters and initialize the data, and set the simulation time t = 0; Step 3: Obtain T1 for each component. The method is: Step 4: Select the component with the smallest T1 as the faulty component and accumulate the simulation time t; Step 5: Obtain T2 for each component. The method is: Step 6: Use the node marking method to conduct a connectivity analysis of the network; Step 7: Conduct a state analysis and load shedding for the subsystem where the faulty device is located; Step 8: Accumulate the fault time and fault times of the load points and accumulate the simulation time t; Step 9: Calculate the reliability index.

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