| Electric energy is the cornerstone of modern social development,and its relevant data can be regarded as the “barometer”of national economic and social development.Smart grid,as the main carrier of electricity,highly integrates advanced technologies in the fields of information,communication and control with the physical grid,which can optimize resource allocation and the relationship between supply and demand,ensure the safety,reliability,green environmental protection and quality of power supply,thus achieving the purpose of promoting the development of a unified open and ordered competition power market system.Building a resource-saving and environment-friendly society is not only a major strategic decision and strategic initiatives of the communist party of China(CPC),but also an important goal of national development.Building a new green and low-carbon development model is also an important and urgent task that awaits global governors.Line-loss,power loss during transmission,transformation and distribution in physical power grid is not only one of power grid enterprise’s main production costs,but also one of the biggest obstacles to realize green and efficient power supply.With the increase of power load year by year,especially the implementation of ”four services to home” in rural areas of China,the line-loss of middle-low voltage districts(MVDs)is increasing day by day.Effectively mastering and managing the power loss of the power grid in middlelow voltage district(MVD)has become a key breakthrough for power grid enterprises to achieve green and high efficiency.The line-loss of middle-low voltage district(MVD)can usually be calculated based on the real-time measurement data of the smart meter in the district,but it will inevitably lead to a series of data security problems.Relevant studies have shown that the user’s real-time power consumption data will effectively reflect the user’s living habits,economic conditions and other personal privacy information.In addition,the line-loss can also reflect the operation costs,business volume and other relevant sensitive data of different power grid enterprises.In particular,there have been many events to resist the development of smart grid caused by data security and privacy leakage around the world.Therefore,the privacy of users and the security of line loss data during the calculation of line loss in the medium-low voltage district(MVD)have become key issues to be solved urgently in the line loss management of smart grids.From the perspective of the system architecture of smart grid,it is a complex,widely distributed,open and friendly comprehensive system.The traditional security and privacy protection mechanisms can not be directly applied to the data security related problems of the line-loss calculation.It is urgent to create new related mechanisms to solve these problems.Based on the systematic study of smart grid data security and users’ privacy protection,we make an in-depth study on the data security and privacy protection problems emerging in the line-loss calculation of middle-low voltage district(MVD),and gives a solution in three steps.The main works are as follows:1.The protection mechanism of users’ real-time power consumption privacy data in the process of the line-loss calculation in middle-low voltage district(MVD)of the smart grid named EPLC is studied(Chapter 3): In the scheme EPLC,the data measured by a smart meter can real-time,accurately to respond the power consumption of one user who used the smart meter in different periods of time,and each user is located in a middle-low voltage district(MVD)of a high voltage district(HVD).For each user,the scheme EPLC uses two Horner parameters to embed the information of the high and low voltage districts,and encrypts the user’s real-time power consumption data based on the Paillier homomorphic cryptosystem.The gateway of each middle-low voltage district(MVD)calculates the line-loss ciphertext data of the corresponding district under the ciphertext,and the control center(CC)secondary calculates and processes the ciphertext data sent by the gateway to form a ciphertext digital output,It is used to uniformly represent the line-loss in a certain period of time in all middle-low voltage districts(MVDs).All transmission and calculation are carried out in ciphertext.Finally,the line-loss access entity holding the private key and Horner parameters can decrypt and recover the line-loss plaintext of each middle-low voltage district(MVD)in the smart grid.In addition,the scheme EPLC adopts batch verification technology to lower the overhead.Finally,security analysis and simulation experiments show that the scheme EPLC can not only calculate the line-loss efficiently,but also effectively protect the privacy of users.The flexibility and scalability of the scheme EPLC are also very suitable for smart grid scene.2.Alongside the protection of users’ real-time power consumption privacy data,the dynamic and fine-grained distributed access control mechanism of line loss data in different middle-low voltage districts(MVDs)are studied(Chapter 4): The scheme DFACP-LC introduces attribute authorization center(AAC)and key distribution center(KDC)into the system model of the scheme EPLC.According to the encryption strategy defined by the control center(CC),the key distribution center(KDC)uses the EBGN homomorphic encryption system to distribute different or the same encryption public keys to users of different districts,before encryption,two Horner parameters are also used to embed the information of districts.For realizing the access control mechanism,the attribute authorization center(AAC)is responsible for transforming the distributed attribute encryption method(D-ABE)according to the access policy defined by the control center(CC)to encrypt the decryption private keys of different middle-low voltage districts(MVDs)distributed by its corresponding key distribution centers(KDCs).The combination of the two steps can not only protect the privacy of users’ real-time power consumption,but also realize the dynamic,fine-grained and distributed access control of line-loss in different middle-low voltage district(MVD).According to the analysis,DFACPLC is the first work to consider and solve these two problems simultaneously in line-loss calculation of smart grid.3.We also studies the query scheme KSAE-L(Chapter 5)for big amount of ciphertext data of line-loss in all middle-low voltage districts(MVDs)of smart grid: In large-scale smart grid environment,the amount of line-loss data was getting larger,query has become one of the primary functions required by each entity that requires access to line-loss of middle-low voltage districts(MVDs)to implement business needs.In order to solve this problem,based on the complete attribute based key policy encryption scheme proposed by Vipul Goyal et al.,we propose an attribute based key policy query encryption scheme(KSAE-L),which realizes fine-grained query control of keyword for line-loss ciphertext of different middle-low voltage districts(MVDs).KSAE-L is superior to some previous schemes on the cloud in terms of computing overhead and access policy expression,and is more suitable for the complex environment of smart grid.KSAE-L not only inherits the relevant advantages of cloud applications,but also realizes efficient and secure keyword query on line-loss ciphertext data.We also provide a detailed performance analysis and security proof for KSAE-L.Experiments also show that KSAE-L is superior to similar work in many aspects.To sum up,we propose a relatively complete system solution to the data security related problems in the line-loss calculation of middle-low voltage district(MVD)for smart grid,in which the security analysis proves the safety and reliability of the solution,while the performance analysis and simulation experiments ensure the feasibility and effectiveness.Although we only take the smart grid architecture as the application background,in fact,our solutions are also applicable to some other similar application scenarios,such as Internet of vehicles,microgrid and so on. |
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