Microgrid privacy protection method and system based on novel homomorphic encryption algorithm

Abstract

The invention discloses a microgrid privacy protection method and system based on a novel homomorphic encryption algorithm, and relates to the technical field of microgrid control. The method comprises the steps of designing a micro-grid distributed cooperative control method based on a distributed control theory, and realizing frequency recovery of each distributed power supply in a micro-grid; defining a privacy protection connotation and a privacy protection range; according to the defined privacy protection connotation and privacy protection range, a microgrid privacy protection method based on a novel homomorphic encryption algorithm is designed, an initial value and a real-time value of each distributed power supply in the microgrid are protected from being leaked to node neighbors, and the distributed cooperative control target of the microgrid is achieved; and verifying the microgrid privacy protection method based on the novel homomorphic encryption algorithm by using a simulation experiment. According to the invention, the credible perception capability and privacy security of distributed cooperative operation of the micro-grid can be improved.

Description

Technical Field

[0001] The present invention relates to the field of microgrid control technology, and in particular to a microgrid privacy protection method and system based on a novel homomorphic encryption algorithm. Background Art

[0002] With the development of distributed energy technology, more and more distributed energy resources are being developed and connected to the power grid, such as solar energy, wind energy, biomass energy, etc. The access of these distributed energy resource systems can alleviate the dependence of traditional power grids on large power plants, and can also provide power resources in a decentralized manner, thereby improving the reliability and flexibility of power supply.

[0003] However, with the high-density access of renewable energy, the development of wide-area sensing and intelligent control technologies has deepened the information-physical coupling of microgrids, resulting in an increased risk of privacy leakage in microgrids. The stable operation and coordinated control of the system will face new challenges.

[0004] Therefore, it is an urgent problem for technical personnel in this field to propose a microgrid privacy protection method and system based on a new homomorphic encryption algorithm to solve the difficulties existing in the prior art. Summary of the invention

[0005] In view of this, the present invention provides a microgrid privacy protection method and system based on a novel homomorphic encryption algorithm to enhance the trusted perception capability and privacy security of distributed collaborative operation of microgrids.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A microgrid privacy protection method based on a novel homomorphic encryption algorithm includes:

[0008] S1. Based on distributed control theory, a distributed collaborative control method for microgrids is designed to achieve frequency recovery of each distributed power source in the microgrid;

[0009] S2. Define the connotation and scope of privacy protection;

[0010] S3. According to the defined privacy protection connotation and privacy protection scope, a microgrid privacy protection method based on a new homomorphic encryption algorithm is designed to protect the initial value and real-time value of each distributed power source in the microgrid from being leaked to node neighbors, thereby achieving the distributed collaborative control goal of the microgrid;

[0011] S4. Use simulation experiments to verify the microgrid privacy protection method based on the new homomorphic encryption algorithm.

[0012] In the above method, optionally, in S1, a distributed collaborative control method for a microgrid is designed, specifically comprising:

[0013] The expression of microgrid droop control is:

[0014] ω i =ω ni -m pi P i (1)

[0015] Among them, ω i is the output frequency value of distributed power source i, ω ni is the frequency setting of distributed power source i, P i is the output active power value of distributed power source i, m pi is the droop control coefficient of distributed generation i;

[0016] The specific expression of the microgrid frequency restoration target is:

[0017]

[0018] Among them, ω ref is the frequency reference value;

[0019] Based on distributed control theory, the frequency setting value of each distributed power source is only related to its neighbors. The design frequency setting point ω ni To restore the frequency of each distributed power source to the reference value, the frequency setting point ω ni The expression is:

[0020] ω i =ω ni -m pi P i +u ωi +u Pi (3)

[0021] Among them, u ωi and u Pi are the frequency control quantity and active power control quantity of distributed power source i respectively;

[0022] u ωi The specific expression is:

[0023]

[0024] Among them, ω j is the output frequency value of distributed power source j, k ωi is the frequency control gain of distributed power source i, g i is the root frequency gain of distributed power source i, a ij is the connection gain between distributed generation i and distributed generation j, N i is the neighbor set of distributed generation i;

[0025] uPi The specific expression is:

[0026]

[0027] Among them, P j is the output active power value of distributed power source j, m pj is the droop control coefficient of distributed generation j, k Pi is the active power control gain of distributed generation i.

[0028] In the above method, optionally, in S2, the privacy protection connotation and privacy protection scope are defined to protect the data of each distributed power source from being leaked to neighboring nodes during the operation. The privacy protection scope is the true value of the initial value and real-time value of each distributed power source participating in the operation.

[0029] In the above method, optionally, in S3, the initial value and real-time value of each distributed power source in the microgrid are protected from being leaked to node neighbors, and the connection gain a is ij Defined as:

[0030]

[0031] Among them, a i→j ∈Z + and a j→i ∈Z + are the randomly generated unilateral gains of distributed power sources i and j, respectively, + is a set of positive integers, |N i + | and |N i - | are the in-degree and out-degree matrices of distributed generation i, respectively. a and are the minimum and maximum values ​​of the connection gain, respectively. n is the total number of distributed generation sources.

[0032] The above method, optionally, uses P i κ Indicates the data that needs to be encrypted, the new Paillier homomorphic encryption algorithm, specifically including:

[0033] Initialization: ciphertext C used in Paillier homomorphic encryption method i and plaintext P i Is a positive integer. Before applying the encryption method, based on the formula P i =10 κ ·P i κ , P i κ Convert to integer Pi , where k is the number of decimal places retained;

[0034] Public / private key generation: Randomly select two large prime numbers p and q of the same length, satisfying gcd(pq,(p-1)(q-1))=1

[0035] Among them, gcd(·) is the greatest common divisor function;

[0036] Define the public key as The private key is in, lcm(·) is the least common multiple function, It is chosen randomly, but it satisfies in mod is the modulus function; λ = lcm(p-1,q-1);

[0037] Encryption: The ciphertext satisfies Among them, r∈Z + ,0<r<n,E i (·) is the encryption function;

[0038] Decryption: Plaintext satisfies Among them, D i (·) is the decryption function;

[0039] Deinitialization: According to the plaintext P i Derivation of P i κ , the specific expression is:

[0040]

[0041] The above method is optional. The Paillier homomorphic encryption algorithm satisfies the homomorphic addition and homomorphic multiplication characteristics. The specific expression is:

[0042]

[0043] Among them, E i (P i ) τ For E i (P i ) to the power of τ;

[0044] The microgrid privacy protection method based on the new homomorphic encryption algorithm specifically includes:

[0045] S301, for distributed power sources i and j, the connection gain a ij are known to both parties. According to formula (6), a ij Randomly divided into a i→j ∈Z+ and a j→i ∈Z + ;

[0046] S302. Calculate the public key according to the Paillier homomorphic encryption algorithm Private Key Ciphertext E i (ω i (t)), according to formula (8):

[0047] E i (ω i (t)) -1 =E i (-ω i (t)) (9)

[0048] For distributed power source i, the data packet Send it to distributed power j. At the same time, distributed power j encrypts its own frequency value according to the received public key to obtain E i (ω j (t));

[0049] S303, use public key and single-side connection gain a j→i ∈Z + , we get:

[0050] E i (-ω i (t))·E i (ω j (t)) = E i (ω j (t)-ω i (t)),

[0051]

[0052] Transmit formula (10) to distributed power source i, and distributed power source i converts E i (a j→i ·(ω j (t)-ω i (t))) decrypts to a j→i ·(ω j (t)-ω i (t)), and then multiplied by the single-side connection gain a i→j ∈Z + , and we get a i→j ·a j→i ·(ω j (t)-ω i (t)), that is, a ij ·(ω j (t)-ωi (t)), distributed power source i realizes the distributed collaborative operation of microgrid according to the Paillier homomorphic encryption algorithm without knowing the information of distributed power source j.

[0053] In the above method, optionally, in S4, in the simulation experiment, the microgrid is established by the MATLAB toolbox, and the Paillier homomorphic cryptographic algorithm is executed by Python.

[0054] A microgrid privacy protection system based on a novel homomorphic encryption algorithm, performing any of the above-mentioned microgrid privacy protection methods based on a novel homomorphic encryption algorithm, comprising:

[0055] Distributed control module, based on distributed control theory, realizes distributed coordinated control of microgrids;

[0056] Initialization module, converts the transmission data into integers;

[0057] Public key / private key generation module, which generates the public key and private key required for data privacy protection;

[0058] Encryption module, encrypts the transmitted private data;

[0059] Decryption module, decrypting the transmitted private data;

[0060] Deinitialization module, returns the transmission data to the initial state;

[0061] Verification module, uses simulation experiments to verify the proposed method.

[0062] It can be seen from the above technical solution that compared with the prior art, the present invention provides a microgrid privacy protection method and system based on a new homomorphic encryption algorithm, which has the following beneficial effects: based on the traditional homomorphic encryption algorithm, the present invention designs a new homomorphic encryption algorithm to improve the existing privacy protection algorithm, such as low computational efficiency, few computational types, and high storage overhead. In addition, it significantly reduces the computational efficiency and storage overhead, realizes the coordinated operation of microgrids, and protects the privacy data of interactive subjects, thereby promoting the development of privacy-safe microgrids. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0064] Figure 1A flowchart of a microgrid privacy protection method based on a novel homomorphic encryption algorithm provided by the present invention;

[0065] Figure 2 A structural block diagram of a microgrid privacy protection system based on a novel homomorphic encryption algorithm provided by the present invention;

[0066] Figure 3 A schematic diagram of the real frequency and encrypted frequency output by each distributed power source under the microgrid privacy protection method based on the novel homomorphic encryption algorithm in the simulation experiment provided by the present invention;

[0067] Figure 4 A schematic diagram of the real active power and encrypted active power output by each distributed power source under the microgrid privacy protection method based on the novel homomorphic encryption algorithm in the simulation experiment provided by the present invention. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0069] In this application, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0070] Reference Figure 1 As shown, the present invention discloses a microgrid privacy protection method based on a novel homomorphic encryption algorithm, comprising:

[0071] S1. Based on distributed control theory, a distributed collaborative control method for microgrids is designed to achieve frequency recovery of each distributed power source in the microgrid;

[0072] S2. Define the connotation and scope of privacy protection;

[0073] S3. According to the defined privacy protection connotation and privacy protection scope, a microgrid privacy protection method based on a new homomorphic encryption algorithm is designed to protect the initial value and real-time value of each distributed power source in the microgrid from being leaked to node neighbors, thereby achieving the distributed collaborative control goal of the microgrid;

[0074] S4. Use simulation experiments to verify the microgrid privacy protection method based on the new homomorphic encryption algorithm.

[0075] Furthermore, in S1, a distributed collaborative control method for a microgrid is designed, specifically including:

[0076] The expression of microgrid droop control is:

[0077] ω i =ω ni -m pi P i (1)

[0078] Among them, ω i is the output frequency value of distributed power source i, ω ni is the frequency setting of distributed power source i, P i is the output active power value of distributed power source i, m pi is the droop control coefficient of distributed generation i;

[0079] The specific expression of the microgrid frequency restoration target is:

[0080]

[0081] Among them, ω ref is the frequency reference value;

[0082] Design frequency set point ω ni In order to restore the frequency of each distributed power source to the reference value, based on the distributed control theory, the frequency setting value of each distributed power source is only related to its neighbors. The frequency setting point ω is designed. ni To restore the frequency of each distributed power source to the reference value, the frequency setting point ω ni The expression is:

[0083] ω i =ω ni -m pi P i +u ωi +u Pi (3)

[0084] Among them, u ωi and u Pi are the frequency control quantity and active power control quantity of distributed power source i respectively;

[0085] uωi The specific expression is:

[0086]

[0087] Among them, ω j is the output frequency value of distributed power source j, k ωi is the frequency control gain of distributed power source i, g i is the root frequency gain of distributed power source i, a ij is the connection gain between distributed generation i and distributed generation j, N i is the neighbor set of distributed generation i;

[0088] u Pi The specific expression is:

[0089]

[0090] Among them, P j is the output active power value of distributed generation j, m pj is the droop control coefficient of distributed generation j, k Pi is the active power control gain of distributed generation i.

[0091] Furthermore, in S2, the privacy protection connotation and privacy protection scope are defined to protect the data of each distributed power source from being leaked to neighboring nodes during the operation. The privacy protection scope is the actual value of the initial value and real-time value of each distributed power source participating in the operation.

[0092] Define more specific privacy protection connotations and a broader privacy protection scope, protect the initial value and real-time value of each distributed power source from being leaked to node neighbors, and lay the foundation for the design of microgrid privacy protection methods;

[0093] Specifically, eavesdroppers are usually divided into two categories: internal honest but curious eavesdroppers and external malicious eavesdroppers;

[0094] 1) Internal honest but curious eavesdroppers: steal private or sensitive transmission information and try to calculate the initial and real-time status of other DGs, which is not in the interest of the DGs themselves;

[0095] 2) External malicious eavesdroppers: maliciously eavesdrop on private and sensitive messages transmitted on communication links and sensors, tamper with real information and anonymously spread erroneous states, causing the microgrid to enter a dangerous operating state.

[0096] Furthermore, in S3, considering the existing privacy protection methods’ low computational efficiency, few computational types, and high storage overhead, a new homomorphic encryption algorithm is designed, and a microgrid privacy protection method based on the new homomorphic encryption algorithm is proposed to protect the initial value and real-time value of each distributed power source in the microgrid from being leaked to node neighbors. Under this premise, the distributed collaborative control goal of the microgrid is still achieved.

[0097] Taking frequency privacy protection as an example, the core privacy leakage problem in distributed control systems is i The real-time value of is leaked to other neighboring nodes of distributed generation i.

[0098] Therefore, the Paillier homomorphic encryption scheme is used to transmit ω i -ω j The value is encrypted. In this case, ω in (4) can be calculated efficiently. i -ω j , without obtaining ω j The actual value of

[0099] However, there are loopholes in the above information exchange mechanism. Specifically, distributed power j cannot obtain the transmission information of distributed power i, but according to formula (4), the corresponding information of distributed power j can be obtained through the status information ω of distributed power i itself. i 、Decryption resultω i -ω j and edge weight a ij infer;

[0100] In order to more comprehensively solve the above problems, the initial value and real-time value of each distributed power source in the microgrid are protected from being leaked to node neighbors. ij Defined as:

[0101]

[0102] Among them, a i→j ∈Z + and a j→i ∈Z + are the randomly generated unilateral gains of distributed power sources i and j, Z + is a set of positive integers, |N i + | and |N i - | are the in-degree and out-degree matrices of distributed generation i, respectively. a and are the minimum and maximum values ​​of the connection gain, respectively. n is the total number of distributed generation sources.

[0103] Furthermore, using Pi κ Indicates the data that needs to be encrypted, the new Paillier homomorphic encryption algorithm, specifically including:

[0104] Initialization: ciphertext C used in Paillier homomorphic encryption method i and plaintext P i Is a positive integer. Before applying the encryption method, based on the formula P i =10 κ ·P i κ , P i κ Convert to integer P i , where k is the number of decimal places retained;

[0105] Public / private key generation: Randomly select two large prime numbers p and q of the same length, satisfying gcd(pq,(p-1)(q-1))=1

[0106] Among them, gcd(·) is the greatest common divisor function;

[0107] Define the public key as The private key is in, lcm(·) is the least common multiple function, It is chosen randomly, but it satisfies

[0108] in mod is the modulus function; λ = lcm(p-1,q-1);

[0109] Encryption: The ciphertext satisfies Among them, r∈Z + ,0<r<n,E i (·) is the encryption function;

[0110] Decryption: Plaintext satisfies Among them, D i (·) is the decryption function;

[0111] Deinitialization: According to the plaintext P i Derivation of P i κ , the specific expression is:

[0112]

[0113] Furthermore, the Paillier homomorphic encryption algorithm satisfies the homomorphic addition and homomorphic multiplication properties. The specific expression is:

[0114]

[0115] Among them, E i (P i ) τ For E i (P i ) to the power of τ;

[0116] The microgrid privacy protection method based on the new homomorphic encryption algorithm specifically includes:

[0117] S301, for distributed power sources i and j, the connection gain a ij are known to both parties. According to formula (6), a ij Randomly divided into a i→j ∈Z + and a j→i ∈Z + ;

[0118] S302. Calculate the public key according to the Paillier homomorphic encryption algorithm Private Key Ciphertext E i (ω i (t)), according to formula (8):

[0119] E i (ω i (t)) -1 =E i (-ω i (t)) (9)

[0120] For distributed power source i, the data packet Send it to distributed power j. At the same time, distributed power j encrypts its own frequency value according to the received public key to obtain E i (ω j (t));

[0121] S303, use public key and single-side connection gain a j→i ∈Z + , we get:

[0122] E i (-ω i (t))·E i (ω j (t)) = E i (ω j (t)-ω i (t)),

[0123]

[0124] Transmit formula (10) to distributed power source i, and distributed power source i converts Ei (a j→i ·(ω j (t)-ω i (t))) decrypts to a j→i ·(ω j (t)-ω i (t)), and then multiplied by the single-side connection gain a i→j ∈Z + , and we get a i→j ·a j→i ·(ω j (t)-ω i (t)), that is, a ij ·(ω j (t)-ω i (t)), distributed power source i realizes the distributed collaborative operation of microgrid according to the Paillier homomorphic encryption algorithm without knowing the information of distributed power source j.

[0125] Furthermore, in S4, in the simulation experiment, the microgrid is established by the MATLAB toolbox, and the Paillier homomorphic cryptographic algorithm is executed by Python.

[0126] A microgrid privacy protection system based on a novel homomorphic encryption algorithm, performing any of the above-mentioned microgrid privacy protection methods based on a novel homomorphic encryption algorithm, comprising:

[0127] Distributed control module, based on distributed control theory, realizes distributed coordinated control of microgrids;

[0128] Initialization module, converts the transmission data into integers;

[0129] Public key / private key generation module, which generates the public key and private key required for data privacy protection;

[0130] Encryption module, encrypts the transmitted private data;

[0131] Decryption module, decrypting the transmitted private data;

[0132] Deinitialization module, returns the transmission data to the initial state;

[0133] Verification module, uses simulation experiments to verify the proposed method.

[0134] In a specific embodiment, simulation experiments were conducted on a computer equipped with an Intel i7-12700H CPU and 32G RAM, the microgrid was established by MATLAB 2021b / Simulink toolbox, and the Paillier homomorphic cryptographic algorithm was executed by Python3.8.6;

[0135] In order to verify the effectiveness of the proposed microgrid privacy protection method based on the new homomorphic encryption algorithm, the simulation process is designed as follows:

[0136] 1) t = 0s, the microgrid enters the island operation mode;

[0137] 2) t = 1.5s, using microgrid distributed secondary control method;

[0138] 3) t = 4s, load increased by 3kW;

[0139] 4) t = 6s, reduce the load by 3kW.

[0140] The total simulation time is 8s, and the microgrid privacy protection method based on the novel homomorphic encryption algorithm proposed in the present invention is used throughout the simulation.

[0141] Reference Figure 3 As shown, a schematic diagram of the convergence of the plaintext (real data) and ciphertext (encrypted data) of each distributed power frequency under the microgrid privacy protection method based on the novel homomorphic encryption algorithm proposed in the present invention is given; wherein the ciphertext is calculated according to the Paillier homomorphic encryption method, corresponding to the left y-axis; the plaintext corresponds to the right y-axis; the upper half of the convergence diagram is the ciphertext, and the lower half is the plaintext;

[0142] By comparing the upper and lower parts of each subgraph, we can see that the encrypted data of each distributed power source is always different from the real data. In addition, it can be seen that although the real state has converged to the pre-designed reference value, the encrypted value of each distributed power source is still random after arbitrarily selecting positive integers r, p, q. Therefore, the simulation results are consistent with the theoretical analysis, that is, without the private key, the eavesdropper cannot infer the real state of the distributed power source.

[0143] Reference Figure 4 As shown, a schematic diagram of the plaintext and ciphertext of the active power of each distributed power source under the microgrid privacy protection method based on the novel homomorphic encryption algorithm proposed in the present invention is given, and the active power simulation result is consistent with the frequency. Therefore, the microgrid privacy protection method based on the Paillier homomorphic encryption algorithm effectively prevents the leakage of privacy information to eavesdroppers.

[0144] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0145] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A microgrid privacy protection method based on a new homomorphic encryption algorithm, characterized in that: include: S1. Based on distributed control theory, a distributed collaborative control method for microgrids is designed to achieve frequency recovery of each distributed power source in the microgrid; S2. Define the connotation and scope of privacy protection; S3. According to the defined privacy protection connotation and privacy protection scope, a microgrid privacy protection method based on a new homomorphic encryption algorithm is designed to protect the initial value and real-time value of each distributed power source in the microgrid from being leaked to node neighbors, thereby achieving the distributed collaborative control goal of the microgrid; S4. Use simulation experiments to verify the microgrid privacy protection method based on the new homomorphic encryption algorithm.

2. According to a microgrid privacy protection method based on a novel homomorphic encryption algorithm according to claim 1, it is characterized in that: In S1, a distributed collaborative control method for microgrids is designed, including: The expression of microgrid droop control is: oh i =ω ni -m pi P i (1) Among them, ω i is the output frequency value of distributed power source i, ω ni is the frequency setting of distributed power source i, P i is the output active power value of distributed power source i, m pi is the droop control coefficient of distributed generation i; The specific expression of the microgrid frequency restoration target is: Among them, ω re f is the frequency reference value; Based on distributed control theory, the frequency setting value of each distributed power source is only related to its neighbors. The design frequency setting point ω ni To restore the frequency of each distributed power source to the reference value, the frequency setting point ω ni The expression is: oh i =ω ni -m pi P i +u ωi +u Pi (3) Among them, u ωi and u Pi are the frequency control quantity and active power control quantity of distributed power source i respectively; u ωi The specific expression is: Among them, ω j is the output frequency value of distributed power source j, k ωi is the frequency control gain of distributed power source i, g i is the root frequency gain of distributed power source i, a ij is the connection gain between distributed generation i and distributed generation j, N i is the neighbor set of distributed generation i; u Pi The specific expression is: Among them, P j is the output active power value of distributed generation j, m pj is the droop control coefficient of distributed generation j, k Pi is the active power control gain of distributed generation i.

3. According to a microgrid privacy protection method based on a novel homomorphic encryption algorithm according to claim 1, it is characterized in that: In S2, the privacy protection connotation and privacy protection scope are defined to protect the data of each distributed power source from being leaked to neighboring nodes during the operation. The privacy protection scope is the true value of the initial value and real-time value of each distributed power source participating in the operation.

4. A microgrid privacy protection method based on a novel homomorphic encryption algorithm according to claim 1 or 2, characterized in that: In S3, the initial value and real-time value of each distributed power source in the microgrid are protected from being leaked to node neighbors, and the connection gain a ij Defined as: Among them, a i→j ∈Z + and a j→i ∈Z+ are the randomly generated unilateral gains of distributed power sources i and j, respectively, Z + is a set of positive integers, and are the in-degree and out-degree matrices of distributed generation i, a and are the minimum and maximum values ​​of the connection gain, respectively. n is the total number of distributed generation sources.

5. According to a microgrid privacy protection method based on a novel homomorphic encryption algorithm according to claim 4, it is characterized in that: use Indicates the data that needs to be encrypted, the new Paillier homomorphic encryption algorithm, specifically including: Initialization: ciphertext C used in Paillier homomorphic encryption method i and plaintext P i Is a positive integer. Before applying the encryption method, based on the formula Will Convert to integer P i , where k is the number of decimal places retained; Public / private key generation: Randomly select two large prime numbers p and q of the same length, satisfying gcd(pq,(p-1)(q-1))=1 Among them, gcd(·) is the greatest common divisor function; Define the public key as The private key is in, lcm(·) is the least common multiple function, It is chosen randomly, but it satisfies in mod is the modulus function; λ = lcm(p-1,q-1); Encryption: The ciphertext satisfies Where r∈Z + ,0<r<n,E i (·) is the encryption function; Decryption: Plaintext satisfies Among them, D i (·) is the decryption function; Deinitialization: According to the plaintext P i Derivation The specific expression is:

6. According to a microgrid privacy protection method based on a novel homomorphic encryption algorithm according to claim 5, it is characterized in that: The Paillier homomorphic encryption algorithm satisfies the homomorphic addition and homomorphic multiplication properties. The specific expression is: Among them, E i (P i ) τ For E i (P i ) to the power of τ; The microgrid privacy protection method based on the new homomorphic encryption algorithm specifically includes: S301, for distributed power sources i and j, the connection gain a ij are known to both parties. According to formula (6), a ij Randomly divided into a i→j ∈Z + and a j→i ∈Z + ; S302. Calculate the public key according to the Paillier homomorphic encryption algorithm Private Key Ciphertext E i (ω i (t)), according to formula (8): E i (oh i (t)) -1 =E i (-ω i (t) (9) For distributed power source i, the data packet Send it to distributed power j. At the same time, distributed power j encrypts its own frequency value according to the received public key to obtain E i (ω j (t)); S303, use public key and single-side connection gain a j→i ∈Z + , we get: Transmit formula (10) to distributed power source i, and distributed power source i converts E i (a j→i ·(ω j (t)-ω i (t))) decrypts to a j→i ·(ω j (t)-ω i (t)), and then multiplied by the single-side connection gain a i→j ∈Z + , and we get a i→j ·a j→i ·(ω j (t)-ω i (t)), that is, a ij ·(ω j (t)-ω i (t)), distributed power source i realizes the distributed collaborative operation of microgrid according to the Paillier homomorphic encryption algorithm without knowing the information of distributed power source j.

7. According to a microgrid privacy protection method based on a novel homomorphic encryption algorithm according to claim 1, it is characterized in that: In S4, in the simulation experiment, the microgrid is established by the MATLAB toolbox, and the Paillier homomorphic cryptographic algorithm is executed by Python.

8. A microgrid privacy protection system based on a novel homomorphic encryption algorithm, executing a microgrid privacy protection method based on a novel homomorphic encryption algorithm as described in any one of claims 1 to 7, comprising: Distributed control module, based on distributed control theory, realizes distributed coordinated control of microgrids; Initialization module, converts the transmission data into integers; Public key / private key generation module, which generates the public key and private key required for data privacy protection; Encryption module, encrypts the transmitted private data; Decryption module, decrypts the transmitted private data; Deinitialization module, returns the transmission data to the initial state; Verification module, uses simulation experiments to verify the proposed method.

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