A communication protocol converter for distribution network material detection system

Abstract

A communication protocol converter for a distribution network material detection system includes a protocol conversion module, a downlink physical interface connected to the protocol conversion module, and an uplink physical interface; the uplink physical interface is used to receive a first detection command issued by a material detection master station, and the first detection command is generated according to a distribution network material detection communication protocol; the protocol conversion module is used to decode the first detection command, and then encapsulate it into a second detection command according to a private communication protocol of a detection instrument manufacturer; the downlink physical interface is used to receive first detection data uploaded by the detection instrument according to the second detection command; the protocol conversion module is also used to decode the first detection data, encapsulate the decoded detection data to generate second detection data and send it to the material detection master station. The present invention can enable existing power detection equipment to seamlessly access the distribution network material detection system, and is widely used for the access of power material detection equipment in the current distribution network material monitoring system, taking into account security, scalability, and ease of implementation.

Description

Technical Field

[0001] The invention relates to the field of power system distribution network material detection, in particular to a communication protocol converter for a distribution network material detection system. Background Art

[0002] In the new power system material detection system, there are various types of detection equipment with different functions and different application subsystems. The communication technology standards are not unified and interoperability is difficult. When the detection equipment is connected to the system, different communication downlink physical interfaces and different communication protocols are used. Many communications are customized by the manufacturer, and the logical level is not clear; the devices cannot communicate with each other. Moreover, a large number of devices belong to closed-loop systems and do not have interfaces to output data to the material detection application system. They must be recorded manually and then manually entered into the material detection system, which reduces work efficiency.

[0003] The reason for these problems is that, on the one hand, the power grid has a careful consideration of network and system security, and secondly, there is no clear specification to guide manufacturers in development, resulting in a large number of new intelligent detection equipment failing to be well connected to the existing material detection system. Therefore, it is necessary to analyze the layered architecture, physical layer, application layer, information security and other aspects of the power grid material detection system, and design a new type of power detection equipment access communication protocol converter for the distribution network material detection system, so that it can be seamlessly connected to the distribution network material detection system. Summary of the invention

[0004] In view of this, the present invention provides a communication protocol converter for a distribution network material detection system to solve the above-mentioned problem.

[0005] A communication protocol converter for a distribution network material detection system, comprising a protocol conversion module, a downlink physical interface connected to the protocol conversion module, and an uplink physical interface;

[0006] The uplink physical interface is used to receive a first detection command issued by the material detection master station, where the first detection command is generated according to the distribution network material detection communication protocol;

[0007] The protocol conversion module is used to decode the first detection command according to the distribution network material detection communication protocol, store it in the buffer, and then encapsulate the content of the decoded first detection command into a second detection command according to the private communication protocol of the detection instrument manufacturer, and send it to the detection instrument through the same downlink physical interface as the detection instrument according to the private communication protocol of the detection instrument manufacturer;

[0008] The downlink physical interface is used to receive first detection data uploaded by the detection instrument according to the second detection command, where the first detection data is generated by the detection instrument after encapsulating the detection data according to a private communication protocol of the detection instrument manufacturer;

[0009] The protocol conversion module is also used to decode the first detection data according to the private communication protocol of the testing instrument manufacturer, save it in a buffer, and then encapsulate the decoded detection data using the distribution network material detection communication protocol to generate second detection data, and then send it to the material detection main station through the Ethernet port. After receiving the second detection data, the material detection main station decodes it according to the distribution network material detection communication protocol to obtain the detection data of the detection instrument.

[0010] Furthermore, the uplink physical interface is an Ethernet interface, which is used to communicate with the material detection main station; the downlink physical interface includes an Ethernet interface, a serial port and a 485 interface, which are used to communicate with the detection instrument.

[0011] Furthermore, the distribution network material detection communication protocol is implemented based on the HTTP protocol, and uses the JSON format as the network data transmission format.

[0012] Furthermore, the communication method of the distribution network material detection communication protocol adopts a request response mode and a timeout retransmission mechanism.

[0013] Furthermore, the material detection main station saves the deviceID number of each protocol converter. When the protocol converter shakes hands with the material detection main station for the first time, if the sending main station checks the handshake message deviceID of the device in its own database, it will generate a random session number sessionID and a random key sessionKey for this session as the credential of this call, and at the same time return the random session number sessionID and the random key sessionkey to the detection instrument, which will be temporarily saved locally. After the protocol converter writes the JSON message of the data content of the message to be sent, it will traverse the JSON structure, obtain the parameter names of all leaf nodes, and sort them in reverse order of the first character to obtain a string set, and save the locally saved JSON message of this session. The sessionKey string is also put into the string set; the strings are concatenated together, and then the shaHmac256 algorithm is used to form a sign, and the value of the sign is attached to the sign field in the message as a verification credential; after receiving the data, the receiving master station first takes out the sessionID in the message, queries the sessionKey corresponding to the temporary sessionID saved locally, and then uses the sessionkey to perform the same encryption operation on the received request data. If it is found that the sign calculated locally is not equal to the sign in the data message, it is considered that the data has been tampered with during communication, otherwise it can be considered that the data is normal, and after data verification and identity authentication, the detection data in the JSON data is obtained and placed in the distribution network material detection database.

[0014] The present invention can enable the existing power detection equipment to be seamlessly connected to the distribution network material detection system, and can be widely used for the access of power material detection equipment in the current distribution network material monitoring system, taking into account safety, scalability and ease of implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the functional hierarchical structure of the distribution network material detection system of the present invention;

[0016] Figure 2 It is a schematic diagram of the communication system architecture of the distribution network material detection system of the present invention;

[0017] Figure 3 It is a working principle diagram of the communication protocol converter used in the distribution network material detection system of the present invention;

[0018] Figure 4 It is a schematic diagram of a request response mode of the communication protocol used by the protocol converter of the present invention;

[0019] Figure 5 It is a schematic diagram of the request message format used by the communication protocol of the present invention;

[0020] Figure 6 It is a schematic diagram of the response message format used by the communication protocol of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0022] See also Figure 1-6 An embodiment of the present invention provides a communication protocol converter for a distribution network material detection system, including a protocol conversion module, a downlink physical interface connected to the protocol conversion module, and an uplink physical interface; the downlink physical interface includes an Ethernet interface, a serial port, and a 485 interface.

[0023] The uplink physical interface is used to receive a first detection command issued by the material detection master station, where the first detection command is generated according to the distribution network material detection communication protocol;

[0024] The protocol conversion module is used to decode the first detection command according to the distribution network material detection communication protocol, store it in the buffer, and then encapsulate it into a second detection command according to the content of the first detection command according to the private communication protocol of the detection instrument manufacturer, and send it to the detection instrument through the same downlink physical interface as the detection instrument according to the private communication protocol of the detection instrument manufacturer;

[0025] The downlink physical interface is used to receive first detection data uploaded by the detection instrument according to the second detection command, where the first detection data is generated by the detection instrument after encapsulating the detection data according to a private communication protocol of the detection instrument manufacturer;

[0026] The protocol conversion module is also used to decode the first detection data according to the private communication protocol of the testing instrument manufacturer, save it in a buffer, and then encapsulate the decoded detection data using the distribution network material detection communication protocol to generate second detection data, and then send it to the material detection main station through the Ethernet port. After receiving the second detection data, the material detection main station decodes it according to the distribution network material detection communication protocol to obtain the detection data of the detection instrument.

[0027] like Figure 1 As shown, the distribution network material detection communication protocol divides the distribution network material detection system into four layers according to the business and function according to the distribution network material workflow and business characteristics: logistics layer (including test layer and logistics system (including AGV logistics robot)), detection instrument layer, communication layer, and centralized control layer. The detection instrument (new detection instrument) is located in the detection instrument layer. Through the more commonly used Internet of Things communication protocol, the inventor of this application found that the HTTP protocol is more suitable for the material detection system connected to the new detection instrument than the MQTT protocol. Therefore, a distribution network material communication based on JSON format and HTTP protocol is designed, and a method for encrypting message data based on shaHmac256 of device ID (deviceID), random session number and random key is designed. Through the above design, the communication protocol for the protocol converter to access the distribution network material detection system (referred to as the distribution network material detection communication protocol) is determined, and then the workflow of the protocol converter is given, and an example of the message is given.

[0028] Figure 1 In the network, fixed-station detection systems and integrated intelligent detection systems can access the backbone network via wired Ethernet, mobile detection systems (internal) can access the backbone network via WIFI, and AGV robots can access the backbone network via WIFI. Mobile detection systems (external) can access the 5G power private network, and then connect to the material detection main network from the gateway.

[0029] The centralized control layer is composed of hardware equipment such as servers and workstations, and the software is composed of database systems, material detection centralized control software, and Web clients.

[0030] There are many types of testing equipment at the material and equipment testing site. Some testing equipment has Ethernet (WIFI, 4G / 5G) communication interface, and some equipment only has original interfaces such as 232 / 485. New intelligent testing equipment can directly provide this communication protocol for manufacturers to develop and connect with the platform. Some equipment manufacturers cannot change or do not have Ethernet communication conditions, or it is inconvenient to change. Therefore, a protocol converter can be used as an intermediary to realize the communication between the testing instrument and the host computer of the material testing system.

[0031] Commonly used IoT protocols are MQTT and HTPP. In the distribution network material detection system, the detection equipment requires application layer service communication. The detection equipment (except for a very small number of external mobile detection equipment) mainly works in the local area network with sufficient bandwidth.

[0032] The MQTT protocol is designed for communication between remote sensors and control devices on low-bandwidth, unreliable networks. It has the advantages of being lightweight and having a small network load. However, in the distribution network material detection platform, bandwidth resources are quite abundant, and material detection usually only transmits detected data with a small amount of data. Therefore, the advantages of MQTT are not obvious in distribution network material detection applications. In addition, the MQTT protocol has the following disadvantages:

[0033] 1. The MQTT protocol does not support file transfer and audio and video transmission. In the distribution network material detection, it is often necessary to transfer files, pictures and even videos.

[0034] 2. It does not support integration with third-party HTTP. At the application layer, WEB servers based on the traditional HTTP protocol still occupy the mainstream market. Therefore, it is particularly important for these servers to achieve interconnection with the MQTT protocol to reduce upgrade costs.

[0035] In comparison, the HTTP protocol has the following advantages:

[0036] 1. The HTTP protocol is simple, mature, easy to understand, with clear request and response formats, easy to implement and debug

[0037] 2. The HTTP protocol is flexible and supports various data formats, including text, images, video and audio.

[0038] In summary, the embodiment of the present invention uses the HTTP protocol as the communication protocol between the protocol converter and the material detection system main station.

[0039] Common network data transmission formats include: JSON, XML. The comparison of these two most commonly used data transmission formats is as follows:

[0040] ① XML: Extensible Markup Language. XML is a common language for data exchange. XML file format is widely used in the smart grid IEC61850 communication protocol. However, XML files are huge, transmission takes up bandwidth, and both the server and the client need to spend a lot of code to parse XML, resulting in complex and difficult to maintain code. Different browsers on the client parse XML in different ways, requiring repeated writing of a lot of code. The payload of XML is too low, and the encapsulation and parsing efficiency is low.

[0041] ②JSON: It is a lightweight data exchange format that is easy for machines to parse and generate. The data obtained in the collection phase is filtered according to the specific communication protocol, and the standard data is formatted. It uses a text format that is completely independent of the language. It can convert a set of data into a string, pass the string between networks or programs, and restore it to the data format supported by each programming language when needed.

[0042] At present, the JSON transmission format is convenient and easy to use, with clear layers and good scalability. It occupies the mainstream of applications, and there are codes and library files implemented in multiple languages ​​such as JAVA, Python, and C++ on the Internet, which is easy to program and use. The data content transmission in the material detection system communication message adopts the JSON transmission format.

[0043] The communication mode of the communication protocol of the present invention adopts a request response mode and a timeout retransmission mechanism.

[0044] (1) Request-response mode

[0045] like Figure 4 As shown in the figure, data transmission consists of the request from the applicant and the response from the feedback party. The specific implementation process includes: the sender sends a request command to the receiver. After receiving the request, the receiver responds to the sender's invitation (handshake completed). After receiving the response, the sender waits for the receiver's feedback. The receiver executes the request operation and sends the execution result to the sender. If the sender obtains the command result, the task ends. If the sender fails to collect the task information, it is processed as a task timeout.

[0046] (2) Timeout retransmission mechanism

[0047] ① Request response timeout: If a request command is issued and no reply is received within the time limit, it is a timeout; if the request is resent more than a certain number of times after the timeout, the communication ends.

[0048] ② Execution timeout: After the requester times out, if the instruction execution fails, the requester operation is terminated.

[0049] The request message structure and response message structure are as follows: Figure 5 and Figure 6As shown in the figure. The request methods of the request line include get, post, put, and delete. The required field names of the request header include Accept-Language (language), Content-Type (text type / image), etc. The blank line of the request header is used as a sign of the end of the request header.

[0050] Some of the main HTTP interface formats are shown in Table 1:

[0051] Table 1 Part of HTTP interface format

[0052]

[0053] The embodiment of the present invention designs a method for encrypting the message data using shaHmac256 of deviceID, random session number sessionID and random key sessionKey.

[0054] ① The host computer in the material inspection management system stores the number (device ID) of each protocol converter. This ID is unique and can be replaced by the MAC address of the Ethernet card of the protocol converter.

[0055] ②When the protocol converter communicates with the master station by handshake for the first time, if the sending master station checks the handshake message deviceID of the device in its own database, it will generate a random temporary sessionID and sessionKey for this session as the credential of this call, and return the sessionID and sessionkey to the detection instrument at the same time, which will be temporarily stored locally.

[0056] ③ The protocol converter first writes the JSON message of the data content of the message to be sent, then traverses the JSON structure, obtains the parameter names of all leaf nodes, and sorts them in reverse order of the first character to obtain a string set, which is assumed to be {para1s: XX, para2: XXX, para3: XX, …, paraN: XX}.

[0057] ④Add the sessionKey string of this session saved locally to the string set in ③:

[0058] {para1: XX, para2: XXX, para3: XX,…, paraN: XX, sessionKey: XXX}

[0059] ⑤Concatenate the strings in ④ together, then use the shaHmac256 algorithm to form a sign, and attach the value of the sign to the sign field in the message as a verification credential.

[0060] After receiving the data, the receiver first takes out the sessionID in the message, queries the sessionKey corresponding to the temporary sessionID stored locally, and then uses the sessionkey to perform the same encryption operation on the received request data. If it is found that the sign calculated locally is not equal to the sign in the data message, it is considered that the data has been tampered with during communication; otherwise, the data can be considered normal and pass data verification and identity authentication.

[0061] The following takes the communication between a master station and a transformer DC resistance measuring instrument (serial communication) as an example to illustrate the working process of the designed protocol converter and the communication protocol encoding method.

[0062] 1. Working process of protocol converter

[0063] ① After the protocol converter is turned on, it sends a handshake message to the master station according to the pre-set master station IP and port. The message contains the device ID of the protocol converter.

[0064] ② The master station obtains the deviceID of the converter from the handshake message information, and confirms that this handshake connection is legal according to the deviceID stored in the master station's own database. Then, the sessionkey and sessionID are assigned to this connection of the converter and stored in the master station's local connection information; and the sessionkey and sessionID are also sent to the converter;

[0065] ③After the converter receives the sessionkey and sessionID, it saves them locally in the converter.

[0066] ④ The master station will send a measurement data request message to the converter via HTTP using the GET method in the / api / station / getMeasureData format in Table 1.

[0067] ⑤ After receiving the message, the converter decodes it to obtain the command, then re-encapsulates the command according to the manufacturer's message format of the transformer DC resistance tester, and sends the command to the DC resistance tester through the serial port.

[0068] ⑥After receiving the command from the serial port, the DC resistance tester encapsulates the test data according to the manufacturer's own protocol and sends it to the converter through the serial port. After the converter parses it according to the manufacturer's protocol, it obtains the measured DC resistance data, and then encapsulates the data according to the distribution network material detection communication protocol (JSON encapsulation + security encapsulation + HTTP encapsulation) and sends it to the master station through the Ethernet port; the message format can be found in the following message format example;

[0069] ⑦ After receiving the data packet, the master station decodes it to obtain JSON data, and then performs security detection based on the sign field: query the sessionID in the message to correspond to the sessionKey stored in the master station, and then use the sessionKey to perform the same encryption operation on the received request data. If it is found that the calculated sign is not equal to the sign in the data message, it is considered that the data has been tampered with during communication; otherwise, the data can be considered normal and pass data verification and identity authentication. Obtain the measured high-voltage direct resistance data and low-voltage direct resistance data in the JSON data and put them into the distribution network material detection database.

[0070] 2. Taking the data message sent by the transformer direct resistance meter to the master station as an example, the protocol converter encapsulates it according to the communication protocol designed by the present invention, and its message format is as follows:

[0071] Request type: POST

[0072] Content-Type: application / json; charset=utf-8

[0073] The data is in JSON format:

[0074] {

[0075] "deviceID":"xxxx", / / Detection device code

[0076] "sessionID":xxxx, / / This session ID

[0077] "sign":"d0aacb409ffaaea1387c1640e3ccc8b4" / / digital signature

[0078] "measures":[

[0079] "dateTime":"yyyy-MM-dd HH:mm:ss", / / data time

[0080] "materialCode": "xxxx-xxx", / / Detected distribution transformer code

[0081] “manID”:”xxxx”, / / Inspector ID

[0082] "datas":[{

[0083] "parameter":"301", / / 301 is the high voltage direct resistance code

[0084] "value":3.569712 / / parameter value

[0085] }

[0086] {

[0087] "parameter":"302", / / 302 is the low voltage direct resistance code

[0088] "value":0.008368 / / Parameter value

[0089] } ] ]

[0092] }

[0093] Among them, the generation method of sign is as follows:

[0094] (1) Traverse the JSON structure in the message and obtain a set of all leaf nodes except sign in reverse alphabetical order:

[0095] {"value":3.569712,"value":0.008368,"sessionID":xxxx,"parameter":"301","parameter":"302","materialCode":"xxxx-xxx","manID":"xxxx","dateTime":"yyyy-MM-dd HH:mm:ss","deviceID":"xxxx"}

[0096] (2) Add sessionKey to the collection

[0097] {"value":3.569712,"value":0.008368,"sessionID":xxxx,"parameter":"301","parameter":"302","materialCode":"xxxx-xxx","manID":"xxxx","dateTime":"yyyy-MM-dd HH:mm:ss","deviceID":"xxxx","sessionKey":"xxxxx"};

[0098] (3) Concatenate the sets to get a string:

[0099] {"value":3.569712"value":0.008368"sessionID":xxxx"parameter":"301""parameter":"302""materialCode":"xxxx-xxx""manID":"xxxx""dateTime":"yyyy-MM-ddHH:mm:ss""deviceID":"xxxx""sessionKey":"xxxxx"}

[0100] (4) Use the shaHmac256 algorithm to encrypt the string in (3), generate a serial number, and fill it into the sign field in the message.

[0101] The present invention designs a protocol converter suitable for connecting a new type of power detection equipment to a distribution network material detection system. First, according to the distribution network material workflow and business characteristics, it is proposed to divide the distribution network material detection system into 4 layers according to business and function; then the working principle of the protocol converter is explained, and a communication protocol for the protocol converter to connect to the distribution network material detection system is designed. The protocol is based on the HTTP protocol, and the data encapsulation adopts the JSON format. A communication data encryption method based on deviceID, random session number, random key and shaHmac256 is designed to ensure communication security. The communication protocol in the designed protocol converter is based on the popular HTTP+JSON implementation. There are many open source cross-platform codes on the HTTP and JSON websites, which are easy to transplant, implement and expand.

[0102] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A communication protocol converter for a distribution network material detection system, characterized in that: It includes a protocol conversion module, a downlink physical interface connected to the protocol conversion module, and an uplink physical interface; The uplink physical interface is used to receive a first detection command issued by the material detection master station, where the first detection command is generated according to the distribution network material detection communication protocol; The protocol conversion module is used to decode the first detection command according to the distribution network material detection communication protocol, save it in the buffer, and then encapsulate the content of the decoded first detection command into a second detection command according to the private communication protocol of the detection instrument manufacturer, and send it to the detection instrument through the same downlink physical interface as the detection instrument according to the private communication protocol of the detection instrument manufacturer; The downlink physical interface is used to receive first detection data uploaded by the detection instrument according to the second detection command, where the first detection data is generated by the detection instrument after encapsulating the detection data according to a private communication protocol of the detection instrument manufacturer; The protocol conversion module is further used to decode the first detection data according to the private communication protocol of the detection instrument manufacturer, save it in the buffer, and then encapsulate the decoded detection data using the distribution network material detection communication protocol to generate second detection data, and then send it to the material detection main station through the uplink physical interface. After receiving the second detection data, the material detection main station decodes it according to the distribution network material detection communication protocol to obtain the detection data of the detection instrument; The distribution network material detection communication protocol is implemented based on the HTTP protocol, and uses the JSON format as the network data transmission format; The material detection master station saves the deviceID number of each communication protocol converter. When the communication protocol converter shakes hands with the material detection master station for the first time, if the material detection master station checks that the deviceID in the handshake message of the communication protocol converter is in its own database, it will generate a random session number sessionID and a random key sessionKey for this session as the credential of this call, and at the same time return the random session number sessionID and the random key sessionkey to the communication protocol converter, which will be temporarily saved locally. After the communication protocol converter writes the JSON message of the data content of the message to be sent, it traverses the JSON structure, obtains the parameter names of all leaf nodes, and sorts them in reverse order of the first character to obtain a string set, and also puts the sessionKey string of this session saved locally into the string set; Concatenate the strings together, then use the shaHmac256 algorithm to form a sign, and attach the value of the sign to the sign field in the message as a verification credential; After receiving the data, the material detection master station first takes out the sessionID in the message, queries the sessionKey corresponding to the temporary sessionID stored locally, and then uses the sessionkey to perform the same encryption operation on the received request data. If it is found that the sign calculated locally is not equal to the sign in the data message, it is considered that the data has been tampered with during communication. Otherwise, the data is considered normal, passes data verification and identity authentication, and then obtains the detection data in the JSON data and puts it into the distribution network material detection database.

2. The communication protocol converter for a distribution network material detection system according to claim 1, characterized in that: The uplink physical interface is an Ethernet interface, which is used to communicate with the material detection main station; the downlink physical interface includes an Ethernet interface, a serial port and a 485 interface, which are used to communicate with the detection instrument.

3. The communication protocol converter for a distribution network material detection system according to claim 1, characterized in that: The communication method of the distribution network material detection communication protocol adopts a request response mode and a timeout retransmission mechanism.

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