To date, the master station systems of various power dispatching energy management systems (EMS) are connected to hundreds of remote terminal units (RTUs) or monitoring systems at 220 kV substations, 500 kV substations, and centrally dispatched power plants via direct data acquisition. Simultaneously, an equal number of provincial gateway energy acquisition units (ERTUs) are connected to the provincial dispatching EMS master station system via dedicated lines, shared lines, or telephone dial-up. This master station system has become a crucial support platform for ensuring the safe, stable, economical, and high-quality operation of the power grid, and its functions and roles have become indispensable tools for power grid dispatching and operation management. The proper functioning and use of these systems depend on the accurate, complete, rapid, and uninterrupted transmission of remote data from the substations and power plants. Without this basic remote data, the EMS master station system would be powerless. Currently, the telemetry equipment communicating with the power dispatching EMS master station system includes both computer monitoring systems and traditional RTUs and ERTUs; moreover, the access protocols are quite complex, including CDT, National Standard 101, East China Standard 101, SC1801, 103, 104, and DNP3.0. Once a fault alarm for a substation appears in the master station's RTU or ERTU operation summary, operators often have to use a comprehensive approach, checking each link from the substation's telemetry equipment and telemetry channels to the master station system to find the cause of the fault. Then, corresponding measures are taken to troubleshoot the fault, affecting equipment uptime. Even when the substation's telemetry equipment and the master station system are communicating normally, individual telemetry measurements (including electrical energy) may fluctuate or become inaccurate, or remote signaling may jitter. These disturbances in telemetry information affect dispatching operations and, more importantly, the security of the EMS master station system. The Guangdong Provincial Power Dispatch EMS master station system once experienced a large number of remote signaling fluctuations at a substation, causing numerous remote signaling alarms in the master station system. This junk information consumed system disk space, leading to a server crash and seriously threatening the security of the EMS master station system. For such faults, it is often difficult to quickly determine whether the problem lies with the master station or the substation's remote control equipment. Even if it is determined to be a problem with the substation's remote control equipment, strong evidence is often lacking. Therefore, automation operators urgently need an advanced remote control communication protocol testing and analysis system that can quickly and accurately diagnose faults, minimize downtime, ensure the safety of the EMS system, and better serve dispatch operations. To this end, Zhuhai Yitong Power Technology Co., Ltd., drawing on years of engineering experience and a deep understanding of power dispatching systems, has successfully developed the ET-2000 power protocol analyzer. Currently, the ET-2000 has successfully passed performance testing and is in official use. Here, we provide a brief analysis of the system's interface and performance characteristics. **1. Interface and Performance Characteristics** 1.1 Interface This system is written in Visual C++, providing a user-friendly interface. It features flexible operation, convenient setup, reliable operation, and comprehensive functionality. The interface consists of six main parts: 1.1.1 Toolbar: Sets login and logout passwords to prevent accidental operation or unauthorized exit from the listening state. Configures station name, communication interface type, protocol type, and related parameters. Buttons for starting or terminating the main process (SCAN), saving and opening channel data, clearing the data area, and event boxes, etc. 1.1.2 Frame Flow Summary List: Displays frame occurrence time, uplink/downlink direction, and frame category using color coding. 1.1.3 Raw Data Display: Displays specific message data content, occurrence time, transmission direction, and message type using color coding. 1.1.4 Frame Data, Remote Signaling, Telemetry, Remote Control, and Event Boxes: Displays specific information for each of the above types. A) Frame Data: Displays the data content of a frame. Clicking on each byte provides a detailed explanation. B) Telemetry: Displays the information body address, telemetry point number, and telemetry change timestamp. Sequential change and avalanche tests can be performed when simulating a substation. C) Telemetry: Displays the current measurement, telemetry point number, and telemetry timestamp. In a simulated substation, telemetry settings include: dead zone value, coefficient, alarm upper limit, alarm lower limit, and over-limit alarm. Simulated telemetry changes include random and sinusoidal. D) Remote Control: Displays remote control information sent by the master station, including type and time. E) Event: Displays the information body address, event content timestamp, and category of the event. Clicking on an event automatically finds the corresponding message, facilitating user analysis. 1.1.5 Frame Details Tree: Provides detailed analysis of each frame of data, including frame category, transmission direction, link address, information body address, etc., with detailed Chinese explanations for each byte of the frame. 1.1.6 The command window simulates the master station's command sending function, and each simulated command can be edited in the form of command parameters. Clicking send and pause allows users to edit the test command flow table and modify the execution interval (default 's'). Clicking execute will send the organized messages one by one at the execution interval. 1.2 Main Performance Characteristics 1.2.1 Simulated EMS Master Station Function The simulated EMS master station function includes master control and listening functions. 1.2.1.1 Master Control Function When in master control mode, the system communicates with the plant's remote control equipment via a modem through the PC serial port. At this time, the system simulates the EMS master station function, which includes: a) Issuing commands according to various communication protocols and receiving real-time data. This function can achieve communication with the plant's remote control equipment by issuing command sequences of various communication protocols consistent with the master station in automatic execution mode, and can also issue commands in single-step or batch execution mode according to the operator's requirements, while simultaneously receiving remote control data from the plant's remote control equipment. These data can be displayed in the message area or saved and converted into data tables for easy archiving and future analysis. b) Analysis of sent and received communication protocols. This function performs real-time analysis of the message content of various sent and received communication protocols, including message type identifier, transmission reason, information body address, and information body content. Even erroneous messages can be analyzed and the error location can be identified. c) Full or categorized recording of telemetry information. This function can fully record the commands and responses sent and received by various telemetry communication protocols, and can also categorize and record remote signaling changes, telemetry jumps, and SOE events according to operator settings, forming text files. Each text file name includes the plant name and recording time for easy user retrieval. d) Channel communication quality testing. This function is only applied to four-line dedicated channels and has two testing modes: closed-loop and open-loop. Closed-loop testing involves bypassing the remote control equipment at the plant and connecting the four dedicated lines into a loop. A series of test messages are then sent from the master station; the length of these messages can be set by the operators. Simultaneously, the number of erroneous packets and the current bit error rate (BER) of the channel are calculated by comparing the received and transmitted data packets. Open-loop testing, on the other hand, tests the communication quality of the channel while maintaining normal communication between the system and the plant. Similarly, the number of erroneous packets and the current BER are calculated. Regardless of whether it's closed-loop or open-loop mode, after the channel test is completed, clicking "Save" will save the test record to a file. The file records the start and end times, transmitted data packets, received data packets, transmission length, erroneous data packets, BER, and the detection method (open-loop or closed-loop). 1.2.1.2 Listening Function: When the listening function is enabled, simply connecting a pair of receiving or transmitting lines of the system to the receiving or transmitting end of the remote control channel allows online listening to the master station's transmitted commands or the plant's response data. Under surveillance conditions, the system functions largely the same as the main control system, except that it cannot issue commands; therefore, this will not be repeated here. 1.2.2 Functions of the simulated plant remote control equipment a) Simulates the RTU of a traditional four-wire remote control channel to send messages of various protocols. Simultaneously, it can modify the telemetry and tele-signaling values ​​sent by the RTU, and can monitor and save communication messages with the master station in real time. b) By modifying the configuration, the system can simulate a network RTU. If the local machine is a tcp_client, the IP address of the peer needs to be entered. If the local machine is a tcp_server, no IP address needs to be entered, indicating that it can accept client connections from any IP address. Both tcp_client and tcp_server require the network port number to be entered. [b]2. Application Status[/b] Although the ET-2000 has not been used for very long, due to its relatively complete functions, flexible use, and convenient operation, it can well meet the debugging requirements of operators for the master station system, plant system, channels, protocols, etc., in the power grid dispatch automation system. Therefore, it has achieved good application in infrastructure projects and operation and maintenance. 2.1 In terms of infrastructure projects, any newly built or expanded power plant remote control equipment or power energy acquisition devices must undergo multiple commissioning and information verification processes before formal commissioning. With the rapid development of the power industry, a large number of power infrastructure projects are connected to the grid and put into operation every year. These projects include not only newly built power plants and substations, but also numerous expansion projects for lines, main transformers, and generator units. Before using this system, we directly connected the automation equipment of newly built or expanded power plants to the main station system and commissioned it through a front-end server (whose operating system was UNIX). However, using the front-end server for commissioning has several problems: since the main station only has two front-end servers, only two power plant devices can be commissioned simultaneously. However, in actual operation, we often encounter situations where multiple plant equipment need to be debugged simultaneously, resulting in "debugging conflicts." During the debugging process, modifying or downloading parameters is cumbersome and carries certain risks. Communication messages between the master station and the plant equipment cannot be recorded and saved. During the information verification process, since all remote signaling of the plant must undergo linkage tests of opening and closing, and telemetry must be loaded with various types of analog quantities, the master station will inevitably generate a large number of remote signaling alarms and SOEs, and may even cause accident replays, threatening the normal operation of the master station. When using this testing system for debugging and information verification, there are no "debugging conflicts." Any PC with the software installed can perform debugging. Furthermore, the ET-2000 human-machine interface is user-friendly, making parameter modification and downloading very convenient and risk-free. Additionally, the system can easily record and save communication messages between the master station and the plant equipment into text files, facilitating analysis by relevant personnel to identify errors and promptly request the equipment manufacturer's debugging personnel to modify the program, thus shortening debugging time. During information verification, it can complete various information transmission tests according to user requirements without posing any threat to the operating master station. Only after completing the debugging work on these plant stations using this testing system are they connected to the dispatch master station and put into actual operation. Therefore, it is evident that using this testing system for infrastructure project debugging can improve work efficiency, shorten debugging time, and reduce interference and impact on the normal operation of the master station. 2.2 In terms of operation and maintenance, this testing system plays two main roles: a) When the main station system's plant equipment operation summary shows a fault in a plant's operation, using the main control function of this testing system helps to quickly determine whether the fault lies with the plant equipment, the remote control channel, or the EMS main station. b) When abnormal remote control data received by the main station occurs, such as telemetry jumps or erroneous and frequent jittering of remote signaling, the monitoring function of this testing system can be used to monitor the communication between the main station and the plant equipment for a period of time, and record all relevant changes in telemetry (the jump range is determined by the operator according to the actual situation) and remote signaling changes. Operators can query and analyze these records to determine the root cause of the fault and provide a basis for correct troubleshooting.