The power dispatch automation system is a fundamental infrastructure for power grid operation and management. Since its implementation in May 2001, our county's power dispatch automation system has played a crucial role in ensuring the safe and economical operation of the power grid and improving power supply reliability, yielding significant economic and social benefits. However, due to our emphasis on perfecting the functions of the main station and substations during the construction of the dispatch automation system, while neglecting the construction of communication channels, communication failures have occurred frequently since its operation, severely restricting the full functionality of the dispatch automation system. I. Existing Problems In the construction of the dispatch automation system's communication channels, to save on construction costs and shorten the construction period, most substations leased communication channels from the telecommunications bureau (including dedicated lines and dial-up lines). Through nearly 10 months of operational practice, this type of channel has many drawbacks. The power grid in the eastern mountainous area of ​​our county has four substations and two hydropower stations, making it one of our company's important load areas. The safe and economical dispatch of the power grid in this area is a key task of our county's power dispatch automation system. Due to the presence of small hydropower stations, the operation mode is also relatively complex. Data from two hydroelectric power stations is transmitted to the Zhicun substation via power line carrier wave. Then, port multiplexing technology is used to transmit the data from these three substations to the main dispatch station via telephone lines from the telecommunications bureau. The other three substations (Bainiuchang substation, Smelting Plant substation, and Beijiao substation) are also all connected to the main dispatch station via telephone lines. All four leased telephone channels are dial-up lines, belonging to the rural lines of the telecommunications bureau, which are unreliable and frequently experience communication interruptions. The Bainiuchang substation, located in a remote mountainous area, experiences the most severe channel obstruction problems, sometimes only able to communicate normally for a few hours a month, seriously hindering the normal operation of the dispatch automation system. The main reasons for the frequent telecommunication channel obstructions are: 1. The data transmission rate supported by a communication channel is directly proportional to its bandwidth; the wider the bandwidth, the higher the data transmission rate. The bandwidth provided by the public telephone system basically covers the frequency range of voice, which is sufficient for voice communication, but it limits data communication between the main station and substations in a wider frequency range. 2. To reduce investment in line construction, telecommunications departments often use low-quality access equipment at the user end. External environmental factors (such as rain and fog) can easily alter the distributed parameters of the lines, increasing noise and leading to high data error rates, thus affecting the transmission of dispatch data. 3. Telecommunication channels are managed by the telecommunications department, and users cannot restore them themselves when problems occur. Furthermore, the telecommunications department generally has low service efficiency and slow response speed, resulting in excessively long channel troubleshooting times, which cannot meet the real-time communication requirements of the dispatch system. II. Solutions Building our own communication channels to ensure smooth communication between the dispatch master station and substations has become an urgent task for the practical application of our county's dispatch automation system. Using a large number of self-supporting optical cables (ADSS) and spread spectrum radios to build a communication network is beyond the company's capacity; moreover, our county is located on a plateau with extremely undulating terrain, making implementation difficult. The most realistic option is power line carrier. Although power line carrier can only transmit one voice and one data channel, and the data transmission rate is not high (not exceeding 1200 bits/s), the communication capacity of the county-level dispatch automation system already meets the needs. If higher requirements are needed, digital carrier units can also be used to transmit multiple voice and data channels. Modern power line carrier (PLC) systems have largely replaced discrete components with integrated circuits, significantly improving reliability compared to older products. Therefore, we believe that leveraging our own conditions and the resource advantages of the power system to construct a dispatch automation communication channel primarily based on PLC is feasible. Regarding the North Suburb substation (approximately 4 kilometers) closest to the dispatch master station, we propose two solutions for the shortest possible access: 1. PLC – Fiber Optic Solution: After the carrier signals from each substation converge at the North Suburb substation, a computer is set up as the communication management unit, and a 4-kilometer fiber optic cable is laid to transmit the data from each substation to the dispatch master station via fiber optic cable. 2. PLC – Spread Spectrum Solution: A spread spectrum channel is established between the North Suburb substation and the dispatch master station. The data from each substation is multiplexed into a single data stream and then transmitted point-to-point via a spread spectrum radio. Both solutions meet the communication requirements of the dispatch automation system in terms of both reliability and data transmission rate. Solution 1 is superior because the required fiber optic cable length is shorter, and multiple 10 kV lines from the North Suburb substation to the dispatch master station can serve as fiber optic channels. III. Conclusion The communication channel of a dispatch automation system is a crucial component of the system, and its completeness directly impacts the system's normal operation. In channel construction, we must neither unilaterally emphasize cost-saving nor waste resources in pursuit of perfection. Instead, we must base our approach on the system's basic requirements, leverage existing conditions, conduct thorough technical and economic comparisons, and select the optimal solution to ensure the stable operation of the dispatch automation system.