Design And Implementation Of Vocie Over IP System In Underground Substations

With the popularity of VoIP and related technologies and protocol, VoIP is not only widely used in the SME voice communications, but also more and more applications in the industry. As the environment of industrial applications rather special, it demands the customization of VoIP technology and system development, deployment. In this thesis, the author analyzed how to apply the VoIP technology and design, implement and deploy VoIP systems for underground substations. The main innovations can be summarized as follows:1. Through studying for informatization and development of transformer substation, demonstrated the importance and crital that deploy, design and implement VoIP in transformer substation, espeically for uderground substation.2. Based on systemic analysis of the principles, system architecture and protocls of VoIP, analyzed and compared the signaling protocols, to choose the SIP protocl in project.3. Analyzed the applicaiton environment of VoIP, according to the situation of substations, customized the functionalities of VoIP. And presented the design of hardward and softward.4. Implemented hardware platform of VoIP, using PowrPC processor as CPU, which applied widely in industry, and DSP with hard codec for voice to ensure the quality of VoIP voice communications and the stability of the platform, while SLIC chip was selected to control and manage the external phone, which could make normal phone access to the VoIP system easiliy. These designs could meet the needs of voice call in the substation.5. Developed VoIP software. The modules with different functions worked well toghter by the definition of events and the interaction between the child processes, which achieved the function of voice communication. The software architecture is easy to extend and has very good versatility.6. According to the needs of the substations, realized the VoIP broadcast in substation, which has great significance for the work of risk control and preventation in substation. The way that one child process was created to serve broadcast function, seeting on DSP/SLIC/CODEC, Paging funciton of Asterisk, achieved the function of VoIP broadcast. The design of hardware and software architecture can be easily ported to different environments.