Design Of Embedded Software Platform Of Power Automation Devices

In recent years, with the construction of smart grid, the development of intelligent substation and the emerge of AC and DC systems interconnection, power system put forward new requirements for relay protection, measurement and control device and safety device. The application of intelligent primary equipment, electronic transformer, digitized secondary circuit and IEC-61850 standard brings new change to the architecture and the implementation of power automation devices. Because of these new demands and changes, the requirements that the entire power grid to power automation devices are also getting higher and higher, and the urgency to develop the embedded software platform adopting new technology to adapt to the new change is more and more strong, therefore, this paper proposes a new design of power automation devices embedded software platform. It has certain practical value to the development of power automation device and the renovation of software.Based on clearly structured, versatile, scalable and reliable embedded real-time operating system, power automation devices embedded software platform is developed by summarizing and extracting the common demand of power automation devices. The embedded software platform designed in this paper adopts multi-layer architecture. It consists of three layers, the lower layer is device drivers and operating system adaptation layer, the medium layer is software platform layer, and the high layer is application layer. The functions of software platform layer is classified according to software modules. Each module provides API interfaces for the application layer. Developers can build varieties of different applications by calling different functions and software modules. The design of software platform layer could decouple the lower layer and the application layer to enhance scalability and adaptability. The programs of device drivers and operating system adaptation layer could be replaced according to the specific hardware platform, and the kinds of real-time operating system could be selected arbitrarily by developers, therefore the portability of the embedded software platform has been greatly improved. Device drivers, operating system and software platform layer as the foundation and support of applications provide necessary API interfaces for application development. For the software platform layer which has abundant function modules, its main function modules are analog management, binary input management, communication, time management, data calculation, setting management, configuration management, record management, self-checking management, binary output management and so on. Each module can offer the interfaces to access its function. According to these API interfaces, this paper use C language to design and program some functions, including the function’s call entrance, variable name and type’s registration, structure and logic. They are the minimal set of function implementation and the operating foundation of embedded software platform.Finally, according to the three layers architecture and API interfaces between the layers of the embedded software platform, this paper expounds the specific application development framework. Applications are divided into tasks and assigned to different priority respectively. The tasks follow the preemptive task scheduling mechanism, and the software platform carries out application functions in accordance with task running processes. By development example of the over-current protection logic of relay protection device, the practical effect of power automation devices embedded software platform designed by this paper is verified.