The Research Of Protection Algorithm And The Design Of Software Apply To Distributed Power Monitoring And Protection Devices

Distributed Generation (DG) is not a new power generation technology, before theelectricity as energy to drive the load replace the water, steam, coal-fired energy, the vastmajority of electricity is distributed in the near the equipment which needed energy. As thepower system which with the concentration of power production, long-distance of powertransmission and large grid interconnection of power distribution mode to be the90percentof the electricity supply in the world. The problems are also growing. With large distributedpower grid parallel operation to become the development direction of the electric powerindustry in21st century. However, distributed power protection is different from traditionalrelay protection. This paper focuses on the main impact of power protection after thedistributed power grid to design a microprocessor-based back-up protection device.Paper first analyzes the grid of distributed power to influence of the traditional gridrelay protection, establish the distributed power grid model, and through analysis the gridmodel and the relevant knowledge of relay, design the distributed power gird protectionfunction and setting the value of protection. Based ARM embedded to design amicroprocessor-based distributed power monitoring and protection devices.Then a brief introduction about the protection of distributed power protectionhardware design, based on the minimum system of LPC2468to design the AC samplingcircuit, switch input and output circuits, frequency measurement circuit.Paper focuses on various methods of calculating the amount of electrical power, thepurpose of protect the algorithm is to calculate the useful signal from the discrete samplevalues, provide accurate and real-time data to the logical decision for the protection. Thereare many protection algorithms, the proposed algorithm for distributed power protectiondevices are: the phase detection algorithm based on the synchronizing grid, the componentsstarting algorithm based on mutation, the calculation method of the current and voltagesequence component, the detection algorithms of harmonic components and the detectionalgorithm of basic electrical quantities. All the algorithms are not based the same signalmodel that can be divided into sinusoidal signal model, random periodic signal model andsignal model. In terms of the time window, accuracy, speed and computation to analyzeadvantages and disadvantages of each algorithm.Finally, embedded operating system uC/OS-â…¡ successfully transplanted to the LPC2468hardware platform, then based on which to establish a multi-task design, eachfunctional unit is assigned to a task, time sampling interrupt task, the protection algorithmtask and the fault processing task are the most important part, and all the tasks coordinate tofinish a series of works that grid connection, inspection and monitoring, fault cleaning.Distributed power monitoring and protection device is a new subject area, its mainfunction lies on signal detected of the both sides and to design the back-up protection forauxiliary the internal main protection of distributed power and grid protection equipment,with the a large-scale distributed power grid, the space of its use will unlimited breadth.