Intelligent Substation Fiber Differential Protection Device Design And Implementation

In the smart substation,line both sides of the line data synchronization problem is fiber differential protection device design and implementation of the main difficulties.Known as line ends sampling time differences, resulting in a line across the data is not synchronized.That both sides of the original sample data or transfer current vector is not the same amount of time, according to Kirchhoff s current law to calculate the differential current on both sides.You need to synchronize the data on both sides of the first line to the same time. The traditional synchronization method has the following methods:sampling time adjustment method, the data adjustment method, the clock correction method, the reference phasor and GPS synchronization method.As intelligent substation construction has just started, the line ends for data collection, is now in a variety of ways. Both sides are the traditional way, but also full of digital acquisition mode, there is a combination of both, which gives itself complex data synchronization issues become more complex.Articles by traditional Comparison of several methods discussed whether these methods are applicable to international standard IEC61850-9-1or IEC61850-9-2, was proposed based on Langella day pong interpolation synchronization method to solve both sides of the data synchronization problems.Ping Pong interpolation based Langella day synchronization method has been applied to the actual light differential protection device, the performance of its synchronization accuracy is relatively high, the synchronization angle is greater than the maximum error of1.0°.Since the light transformer technology is not mature, intelligent light transformer substation in the practical application of a lot of problems, there is not a large-scale popularization and application. Intelligence gathering of current and voltage substation now generally or the use of conventional electromagnetic transformer, just use intelligent terminal device, the data will be collected in situ of the function.Normal mode optical fiber differential protection device hardware can be divided into CPU control module, AC acquisition module, open into the acquisition module, digital output modules, LCD modules, fiber optic communications and power modules in seven parts.Intelligent substation fiber differential protection device is POWERPC+FPGA chip as the core logic, using the standard C language modular programming. These modules to protect the main program loop program modules, each chip initialization module, sampling data processing module, line differential protection module, phase and ground distance module, four zero-sequence directional current protection module, reclose module, after acceleration module, overload module, two two time TV after the break overcurrent protection modules, modules and other quick succession protection module.These hardware and software modules by the end of the smart substation fiber differential protection device. RTDS Simulation Laboratory at the unit for a full-function test, simulate a variety of situations within the region and outside the failure to carry out a ten thousand times the dynamic modulus test, the device did not happen tripping and malfunction, and the action precision to the national standard. Test results show that the design is feasible.