Research On Asymmetric Characteristic Of Channel Delay Of Line Current Differential Protection Based On PTN

With the acceleration of the development of smart grid,power communication network services face the evolution from traditional SDH technology to IP packet technology.The increasing number of services forces time division multiplexing to statistical multiplexing as the base of power communication network,which provides a broad application prospect for the development of PTN technology.The TDM service of line current differential protection channel not only requires that the communication delay is small enough,but also requires that the transmission and receiving delay of the channel have good symmetry.This is a challenge for PTN technology to carry power communication services,so it is necessary to have sufficient theory and simulation data to support it.Based on the study of the delay characteristics of TDM services on PTN network,the article analyzes the composition of end to end one-way transmission delay and establishes a mathematical model of delay.The article delves into the question of whether all delay components are random,and finds out the influencing factors of delay asymmetry.The algorithm of de-jitter buffer function is programmed by numerical simulation method.The parameters affecting the asymmetric delay are optimized according to the service performance index,and the parameters of the communication index are set up.The article proposes an asymmetric delay control method and verifies its feasibility through simulation.In order to verify the feasibility of PTN replacing SDH as a new relay protection channel implementation in line current differential protection service,an example of relay protection in practical application is applied to realize the simulation.The analysis of the delay mathematical model shows that the end to end one-way transmission delay can be divided into three parts or eight delay components for analysis.The queue delay in intermediate nodes and the packet buffer delay are the factors that cause the asymmetric delay.The numerical simulation gives an optimization scheme for the parameters of the asymmetric delay,which makes the performance of TDM basically conforms to the communication standard.Through the asymmetric delay control method,the reasonable control of the number of packets in de-jitter buffer can achieve symmetrical delay of the packet transmission.The simulation results of transmission delay under specific circumstances are obtained by example simulation,which verifies the feasibility of PTN replacing SDH as a new relay protection channel implementation.The research results of the article provide theoretical support for TDM services on PTN network,and have certain technical guiding significance and engineering reference value in the study of the delay of line current differential protection channel.