Communication Control Apparatus for High Precision Time Synchronization
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Solution Overview
Problem
Existing time synchronization protocols in distributed control systems face challenges in achieving high precision synchronization due to fluctuations in forward and backward delays caused by queuing in network relay apparatuses, making it difficult to configure networks with standard connection terminals and relay apparatuses.
Innovation Solution
A communication control apparatus and protection relay system that determine the occurrence of packet collisions by measuring reception intervals and setting threshold values, allowing for precise time synchronization by adjusting communication protocols and re-executing synchronization protocols as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time synchronization protocol is executed in a network with relay apparatus, then time synchronization can be achieved, but synchronization accuracy deteriorates due to queuing delays and forward-backward delay fluctuations
Solution Approach 1:
The invention measures the forward delay and backward delay separately before calculating the time difference, allowing compensation for queuing delays that occur during the synchronization process. By preliminarily measuring these delays and using them to correct the time synchronization calculation, the system compensates for the instability introduced by relay apparatus queuing.
2Ease of manufacture
If standard network relay apparatus are used, then network configuration becomes easier, but time synchronization precision decreases due to packet queuing
Solution Approach 1:
The invention introduces a feedback mechanism where the measured forward delay and backward delay are used to correct the time synchronization calculation. The system continuously monitors these delays and adjusts the synchronization accordingly, allowing standard relay apparatus to be used while maintaining synchronization precision through mathematical compensation.
3Productivity
If time synchronization packets are transmitted through shared network, then network resource utilization improves, but forward and backward delays become unequal due to packet queuing
Solution Approach 1:
The invention changes the approach from assuming equal forward and backward delays to separately measuring and utilizing the actual forward delay and backward delay values. By changing the parameter from a theoretical equal delay to actual measured delays, the system accommodates the unequal delays caused by shared network queuing while maintaining synchronization accuracy.
Data Source
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AI summary
The objective of the invention is to enable a time synchronization of high precision, while using ordinary apparatuses to configure a network. For this purpose, a communication control apparatus comprises: a time synchronization processing unit 130 that executes a predetermined time synchronization process for a plurality of communication apparatuses in a network; a reception interval measurement unit 134 that measures reception intervals of response packets from the plurality of communication apparatuses; a reception interval threshold value determination unit 136 that establishes a reception interval threshold value by use of network configuration information stored in a network configuration information storage unit 151; and a queuing occurrence determination unit 135 that compares a measurement result of the reception interval measurement unit 134 with the reception interval threshold value established by the reception interval threshold value determination unit 136, thereby determining whether any collision of the response packets from any ones of the plurality of communication apparatuses has occurred. The time synchronization processing unit 130 determines, on the basis of a detection result of the queuing occurrence determination unit 135, whether to continue the predetermined time synchronization process.