On December 17th , 2005, the Department of Science and Technology of Jiangsu Province organized experts to carry out a full acceptance check for the project “PA300-L Digital Line Protection Device” undertaken by Nanjing Intelligent Apparatus Co., Ltd.. Experts listened to the project principals’ work summary and technical report seriously, examined relevant documents carefully, and inspected the production field in high spirits. They gave high opinions to INT’s technical development force, and the fulfillment of the acceptance check.
PA300-L Digital Line Protection Device is a complete line high-speed protection device employing distance protection, zero sequence protection and 3-phase 1-time reclose, with the voltage switch box and the 3-phase control box integrated. It is applied as the primary and back-up protection of 110kY, 66kY or 35kY transmission and distribution lines. The device adopts the modular design of 32-bit SCM+DSP, whose data sampling systems both have independent electronic circuits. Only SCM works to start the positive voltage of the exit relay, really ensuring no mis-operation due to damage to any parts. DSP deals with protective operation and logic discrimination, while SCM with the start-up, communication interface, incident and fault record.
With a high sampling rate (24 points/week), the device ensures the completion of all protective operation and logic discrimination in each sampling interval, realizing real-time parallel computation of all protective relays. The main relays adopt Holocycle Fourier Algorithm, with high reliability and security. Incident record collation and protective logic computation can be done at the same point to avoid any misplacement or loss of report due to the asynchronous start of CPU plug-in under a complicated fault.
The project’s research and development was highly valued and strongly supported by the Department of Science & Technology of Jiangsu. INT invested a lot in the project with the R&D expenses of 3 million Yuan RMB. The project lasted two years and finally made the riffle. An invention patent had been applied for the project. The project’s all technical specifications reached and even surpassed the expected goals. Experts also acknowledged that the project reached the international leading level.
We will apply the new-type 110KV and above power system protection device to the electric network systems more to popularize its technological advantages and reliability.