Implementation of HVDC-Emergency Power Control at HVDC Raigarh by Integrating two different Geographical locations through IEC 61850 Platform over SDH Network

In addition to bulk power transmission from Western to southern region in forward direction, Raigarh-Pugalur 800KV HVDC Transmission link (RP-800) [2] is also utilized for high renewable energy export from southern to western region in reverse direction. This link provides high level controls like Emergency Power control (EPC), Frequency Controls, Power Oscillation Damping, to stabilize the grid during contingency. Emergency Power Control application operates on availability status of Load evacuating feeders, Frequency control and Power oscillation damping control work on variation in frequencies. To avoid the interaction of these controllers among each other, there is priority interlocking and amongst all EPC is given the highest priority. Further EPC application is dedicatedly designed for reverse Power direction only where green energy generated during Monsoon and winter in southern region is being exported to northern region via RP-800. EPC requires connected status of all available load carrying feeders in reverse power scenario and extensive grid study. The study was performed during project dynamic performance study on PSCAD model to determine the next safe Power level which can be injected into AC grid so that system will run without any major dynamics. Emergency Power control feature modulates the POWER ORDER of respective HVDC Bipoles in Active Master Control system and Ramps down the Power Export by RP-800 HVDC link during contingency/sudden load rejection, so that other available elements of Power system should not overload and minimize the disturbances/Power swing. During the reverse power scenarios, the Power exported by southern region is evacuated by HVDC CHAMPA KURUKSHETRA BIPOLE 1 (CK1) links from western to the northern region along with 4 Nos. of 765/400KV ICTs at Raigarh Pooling station. Hence status of CK_1 and Champa to Raigarh 400KV AC tie lines via LARA STPP were required for implementation of EPC at RP800. Major challenge in implementation of EPC was to integrate these signals from CHAMPA over distance of 100KM with fast and reliable signal interface... Further options for integrating telecontrol signals via IEC 61850- Interstation GOOSE was explored. Though IEC61850 GOOSE is widely accepted technology for horizonal communication between the substation bays for fast and reliable control and protection signals in the modern electrical power substations, its applicability , speed, reliability & effectiveness over for Telecontrol system between the different substations, was still concern due to different network architecture and cyber security risks , which makes transmission of GOOSE through telecontrol over different logical and physical networks more challenging. This paper presents the utilization of IEC61850 GOOSE signals for TELECONTROL of EPC application at 800KV, 6000MW HVDC RAIGARH. In the scheme presented hereunder, IEC61850 GOOSE signals were transmitted from CHAMPA to RAIGARH over almost 100 KM FIBER OPTIC TELECOM network via SDH channel across the two different substation networks. To mitigate cyber security attackers’ risk, Layer 2 MAC addresses and VLAN traffic tagging encryptions at both end is envisaged via transparent Firewall policies. Further, similar schemes may be adopted in the future for telecontrol/tele protection applications with efficient network topologies to optimize electrical substation design.