Re-Configuration of IED for Decreasing Cyber Security Threat at SCADA based Substation

Abstract

SCADA systems have proven well to increase the efficiency and reliability of power grid
system. However recent attack on SCADA system at some utility companies, put SCADA
security to be a critical issue on power industry today. The use of TCP/IP as a carrier
protocol and the trend to interconnect SCADA systems with enterprise networks, create
serious security threats. This paper proposes re-configuration of IED (Intelligent
Electronic Device) or microprocessor-based controllers of power system equipment, such
as circuit breakers and transformers, at SCADA system to decrease cyber security threat
at Substation level. The re-configuration is conducted by three methods; by not
connecting the communication lines to the protection relays, change the bay control unit
function to the bay monitor unit, and then optimizes the mimic bay control. It will limit the
accessibility of Substation from the local HMI system, LAN remote station network,
communication network between Master Station and Remote Station, communication
network inside Master Station and office, and backdoor network to the vendors. Indeed
this re-configuration still support the SCADA main functions to monitor all main
parameters of power grid system, only disable the automatic mode of PMT operation at
Substation. Using a risk matrix this study found that the reconfiguration can reduce
significantly the cyber attack risk value. The change of standard of operation is proposed
to ensure that reconfiguration will be worked well