Full Description

The City of Wilsonville, Oregon, initiated a project to completely redesign and replace both of its water and wastewater supervisory control and data acquisition (SCADA) systems. The existing leased telephone line communication systems were replaced withindependent, secure licensed frequency wireless radio networks. The existing legacyhardware for the central Master Telemetry Units (MTU) and Remote Telemetry Units(RTU) were replaced with Programmable Logic Controllers (PLC).This paper describes the security design considerations and system integration methodsfor the project. Key elements include the hardware and software security features of theselected communication and control components. The communication system radiomodems provide multiple layers of security from four main threats to wireless datacommunication. The engineering and configuration software for the PLC componentsadds an additional security layer through unique node addressing and password protectedlogin requirements. Monitoring and control access is implemented at the local levelthrough Operator Interface System security constraints and login procedures. Remoteintrusion alarming and monitoring is implemented via physical security hardware.Data from the City's utility systems is collected by three data historian applications. Thesystem design includes secure access to each of the four utility control system networksfrom five separate locations over the City's business LAN network, and from authorizedexternal nodes. These connections are used for data access, management and reporting,Operator Interface control, and PLC engineering work station functions for the MTU andRTU sites. Discussion includes implementation of the control system network access andsecurity policy, procedures and practices. Includes 7 references, table, figures.

Product Details

Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 35File Size: 1 file , 1.6 MB