THE APPLICATION OF THE APPLICATION OF GPRS FOR SCADA GPRS FOR - PowerPoint PPT Presentation

THE APPLICATION OF THE APPLICATION OF GPRS FOR SCADA GPRS FOR SCADA COMMUNICATIONS COMMUNICATIONS Dieter Gütschow Telecommunications specialist Industry Association Resource Centre African Utility Week, 8­10 May 2006

Overview • Introduction • GPRS technology • Application of GPRS for SCADA • Proposed GPRS architecture • Conclusion

Introduction • Eskom’s private mobile radio network for SCADA ☺ Point­to­multipoint ☺ Good geographical coverage ☺ High reliability ☺ Low terminal costs � Slow data rates � Limited capacity � High total cost of ownership

GPRS technology GPRS ­ General Packet Radio Service • Supplements other data transfer methods • 2.5G technology 2G 2.5G 3G GPRS GSM WCDMA circuit switched 115 kbps 9.6 kbps 384 – 2000 kbps GSM HSCSD EDGE 43.2 kbps 384 kbps

GPRS technology • Data speed – Between 9kbps – 57.6kbps – Ave: 20­30kbps • Immediacy – No dial­up necessary (15s) – New session: 4­8s; “Always on” • Robust connectivity – Coding redundancy – Error detection – Selective retransmission

GPRS technology • Security – Encryption over the air – Security of core GSM network – Authentication (via SIM) – Additional authentication • Packet Switching (TCP/IP) – Automatic rerouting – Multiple concurrent users • Data latency – Variable roundtrip delays: 0.5 – 1.5s

GPRS technology • Usage based billing GPRS costs 60 R50 / MB 50 Rand / MByte 40 30 20 ­ 96% 10 R2 / MB 0 2002 2005 Year

GPRS technology • Geographical coverage – 87% of land surface – 95% of towns / population

PMR vs GPRS ☺ Excellent coverage � Good coverage ☺ Excellent reliability � Good reliability � Slow data rates ☺ High data rates � Limited capacity ☺ “Unlimited” capacity � High total cost of ☺ Low total cost of ownership ownership � Simple connectivity ☺ Robust connectivity � Poor security ☺ High security

Application of GPRS Technical considerations – Connection to the GPRS network – Conversion to IP – IP address allocation Option A – Security GPRS Network Laptop Corporate BTS BTS LAN Corporate Server Router Firewall GPRS GPRS modem modem PDA

Application of GPRS Technical considerations – Connection to the GPRS network – Conversion to IP – IP address allocation Option B – Security Corporate DMZ LAN Enterprise Corporate Internet GPRS Network Router SGSN Internet VPN/RAS Firewall Server Router GGSN BTS VPN GPRS modem Corporate Intranet Firewall Laptop PDA

Application of GPRS Technical considerations – Connection to the GPRS network – Conversion to IP – IP address allocation Option C – Security Corporate DMZ LAN Enterprise GPRS Network SGSN VPN/RAS Server Private APN GGSN BTS GPRS modem Corporate Customer Premises Equipment Intranet Firewall Laptop PDA

Application of GPRS • Technical considerations… – Support for IP • SCADA protocols vs. TCP/IP • Protocol encapsulation IP..[DNP3]..IP – IP address allocation • Dynamic vs. static IP addresses • Static IP requires private APN, VPN, RADIUS server

Application of GPRS • Financial considerations Cost Category Setup costs Monthly rental / maintenance Own Private APN and supporting R 4,500 R 5,000 infrastructure / services (50 MSISDN numbers included) Additional APN MSISDN number R8.77 / MSISDN associations APN connectivity to Corporate Application R 1,000 R 2,000 Server (64kbps) RADIUS Server R 2,850 R 3,800 Data Contract and monthly SIM card fee R200 / SIM R50 / SIM 64kbps leased line (50km) R 2,100 R 2,300 GPRS traffic charges outside of any data bundles: R2.00 / Mbyte Assumptions rd party APN access per month: R30 / MSISDN 3 Amount of DNP3 data transacted per RTU per day: 32 kbytes

Projected GPRS costs R 1,200 Own Private APN, Direct Leased line to GPRS network R 1,000 3rd Party APN, Leased line to GPRS network Own Private APN, GPRS modem connection to GPRS network Average monthly cost / RTU 3rd Party APN, GPRS modem connection to GPRS network R 800 R 600 R70 – R90 per R 400 RTU / month R 200 R 0 10 25 50 75 100 150 200 250 500 750 1,000 1,500 2,000 No. of RTUs

Role Players Power Utility System Integrator Hardware / GSM Fixed line Software Network Telco supplier Provider

Proposed Architecture DNP3 encapsulated GPRS network HLR GGSN MSC DNP3 TCP/IP APN 64kbs leased Existing SCADA SGSN BSC GSM line Master station communications server TCP/IP Own or 3 rd party DNP3 infrastructure RTU RADIUS Server APN: Access Point Name BTS: Base Transceiver Station SGSN: Serving GPRS Support Node GGSN: Gateway GPRS Support Node RTU MSC: Mobile Switching Centre BSC: Base Station Controller HLR: Home Location Register RTU: Remote Terminal Unit

Next steps • Pilot system established – Evaluate performance, reliability, risk – Determine actual cost of ownership • Recommendations for application in Eskom: – Use to supplement existing systems? – Use only for back­up communications? – Use to replace existing system? – Combination of above?

Conclusion • Features of GPRS make it an attractive option for SCADA communications • Private mobile radio: – R810 per RTU / month – R366 / MB • GPRS: – R2 / MB – R109 per RTU / month

Conclusion • Benefits: – No new telecoms infrastructure required, immediate coverage – Low operating & maintenance cost – Access to and compatibility with new technologies e.g. EDGE / 3G – Limited risk (SLAs, capacity, standby capacity) – Other applications e.g. AMR, mobile computing, prepaid vending

Conclusion SA financial and retail institutions are successfully using GPRS for EFT and credit card authorisations Will SA power utilities follow… and apply it for SCADA and other applications?