State-of-the-Art SCADA System Returns Utility Reliability 

The SCADA sys­tem that the Lex­ing­ton-Fayette Urban County Gov­ern­ment (LFUCG) re­lied on to op­er­ate a net­work of 80 pump sta­tions and two waste­water treat­ment plants had op­er­ated re­li­ably for nearly 20 years. How­ever, time was tak­ing its toll as re­place­ment parts were in­creas­ingly dif­fi­cult to find and much of the sys­tem was ob­so­lete. Many of the ex­ist­ing SCADA com­put­ers and HMI soft­ware run­ning the plant’s mon­i­tor­ing sys­tem were old and in the need of re­place­ment. Fol­low­ing a needs as­sess­ment, LFUCG de­cided to up­grade the elec­tri­cal and SCADA sys­tems at the Town Branch and West Hick­man Creek waste­water treat­ment plants– and re­place all 80 re­mote ter­mi­nal units (RTU) at each pump sta­tion. 

Since LFUCG had several different agencies involved in the project (IT, management, operations from each plant and pump stations group, etc.) CDM Smith conducted workshops with all LFUCG stakeholders and local equipment manufacturers to learn and determine the appropriate SCADA system architecture and software needed for the project. P&ID drawings were developed from scratch to show the existing treatment plant process, combined with instrumentation and control systems which help communicate control functions between process and SCADA designers, as well as the general contractor.

CDM Smith eval­u­ated the ex­ist­ing teleme­try sys­tem; pro­vided rec­om­men­da­tions for re­plac­ing equip­ment; and eval­u­ated sev­eral pump sta­tions, the re­peater and an­tenna lo­ca­tion, and the over­all polling soft­ware/hard­ware. As a re­sult of this eval­u­a­tion, LFUCG pro­ceeded with a full de­sign for the re­place­ment of ex­ist­ing hard­ware at 80 pump sta­tion sites. As part of the de­sign, our team de­vel­oped a strat­egy so that all sites re­mained in op­er­a­tion dur­ing the en­tire switchover process.

Im­prove­ments in­cluded the use of state-of-the-art SCADA equip­ment at both waste­water treat­ment plants for re­li­a­bil­ity, stan­dard­iza­tion, and long-term main­tain­abil­ity; SCADA con­trol func­tion­al­ity for West Hick­man (the ex­ist­ing SCADA sys­tem mon­i­tored plant op­er­a­tion only); and up­grade the ex­ist­ing pro­pri­etary RTUs with a Rock­well RTU-based sys­tem and the radio com­mu­ni­ca­tion equip­ment.

The new SCADA sys­tem de­sign pro­vides mul­ti­ple ben­e­fits, in­clud­ing sim­pli­fied op­er­a­tions, hard­ware/soft­ware stan­dard­iza­tion across the en­tire or­ga­ni­za­tion, new con­trol schemes, abil­ity to eas­ily ac­com­mo­date fu­ture growth, read­ily avail­able sup­port and spare parts, and hard­ware/soft­ware flex­i­bil­ity through open ar­chi­tec­ture prod­ucts. Ad­di­tion­ally, the new sys­tems allow re­mote con­trol and ad­vanced au­to­mated strate­gies at LFUCG’s WWTPs and pump sta­tions like co­or­di­nated pump sta­tion op­er­a­tion, and im­proved staff pro­duc­tiv­ity. Other ben­e­fits in­clude con­ser­va­tion of staff time and en­ergy, im­proved re­li­a­bil­ity, en­hanced de­ci­sion-mak­ing, and storm prepa­ra­tion and re­cov­ery sup­port—help­ing pre­pare LFUCG for the next two decades of ser­vice.