Pesce was involved in a project that was the result of very detailed tender specifications for a system to monitor and manage electrical use throughout a large campus.
The campus comprised many buildings spread across a 200ha site, including two high-voltage (33kV) incoming power substations, one central emergency power station (with generators), and 30 medium-voltage (11kV) substations, some very old and some under construction.
The overall requirement was for a programmable logic controller (PLC) based power control monitoring system (PCMS) to monitor energy usage throughout the campus and emergency generation plant status, and to provide automatic and manually initiated load shedding during the operation of the emergency power generation system.
The PCMS supplied by Pesce was engineered using the Pesce system modelling tool (Ficus). It uses supervisory control and data acquisition (SCADA) software Schneider powerSCADA Expert to gather and analyse real-time data.
This data is used to manage power use within the site and is also collated and securely sent off-site for analysis in meeting efficiency targets. The project involved detailed and thorough testing, including factory testing of new installations, local site testing at each substation, and integrated site system testing. In addition to installation and testing of the PCMS, Pesce produced manuals on the system and trained the client’s staff to operate and maintain it.
The PCMS includes the following elements:
- Generator backup systems
- Distributed intelligence and control, with local monitoring in each substation, communicating with central monitoring and the control system
- Paired redundant monitoring servers for high availability and to allow multiple monitoring by clients
- User presentation of power system status based on high-performance human-machine interface (HMI) principles, with high-level status overview and multiple levels of more detailed information for expert troubleshooting
- Monitoring of power meters, circuit breakers, contactors, ring mains units (RMU), local uninterruptible power supplies (UPS), transformers, local generators and automatic transfer switches (ATS)
- Monitoring using local signal input/output (I/O), RS485 Modbus RTU and Ethernet networks
- A distributed load shedding system to allow local substations to shed load in priority order when operating on generator power, controlled by the central controller.
This highly complex project was completed within budget in a period of two years. Complexities included scheduling, combinations of new and old installations, and the definitive specifications. Detailed scheduling was required as many factors affected the timing of works. These included multiple sites over a large area; work commencing on existing buildings before all new facilities were constructed; the need to coordinate with other contractors installing hardware and cabling; minimising interruptions to existing services whilst not interrupting emergency or security services; and requirements to give advance notice of power interruptions and testing.
The level of work required at each power substation varied widely, with new sites requiring installation and testing, while older equipment required more extensive testing, problem solving and the replacement or updating of components. Although the project specifications included informed detail, Pesce discerned that some of the requested elements were not suitable and suggested and implemented alternatives which would meet the overall system requirements.