Protection Relays
Whatever your utility’s protection requirements are, whether basic redundant IEEE 1547 settings, directional/reverse power restrictions, regional ISO under/over voltage or frequency, loss of phase detection, phase or ground over current, or other ANSI functions, Day Ahead makes relay assemblies to meet your needs.
In addition to the ANSI protection functions, a Day Ahead relay assembly will come with any and all of the balance of system features –test switches, DC UPS, internal overcurrent protection, appropriate NEMA enclosure, status light, I/O terminal strips, engraved labeling, etc.– necessary for a turn-key installation that is fully compliant with your utility’s specifications.
RTU
For PV systems in the megawatt range, even for roof top applications, utilities may require real time monitoring and reporting of power generation per the recommendations of IEEE 1547.3 IEEE Guide for Monitoring, Information Exchange, and Control of Distributed Resources Interconnected with Electric Power Systems. This communication is accomplished using remote terminal units (RTU) communicating directly with the host utility’s energy management systems (EMS). Day Ahead Instrumentation manufactures the ready-to- install assemblies. Strategic Partner NEO Virtus Engineering can provide integration and design services for the RTU hardware and peripherals or provide support to the project’s engineering team. As part of the process NEO configures the RTU communications to meet the host utility’s standard with the specific network and IP addressing provided to the customer by the utility.
Communications
Typical communications in the PV system include:
• Data transmission amongst customer PV DAS, protection relay, metering and customer SCADA
• MPLS line communication between the PV system RTU and Utility EMS
• Communication among multiple PV arrays inside the PV system
• Direct Transfer Trip (DTT) from utility to relay and interrupting device
• Communication between the PV system protection relay and non-PV Co-Generators on site
The communication system is often a mix of infrastructures –fiber optics, copper-wire line, power line communications and wireless technologies. Various protocols are required to establish successful communications among different equipment or to be integrated with the existing communication system, all with the goal of satisfying the utility’s specifications.
CTs, PTs & Balance of System
Day Ahead can provide pre-wired solutions for medium voltage and low voltage current and voltage transformers assemblies for pad mount or substation applications. DAI has ground fault and arc flash detection systems for integration into your relay. Utility grade station battery systems are available for substation DC uninterruptable power sources for any required loads and uptimes.
Remote Site Monitering
Day Ahead has the capability to design, manufacture, and program instrumentation suites for any application. We have extensive experience in both remote monitoring systems and instrumentation which is integrated into existing SCADA systems. The monitoring station at the Jakobshavn Isbrae Glacier, Ilulissat, Greenland (photo on right) is an example of PV and wind instrument power and power management provided by Day Ahead Instrumentation. (Photo courtesy New York University’s Courant Institute of Mathematical Sciences.)
