SACE EMAX 2 NEW LOW VOLTAGE POWER C I RCUI T BRE AKERS TO ANS I C37 / UL 1066 / CSA STANDARDS
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— Load Shedding
Emax 2 has built-in load shedding algorithms to avoid power imbalance in the low voltage plant and stress to components.
Application examples • Grid-connected plants with running GenSets , which in addition to supporting the load during emergency conditions subsidizes the grid power by contributing to the day-to-day self-consump- tion of their loads. These systems may also in- clude renewable power sources. For example, PV-diesel remote communities connected to weak distribution-grids with many daily faults, or facilities located in areas which experience fre- quent environmental events, for example hurri- canes or earthquakes. • Grid-connected plants with back-up GenSets started up after main - gen transfer switching logics that require high reliability. For example, hospitals, banks or data centers. Benefits Emax 2 with embedded Load Shedding innovation, provides Service continuity • When a plant is disconnected from the main grid, even if local production is present, there is a sig- nificant stress that turns off all the generators re- sulting in a blackout. Emax 2 Load Shedding logics helps reduce the frequency drop that usually trig- gers a local generation protection trip, enabling a plant to maintain its live status.
Purpose ABB Emax 2 embeds patented functions based on load shedding which reduces the Microgrid stress in all situations. Typically, Emax 2 is the main pro- tection relay of the low voltage Microgrid located at the interface point with the medium voltage grid and it able to help control the plant in all situations. Microgrid in islanding operation In a standalone, the Microgrid loads remains sup- plied by the local generation, like diesel GenSet or energy storage systems when power absorption from the main grid ceases. Depending on the plan configuration, the Microgrid generation can be continuously active or started up by an automatic transfer switching (ATS) logic after a disconnection from the main grid. In the islanding transition fre- quency drop must be avoided; otherwise, the gen- eration protections could trip and jeopardize the Microgrid stability resulting with a long blackout. Emax 2, employing current and voltage measure- ments, integrates two different fast load shedding logics to reduce this blackout risk, protecting the Microgrid during the intentional or unintentional is- landing operation: • Basic Load Shedding, simple logic able to recog- nize the Microgrid disconnection event and shed a group of not priority loads thus ensuring a fast time response and power balance. • Adaptive Load Shedding, the advanced algorithm available with Emax 2 as an enhancement of the basic version. The intelligent software embedded in the unit sheds very quickly the not priority loads according to the Microgrid power consump- tion and frequency measurements. Moreover, such software has a dedicated configuration for backup generation related to ATS and the soft- ware itself is even able to estimate the energy produced by a solar plant based on plant geogra- phy settings. All the versions are available on Emax 2 platform for both the Microgrid situations, sharing some informa- tion about the loads under control in the plant.
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