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During an arc flash event, the diaphragm vibrates due to the pressurized sound wave creating a signature which is recognized by the Multilin A60. It is this unique combination of light and pressure wave detection that ensures reliable and fast detection of an arc flash event.
The Multilin A60 supports up to five sensors per unit providing optimal coverage in a typical two-high medium voltage switchgear section. To cover a larger area or for multi-section applications, Multilin A60's may be daisy chained together.
As a stand-alone unit, the Multilin A60 relay is DIN rail mountable and should be mounted inside the control cabinet of the medium voltage switchgear or motor control center. Sensors should be installed where there is a high probability of an arc flash occurring.
As the Multilin A60 utilizes both light and pressure to detect an arc flash condition, installation and wiring of external CT's are not required. An external current supervision from a separate Instantaneous Over Current (IOC) device may be used and connected as a contact input for enhanced security and mitigation of nuisance tripping.
The Multilin A60 provides an auto-calibration function for the sensors reducing total commissioning and testing time. Once installed and powered, the device will first run in calibration mode. This mode, sets the thresholds for both the light and pressurized sound based on surrounding or ambient conditions. As surrounding conditions may change, the Multilin A60 may be re-calibrated at anytime.
This figure shows the typical wiring diagram of the Multilin A60 Arc Flash System. The typical wiring diagram shows the connection of the input and output relays and the connected sources. The wiring diagram also shows the connection of the supervisory circuit (option) to the A60 unit.
This application example below describes the ability of the Multilin A60 to be deployed in a cascading configuration across multiple MV switchgear sections and compartments, including through a substation bus bar vault. The Multilin A60 sensors should be installed at a certain distance from each other to ensure coverage of the entire bus bar.
By connecting devices together using the transfer trip input/output, individual Multilin A60 devices may receive a transfer trip signal from an upstream or downstream device, ensuring fast, reliable detection of an arc flash event in large MV switchgear applications.