|Digital Energy Protection & Control Transformer Protection|
Multilin 845 Overview
Protection & Control
As part of the Multilin 8 Series platform, the Multilin 845 provides superior, high-speed protection and control. With proven protection algorithms, the 845 provides a full range of selectively enabled protection and control elements.
Percent Differential Protection
The 845 provides enhanced security by including both restrained and unrestrained (instantaneous) differential protection. The percent differential element is based on a configurable dual-breakpoint/dual-slope differential restraint characteristic with inrush and overexcitation inhibits based on 2nd & 5th harmonics. The restraint current is calculated as a maximum of the internally compensated currents for better through-fault stability under CT saturation conditions.
The percent characteristic allows the element to account for both DC and AC saturation of the current transformers. The “cubic spline” curve characteristics enables the relay to perform accurately for restraint current in range between the two slope breakpoints.
Integrated Arc Flash Protection
The Multilin 8 Series supports an integrated arc flash module providing constant monitoring of an arc flash condition within the switchgear, motor control control centers, or panelboards. With a 2ms protection pass, the 8 Series is able to detect light and overcurrent using 4 arc sensors connected to the 8 Series relay. In situations where an arc flash/fault does occur, the relay is able to quickly identify the fault and issue a trip command to the associated breaker thereby reducing the total incident energy and minimizing resulting equipment damage.
Self-monitoring and diagnostics of the sensors ensures the health of the sensors as well as the full length fiber cables. LEDs on the front panel display of the 845 can be configured to indicate the health of the sensors and its connections to the relay.
Monitoring & Diagnostics
The Multilin 845 includes high accuracy metering and recording for all AC signals. Voltage, current, and power metering are built into the relay as a standard feature. Current and voltage parameters are available as total RMS magnitude, and as fundamental frequency magnitude and angle.
Data Logging & Learned Data
The 845 captures key electrical and DGA data values during transformer energization to trend and analyze transformer performance. Data is summarized and presented to operators through a pre-formatted Health Report to clear indication of changes to measured parameters. Up to 365 records are supported within the 845 relay. Up to 365 latest records are supported in the 845 relay. The data, when input cumulatively to the transformer model screens helps in visualizing trends and correlating key transformer electrical and DGA parameters.
Integrated Electrical and DGA for Comprehensive Transformer Monitoring & Diagnostics
The Multilin 845 offers advanced transformer health monitoring and diagnostics through advanced notification of potential issues before they become critical. The Multilin 845 features detailed learned data, summarized pre/post-fault records, and integration with GE’s DGA devices to collect, trend, and analyze a transformer’s fault gasses. This enables operators to minimize costly unplanned outages and equipment failures.