Increased equipment use, deferred capital expenditures and reduced maintenance expenses are challenges faced by most capital asset owners today. Therefore, managing critical electrical system assets such as large power transformers require a preventative maintenance plan that can screen device degradation and make intelligent device protection decisions.

Excessive heat and mechanical stress are major reasons for transformer damage. These factors can cause hot spots, breakdown of winding insulation, short circuits, and catastrophic failures. The good news, however, is that transformer failures are attributable to manageable problems and new technology in transformer protective relays enable Engineers to implement a diagnostic approach to assess the health of power transformers.

Measurable indicators of transformer health include electrical load, hottest-spot, ambient temperature, loss of life etc. Users who use protective relays to monitor these indicators, plan optimal transformer loading and maintenance, and thereby increase life of their asset and improve quality of their service.

The transformer top-oil temperature can be directly measured, or calculated from the ambient temperature, load current, and other transformer characteristics. The protective relays can be set to alarm or trip in cases where the computed hottest-spot temperature is above the pickup threshold for a user specified time (considered as transformer overheating).

Multilin relays use IEEE C57.91 compliant thermal models to calculate the winding hot-spot temperature, detect abnormal temperatures inside the transformer, and prevent loss of life of the winding insulation. The loss of life element detects the accumulated total consumed transformer life. This element can be set to issue an alarm or trip when the actual accumulated transformer life becomes larger than the user-specified loss of life pick up value.

The protective relay aging element detects the transformer aging in per unit normal insulation aging. This element can be set for alarm or trip whenever the computed aging factor is greater than the maximum permissible user-defined pickup setting under emergency loading conditions and maximum ambient temperature.

Dedicated industrial strength network

Industrial applications depend on a communications highway within the facility to ensure proper operation of both the process and electrical systems. In traditional industrial applications there are two different groups of people that are responsible to ensure the facility maintains continual operation, the Process Control Group, and the Electrical Engineering Group.

The Process and Control group is responsible for set-up and maintenance of the overall process of the facility. The Electrical Engineering group is responsible for troubleshooting problems, maintenance, and fixing the electrical equipment. Each group has their own management and control system, each with very different requirements.

Limited electrical information available to the Electrical Engineering group

In typical refinery applications, there is traditionally one communication network communicating data to both the Electrical Engineering and the Process and Control groups. Since this network is designed with the Process Control groups’ requirements in mind, limited electrical information is available to the Electrical Engineering group.

As a result, the Electrical Engineering group does not have the visibility and remote access to connected loads for essential operational information and statistics required for efficiency. Without remote access to this critical information, remote troubleshooting of electrical system problems are not possible, increasing system downtime.

The MM300 and MM200 provide dedicated communications 

With the implementation of the GE Vernova Multilin MM300 or MM200 Low Voltage Motor Management Systems, dedicated individual networks for both the Process and Control group and the Electrical Engineering group, is possible.

By having individual networks at field level devices, the MM300 and MM200 provide dedicated communications to the Electrical Engineering Group. This allows full remote access to critical electrical operation information such as; event records, data log files, motor learned data, waveform captures, operational status, full settings files, and troubleshooting.

This also provides the Process and Control group a network designed specifically for the process application ensuring maximum system response and efficiency. With the Multilin MM300 and MM200 motor management systems, simultaneous high-speed communications allow critical information to be transmit remotely, ensuring a higher level of system stability and efficiency, without compromising data integrity.

Today’s critical generation systems require more sensitive, dependable protection. Coupled with the introduction of new regulatory requirements and a focus on infrastructure security, electrical system operators need real-time access to device status and metering value data from generating units and associated equipment, to effectively manage and maximize operational output and availability.

The Multilin G60 Generator Protection System sets a new standard in Generator protection and control with streaming synchrophasor measurements, advanced protection capabilities, cyber security features and tools and support for IEC 61850 communications.

The G60 Generator Protection System is designed for any size generator application and is well suited for applications where the generator is driven by turbines such as, steam, gas or hydraulic. The G60 Generator Protection System also provides protection and control for pumped storage applications where the generator is used as both the generator and the pumping motor.

As the first Intelligent Electronic Device to provide streaming synchronized phasor measurements according to the IEEE C37.118 standard, operators are able to maximize system availability with access to captured synchrophasor data to examine machine performance, including inter-unit oscillations, during power system disturbances.

Providing the latest in cyber security, the Multilin G60 Generator Protection System includes several layers of functions and tools to maintain secured device and system access including, Dual Permission Access Control, multiple passwords, and security event alarming and reporting.

With support for IEC 61850 communications, combine the Multilin G60 Generator Protection System with the Multilin IEC 61850 HardFiber System, to create a robust and secure Process Bus Solution. Eliminate the need for miles of long distance, point-to-point copper cabling that is traditionally required to obtain measurement and I/O signal data from generators and associated system devices that are interconnected over wide geographic areas. Utilities are able to gain significant reductions in costs and effort associated with the engineering, installation and commissioning of new and retrofit generation systems while maintaining and gaining real-time access to generator status and metering values.

Integrating the Multilin G60 Generator Protection System and the IEC 61850 HardFiber System, creating a robust process bus solution for any generator station application provides detailed diagnostic information, secure control capabilities while reducing initial project capital costs and future maintenance costs.

Arcing and downed distribution conductors pose personnel and property safety threats such as fires, injuries, and even fatalities. Since high impedance (Hi-Z) faults do not produce enough fault current to be detectable by conventional over-current relays, they are not detected by traditional protection devices. Hi-Z protection in GE Vernova’s Multilin F60 is a unique, field proven algorithm incorporating a signature-based expert pattern recognition system. Harmonic energy levels in the arcing current and a sophisticated expert system assures security and dependability for detection of Hi-Z faults. This algorithm has shown a 90% success rate in detecting downed conductors based on actual in-service utility data. While traditional protection is designed to protect the power system, Hi-Z protection focuses on people and property.

Moisture ingress due to defective terminations is one of the major cause of underground cable failures. When water gathers in a subversive cable splice, a momentary line-to-ground fault occurs. Although the fault is self-clearing, the repetitive cycle of water ingress causes the splice insulation to deteriorate and in due course fail. These underground cable faults last a very short duration, which makes the design of an incipient fault protection function quite challenging The basic Multilin incipient cable splice protection algorithm detects a single incipient fault pattern. GE Vernova’s Multilin F60 uniquely recognizes the criteria that could lead to these faults, providing sufficient notification ensuring system dependability and safety. Incipient fault detection can be used either to alarm or trip. Either option is reasonable, however the occurrence of a half-cycle event indicates the cable is failing, and a full fault is about to occur in the circuit.