What is EMSA?
Electromagnetic Interference (EMI) or Radio Frequency Interference (RFI), when occurring in the Radio Frequency Spectrum, is not a new phenomenon. By definition EMI is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning. Initially the study of the phenomena of EMI was focused on the disruption of an electronic device when it was operated in the vicinity of an electromagnetic field in the radio frequency spectrum that was caused by another electronic device. One example of this type of disturbance is the static heard on a radio or television when unshielded electronic components are affected by other electronic components that generate electromagnetic fields, which was first experienced in the early days of these devices. The internal circuits of personal computers generate electromagnetic fields in the radio frequency range, as do monitor screens and television cathode ray tubes.
Later, as the voltage levels increased in distribution and transmission substations, it was discovered that radio and television performance in residences could be drastically affected by the strong electromagnetic fields associated with and generated by the electrical apparatus contained within those substations. Cordless telephones, home entertainment systems, computers, wireless security systems, medical devices, and a vast array of similar devices can fail to work properly in the presence of strong EM fields. It was determined that sharp angles, corners and edges of conductive equipment could cause RF noise to be generated. Design changes were made to greatly reduce the generation of radio frequency interference, such as gently rounded substation fittings and component shielding.
Another source of electromagnetic radio frequency signal generation is the high voltage equipment itself, such as generators, isophase bus, transformers, circuit breakers, and other related components. When an apparatus such as these begins to breakdown or fail electrically, radio frequency signals are emitted and can be detected. These signals can be captured and interpreted by trained experts who know what to look for. If left unchecked or not properly repaired, the disturbance causing the EMI signals can and often will lead to an electrical fault. Electrical faults can cause significant personal injury or death, equipment damage, and lengthy, costly outages.
It is important to note that critical electrical equipment must be properly taken out of service and maintained to ensure long service life and safe operations. Apparatus testing and system maintenance are two mutually exclusive activities which are both critically important to the overall health and longevity of electrical equipment and systems.
IMPACTS FROM OEMs
The original method for electrical apparatus and electrical system maintenance has historically involved scheduling and taking expensive outages and performing tests on equipment; cleaning; calibrating; performing needed repairs and placing systems and equipment back into service based on “best-guess” periods of time typically established by the Original Equipment Manufacturer (OEM). Unfortunately, this method of system operation and maintenance has a long history of incorrect OEM estimates, improper work practices, mistakes, and unnecessary teardowns resulting in high costs and frequent failures. This longstanding original method is known as Time-Based Maintenance (TBM) and has repeatedly been proven to be archaic and outdated with regards to predictive capabilities that can be used to prevent costly failures.
The second generation of electrical system operation and maintenance is known as Condition-Based Maintenance (CBM), which primarily calls for performing maintenance when the need arises, often based on some form of system or apparatus testing or monitoring. For example, a large power transformer has insulated bushings which are generally tested at preset periods of time (TBM). Over the years this test is repeated and the results are recorded and monitored. In the event that the bushing test results indicate some form of degradation is occurring, the asset owner/operator then can use the bushing test information to make informed decisions regarding the maintenance, repair, or replacement of the bushings (CBM).
With the advent of sophisticated monitoring sensors, fiber optics, digital relays that can communicate with one another, and numerous additional monitoring technologies, the field of Predictive-Based Maintenance (PBM) has emerged mightily in the past decade as the latest methodology related to electrical systems operation and maintenance. Predictive maintenance taps the power of the Internet of Things (IoT), big data analysis, and dynamic case management to help devices become proactive participants in their own maintenance. However, the advent of PBM has arrived at a time when other factors have caused the significant decline of qualified operators, test technicians, maintenance personnel, and engineers in the electric apparatus sector. PBM is only as valid as the analysis, interpretation, and implementation of the harvested data and the personnel performing the analysis. The margin for error remains high with PBM, as electrical apparatus has become more advanced and technical while the available resource pool of qualified personnel has dwindled. A better, more reliable system was required.
All of the above-mentioned maintenance methodologies have evolved over the past 130 years. When compared to advancements in personal computers and cell phones (which have only been in use for the past 35 years or so), the gap in advancements is startling. The electric power industry has been relatively slow in advancing new methodologies and systems when compared to the computer and cell phone industries. However, a step-change advancement in electrical apparatus and system testing has arrived.
EMSA: A GAME CHANGER
Electromagnetic Signature Analysis (EMSA) is a state-of-the-art method of testing and monitoring of electrical power apparatus – while in operation. This development is a game changer and represents a new and wide-open market that is currently in its relative infancy. In other words, EMSA represents a major step-change in electrical testing and diagnostics.
EMSA testing is performed while the facilities are at full power. No outage is necessary. No equipment must be removed from service, locked out, tagged, or grounded. There is no chance of causing an outage. There is no connection to the existing equipment. All data is collected through electromagnetic coupling. We are able to review and interpret the electromagnetic signature and identify any anomalies or incipient faults very early in their development, long before they become known problems. This method saves countless outage, maintenance, and equipment failure dollars. It does what none of the other methods can do.
EMSA testing is performed using sophisticated equipment to intercept, collect, and analyze system signals. The signals are collected using split-core Radio Frequency Current Transformers (RFCTs), placed on the neutral conductor, bus, power conduit, or other similar location that carries the system signals. The data is transmitted via coaxial cables to a spectrum analyzer device for processing and analysis. The data is analyzed by an expert and electrical system anomalies such as partial discharge, corona, arcing, sparking, and conduction are identified. Some mechanical anomalies can also be identified, such as shaft misalignment or bearing issues. The use of EMSA for large electrical power apparatus testing is primarily performed on an annual basis. A new system of constant 24-hour monitoring has been developed and it is called RMS WATCHKEEPER.
24/7 FAULT HUNTING MONITORING SYSTEM
The RMS WATCHKEEPER system takes EMSA testing to an entire new level, and it is the wave of the future. Imagine a world where electrical signature analysis is performed constantly, and unwanted electrical faults and expensive unplanned outages are avoided. The RMS WATCHKEEPER is a natural progression of electrical testing and fits right in with the IoT. The RMS WATCHKEEPER system consists of the same technology used in standard EMSA testing, but also consist of a powerful computer for onsite processing; a proprietary software to sample, capture, and analyze data; a link to the cloud for data transfer; and proprietary software with setpoints for alarm at the command center(s).
The use of advanced predictive maintenance technologies is rapidly becoming the new reality in the modern era and will save countless billions of dollars in unnecessary maintenance practices. Human safety will be improved, machine operation maximized, and overall system efficiencies will be expanded. EMSA and RMS WATCHKEEPER are becoming the new standards for electrical system testing and monitoring as continue to advance the state of technology in the electrical power industry.