Power Industry
IMPORTANCE OF POWERLINES & TRANSFORMERS
• Electrical transmission is the process of delivering generated electricity – usually over long distances – to the distribution grid located in populated areas.
• An important part of this process includes transformers which are used to increase voltage levels to make long distance transmission feasible.
• The electrical transmission system combined with power plants, distribution systems, and sub-stations to form what is known as the electrical grid.
• The grid meets society’s electricity needs, and is what gets the electrical power from its generation to its end use.
KEY COMPONENTS OF POWER GRID
FIBER OPTIC SENSING APPLICATION
The geology/weather-induced strain, tilt, and deformation of power towers can be measured by fiber-optic sensors. The short circuit or open circuit of transmission lines may be evaluated by the measurements of temperature, icing, and galloping.
Distributed fiber-optic sensors have been practiced in most applications as well and prove to be one of the most promising sensing schemes because of OPPC/OPGW used extensively in power grids.
Two main failure causes of a transformer are electrical and thermal stresses, which can be monitored by partial discharge and the abnormality of temperature and gases, H2 typically. By Application of Fiber Optic Technology.
PARTIAL DISCHARGE MONITORING
Partial discharge is defined as a localized dielectric break- down under high-voltage stress, which bridges the insulation between two conductors. It is the main phenomenon that causes the degradation of insulation of high-voltage power transformers.
To ensure the safety of power transmission, partial discharge
measurements are an effective method of monitoring the condition of power transformers. Many investigations demonstrated the excellent characteristics of optical fiber sensor in partial discharge monitoring.
The undesirable heat radiation in the transformer weakens the insulation of transformers, which causes faults in the high probability.
The transformer losses are among the most important factors in rising of top oil and hot-spot temperature (HST). This causes rapid thermal degradation of insulation. HST, the highest temperature on the oil or winding, is the most important parameter of the transformer’s life calculation. Industry standards limit maximum allowable HSTs in transformers to 140°C with conventional oil insulation
SENSING TECHNOLOGY APPLIED IN A POWER GRID
COMPARISON
The fiber-optic sensing applications in the main components of a power grid are transformers, power
tower, and overhead transmission lines. Compared to the other sensing technologies applied in power gird,
fiber-optic sensing technology shows advantages, including immunity of electromagnetic interference, capabilities of multiplexing and distributed sensing, and tolerance to harsh environments, which has great
potential in power grids.
FIBER OPTIC SENSING BASED INTELLIGENT EARLY FAULT DIAGNOSIS SYSTEM
The intelligent early fault diagnosis system, includes Φ-OTDR-based transmission line galloping measurement, OTDR-based DTS for transmission lines and transformers as illustrated in figure above