COMMERCIAL FEATURE HEXING TRANSFORMER MONITORING SYSTEM Transformers are one the most critical components in power transmission and distribution systems; they are however prone to different kinds of faults and problems. T o reach an acceptable level of safety and reliability in operating power grids, real time monitoring of the grid is considered an essential requirement. Real time monitoring of power transformers simply means measuring and monitoring their critical electrical parameters (including voltage, current, harmonic component, power and power factor) and non-electrical parameters (such as temperature, internal pressure and oil level) on a real time basis. Adding control mechanisms to monitor systems and enabling transformer disconnect in emergency cases makes the system even more efficient. Monitoring transformers not only increases grid security but also increases a transformer’s lifespan and time between failures. Developing modern technologies such as commonly accessible and affordable telecommunication networks and easy- to-use IT systems provides opportunities for electricity distribution companies to set up transformer monitoring and protection systems. Transformer monitoring and protection systems comprise two parts: the first being the local hardware, usually a cabinet, which is installed close to the transformer and collects local signals and processes the data and undertakes remedial action in emergency situations. The second part is the monitoring and control console(s) which is located at the utility head office where utility employees monitor and control transformers in real time. Monitoring and protecting of transformers is a crucial concern for utilities; however this is not limited to transformer related challenges. In smart metering systems the installation point of transformers is a focal point where meters are equipped with telecommunication modems or programmed remotely. The telecommunication technology of smart prepaid or postpaid meters is usually short range with a collector or data concentrator unit installed near the transformer. This interface collects meter data linked to that transformer between central office and meters. Transformer monitoring and control units and data concentrators installed near the transformer make use of common components such as long range telecommunication modems. This allows for a mixture known as the ‘Smart Transformer Monitoring and Control Unit’. SOLUTION OVERVIEW Hexing’s transformer monitoring and protection system is designed to fulfil several utility requirements either as a The Hexing system is designed specifically for utility companies to act as an all-in-one solution. Factors that negatively affect transformer lifetime and shorten repair time High operating temperature (can cause oil leakage because of oil expansion): Important factors to raise operating temperature of transformers: Effective capacity (usually for delivering active energy) of transformer can be lowered by: Lack of oil Exhausted oil (causes poor cooling for oil-immersed transformers) Unbalanced three phase power Over voltage High ambient temperature Bad (low) power factor Short circuit Poor power quality and high THD (Total Harmonic Distortion) factor Overloading and short circuit 22 standalone system or integrated with existing utility systems, such as SCADA and metering systems. The Hexing system is designed specifically for utility companies to act as an all-in-one solution. The installation, maintenance and operation of all components of this transformer monitoring and protection system are made easy by its design. The system captures signals from temperature sensors, oil level sensors, signal sensors and other transceivers; measures current, voltage, energy and other electrical parameters; records and logs data and events, reports current and historical status and user data; processes captured data and sends connect/ disconnect commands to circuit breakers and isolators. At the utility head office the captured data from all transformer monitoring units can be processed using different software modules, such as: • Abnormal state analysis • Event and alarm management • Load analysis • Loss analysis • Short term load forecasting for forecasting load of transformers for the next few days SYSTEM ARCHITECTURE The number of units is equal to the number of transformers, as each transformer has its own monitoring and protection unit, thus requiring a number of units being monitored and controlled. The software system in use at the utility head office incorporates data communication with all units through public or private telecommunication networks such as fibre optics or GPRS. The Hexing system provides consoles to authorised utility employees to monitor the current state of transformers, send commands to them (such as the ESI AFRICA ISSUE 4 2014