CONDITION MONITORING OR PREDICTIVE MAINTENANCE SERVICES
Condition Monitoring or Predictive Maintenance services mainly focuses on the detection of incipient faults inside the electrical systems, which are created from gradual deterioration. The significance of a condition monitoring is in that it allows for the early identification of developing faults such as arcing before resulting in catastrophic failure.
CM of a costly and critical asset are aimed to: -Detect faults at incipient stage and avoid catastrophic faults, and -Reduce maintenance costs by doing condition based rather than time-based maintenance.
A. Condition monitoring by thermal analysis
Thermal analysis of transformers can provide useful information about their conditions and can be used to detect the inception of any fault . Most of the faults cause change in the thermal behavior of transformers. Abnormal conditions can be detected by analyzing HST (hot spot temperature) or Thermograph. The HST is one of the major limiting factors that affect the useful life of the power transformer and its loading. The HST differential is defined by industrial standards (NEMA and ANSI) for each insulation class (type and temperature rating of insulation used on windings). Obviously, the HST is the limiting temperature for a transformer’s insulation system.
Abnormal heating associated with high resistance or excessive current flow is the main cause of many problems in electrical systems. Infrared thermography allows us to see these invisible thermal signatures of impending damage before the damage occurs. When current flows through an electric circuit, part of the electrical energy is converted into heat energy. This is normal. But, if there is an abnormally high resistance in the circuit or abnormally high current flow, abnormally high heat is generated which is wasteful, potentially damaging and not normal.
Thermal imagers enable us to see the heat signatures associated with high electrical resistance long before the circuit becomes hot enough to cause an outage or explosio
B. Condition monitoring by dissolve gas analysis
Dissolved gas analysis is a traditional way for monitoring insulation condition; concentration types and production rates of generated gasses can be used for fault diagnosis. Nevertheless, the concentration of these gases increases in the presence of an abnormality (fault) such as thermal and partial discharge and arcing faults. The combustible gases are produced when insulating oils and cellulose materials are subjected to excessive electrical or thermal stresses. Multiple dissolved gas analysis tests should be taken over time so that the rate of increase of fault gases can be monitored, through which the progress of the fault can be monitored.
C. Condition monitoring by Cable Fault Location
Faults are the “natural enemy“ of reliability. A cable fault can cause an expensive unplanned outage or delay the commissioning of a new part of the network, so they need to be found and rectified quickly to enable new connections or restore the consumers’ supply. Engineers can find underground cable faults by accurately determining the distance to the fault (prelocation) and subsequently determining the exact location of the fault (pinpointing). Cable fault location on power and communication cables is a specialised area of expertise, but Megger fault locators make it simple: each instrument’s intuitive operation guides you through the fault finding process. Innovative Megger products make it possible for the user to quickly find and localise cable faults without causing damage to fault-free parts of the cable, using well-defined fault finding techniques and the appropriate test equipment.
Your benefits of Condition based Maintenance
- Reduced lifecycle costs
- Avoidance of faults and penalties
- Increased and secure energy supply
- Optimized asset performance