Electrical equipment drives our industry and way of living, from electric drives through to the production of energy and its distribution through the grids and other systems, etc, commercial electrical equipment are dependant on electricity.
However, like all things, it comes with the risk of suffering faults which may cause harm to the user/customer, damages to this equipment, or undues downtimes to equipment. Here we take a look into common electrical faults, and how to diagnose them. We talk about solutions which involved SiC (Silicon carbide). .
- Overcurrent protection.
Overcurrents are possibly the most common electrical faults. They may be caused by something as ordinary as a overload, and serious, as a short circuit. As such, if safety devices are not in place, or compromised, catastrophic damage may be caused to cables, switchgear, transformers, and other electrical devices.
Frequent trips may be a sign of either a problem with the protection device, or a problem with the load on the circuit. Newer overcurrent protection devices often employ SiC-based MOSFETs and diodes for their efficient performance and fast-switching nature, making these part types ideal to prevent overcurrent damage in high voltage applications.
Ground Faults
Ground Fault occurs when current flows through an unintended. path to ground. Faulty insulation is often the cause for this phenomenon; current may take an unintended route back to the power source, usually through the ground,.
Diagnosis: Visual Inspection: Look for wear in cables, equipment and connectors.May expose conductors.
Ground Fault Detector: Trace which area is receiving the ground fault from this item (these detect where the current is “leaking” to ground).
Testing for Insulation Resistance: Checks if insulation is intact. Only useful for higher-voltage circuits.
SiC power devices are often used in electrical protection systems. These devices will withstand particularly high volts and temps when probing and diagnosing the ground fault detection.
Overvoltage and Undervoltage Conditions
Overvoltage is a condition of voltage in excess of the rate voltage; Undervoltage the converse, or condition of voltage falling below a supposedly “normal” level. Both can easily damage.
Diagnosis:
Measure voltage with voltmeter: Check that voltage is present at terminals of system. Compare with voltage rated of equipment for overvoltage/undervoltage.
Watch for “flashing”: A flashing of voltage means a supply that has a problem, or something may be wrong at the local grid. Use a voltage recorder to measure the “pulsations” in the voltage.
Assemble and check all protection devices: Surge protectors, regulators and so on. If none are assembled, then in additional to those necessary put in SiC type voltage protection systems.
SiC devices are especially useful for this application, being able to be rated for high voltages, and thus withstanding high volts and having produced a reliable protection for other devices, also at a high voltage. Their being able to being used (taken within the latter area) at a high voltage means an improvement in the final quality of system.Short Circuits
This is probably the most frequent and most severe of all electrical problems. A short circuit is when a conductor is unintentionally powered and takes the path of least resistance, often with corrosive, destructive results.Diagnosis:
Visual Inspection: Finding evidence of something having broken a wire or connector (burnt, has changed colour, has melted etc.) Check out the whole circuit.
Resistance Testing: Use a multimeter to measure resistance of circuit. Very low means trouble – there’s a short circuit out there.
Circuit Isolation: Isolate parts and bits of circuit, strap out etc. and read, to determine where short circuit exists.
If they don’t operate or trip, you know you have problems with your protection device!
SiC-based components are sought in this instance by reason of their low switching losses and ability to drive very high-current loads, hopefully redressing damage caused by short-circuit event. - Equipment Overheating
Overheating is common fault here, it is in reference to the electric apparatus and components in electrical systems. It’s all about parts (motors, transformers, resistors etc.) getting too hot. Caused by poor ventilation, undue loading, failure of cooling system.
Diagnosis:
Temperature Monitoring – Detection of temperature with infrared thermometer or other temperature sensor, is useful to observation of component and other things getting hot.Check for Overloading – First of all, make sure that piece of equipment is not overloaded. If so, then we know that that piece of equipment is on load, and can observe the change in temperature.
Examine: Cooling Systems – Cooling fans, heat sinks and liquid cooling systems, to include thermal pads, etc. may be checked to see that they are in proper working condition. An inadequately functioning cooling system is virtually guaranteed to create a state of overheating.
Conductivity and Insulation Testing – The electric insulating properties of that component liable to develop some sort of overheating fault due to insulation breakdown may be measured.
SiC technology for power electronic devices and systems where thermal management is critical. SiC diodes and MOSFETs possess a superior thermal conductivity and temperature handling ability, can withstand up to 300 °C
Corrosion of Electrical Contacts
Corrosion can attack electrical contacts or even just connectors which moisture, chemicals, or other environment factors can attack. This creates a higher resistance path for the overall circuit with resultant heating and power loss, or in severe cases, outright failure.
Diagnosis:
Visual Inspection: Look for green verdigris build up or white powdery dusting on connectors or cadmium terminal.
Check for Loose Connections: Loose Connections or improper torque at Connections makes these conditions very prone to corrosion. Tighten Connections and check for continuity.
Use Corrosion Resistant For Materials:Contacts and other connectors vulnerable to ingress of moisture or in corrosive environments should be made of corrosion resistant material, such as stainless steel.
Electrical Arcing
Arcing occurs when an electrical current “jumps” from one conductor to another, usually when a switch is opened and its contacts are separated, or other devices such as ers.
Diagnosis:
Visual Inspection: Look for evidence of burnt contact, common in breakers and whole switches.
Arc-Fault Circuit Interrupter or AFCI’s. These detectors sense the unique characteristics of arcing and go on interrupting the circuit, if required. You may wish to use this as a special safety add on. And do.
Switch Tests: An ordinary test for switches and whole breakers is simply switching them on and off and seeing that their make and break characteristics are correct. There should be no visible sparking or burning or other indications of broken contacts.
Classification: SiC is often a design solution in arc-fault detection and mitigation systems. SiC has a fast-switching speed and is heat tolerant.
Conclusion
You hopefully now have a few more ideas about electrical system fault and its diagnosis. Remember “proper training and education on your part are paramount in assiduously diagnosing and eliminating, before they occur, the common system bumps in the road that can, if neglected, be easily turned into bugs in the show and become an expense you can ill afford, either monetarily or in costly downtime.
