Air Insulated Switchgear (AIS) Testing
In the event of a malfunction, circuit breakers must disconnect the fault current as quickly and reliably as possible, thereby protecting all subsequent equipment. When open, they must insulate the contacts from one another and when closed, they must conduct the current as effectively as possible. In many regions of the world, such as the USA, or in regions of frequent earthquakes, the most popular high-voltage circuit breakers are "dead tank" units, whereas in other regions, such as in central Europe, "live tank" breakers are most common. In some parts of the world, both breaker types can be found.
Visual Inspections (AIS)Show more
Visual Inspections (AIS)
Visual inspections are among the most used test methods worldwide. These inspection tasks usually take a considerable amount of time due to the manual process. Test device software with integrated visual inspection tests can support the process by providing highly configurable check lists and the possibility to easily attach pictures to the final test reports.
Circuit Breaker Operation Time (In-Service) (AIS)Show more
Circuit Breaker Operation Time (In-Service) (AIS)
In-service testing methods show degradation accumulated during long idle times better than their off-service counterparts because to prepare a breaker for off-service testing, it has to be operated at least once. For the First trip test method connections are made at the trip coils and the CT’s secondary side. These test methods are very well suited to detected degraded lubricants, contaminated surfaces or corroded mechanical elements.
Circuit Breaker Operation Time (Off-Service) (AIS)Show more
Circuit Breaker Operation Time (Off-Service) (AIS)
Timing measurements according IEC 62271-100 are the most common tests on circuit breakers. These tests are used to determine operation time, pole discrepancy or pre-insertion resistor timing. The test uses a resistance or voltage threshold to measure the timing. Methods that allow tests to be performed with grounding on both sides are preferred because of the increased safety of the personnel performing the tests.
Static Contact Resistance (AIS)Show more
Static Contact Resistance (AIS)
The static contact resistance or micro-ohm measurement belongs to the most important tests on circuit breakers. The test verifies whether the resistance of the current carrying contacts, in particular the joints, allows the flow of rated current within specified losses. The resistance depends on contact surface properties which are the connection points on micro-scoping level, the contact pressure and the oxidation of the surface. Typical resistances values are between 10 to 100 μΩ.
Dynamic Contact Resistance Measurement (DRM) (AIS)Show more
Dynamic Contact Resistance Measurement (DRM) (AIS)
During dynamic contact resistance measurements, the contact resistance traces are recorded while the breaker operates. These traces deliver information about wear-related problems with the main and arcing contacts within the interrupter chamber. When the contact movement is recorded simultaneously, the length of current carrying part of the arcing contacts can be measured. Arcing contacts commonly burn off and become shorter for each interruption of current.
Coil Current Measurement and Analysis (AIS)Show more
Coil Current Measurement and Analysis (AIS)
During coil current measurement, the current signature curve of the command coils is being recorded during breaker operation. Deviations detect potential mechanical and/or electrical problems in the trip or close control components in order to prevent their emergence as actual faults well in advance, and extract information about lubrication and latch operation. This measurement can be performed online or offline.
Motor Current Measurement and Analysis (AIS)Show more
Motor Current Measurement and Analysis (AIS)
This measurement can be applied with circuit breakers equipped with a spring energy storage system and spring release mechanism. During spring drive motor current measurement, the current signature curve of the spring charging motor is recorded. The recording allows for analysis of the inrush and steady-state currents as well as the spring charging time.
Motion Recording and Analysis (AIS)Show more
Motion Recording and Analysis (AIS)
The motion or contact travel measurement verifies the operating mechanism and the mechanical linkage and can indicate potential mechanical wear. It is used to reveal the performance by evaluating the velocity of the main contacts when traveling through the arcing zone and evaluating the damping when reaching the end of the movement. Therefore, a variety of condition indicators are computed. For instance total travel, contact wipe, velocity, rebound.
Power Factor / Grading Capacitance Measurement (AIS)Show more
Power Factor / Grading Capacitance Measurement (AIS)
Measuring the power factor, or the dissipation factor, also known as the tangent delta, provides effective means for verifying the integrity of the insulation condition of circuit breaker components. In particular, the insulation condition of dead tank high voltage breaker bushings should be verified, where deterioration in capacitive layers can be detected. On life tank high voltages breakers this measurement method is used to evaluate the capacitance of grading capacitors.