What it is and when you need it
Circuit breaker testing confirms that the equipment opens and closes in the correct time, with all three poles together, with contacts in good condition and with a mechanism that responds to the control voltage available. A relay can detect the fault perfectly, but if the breaker is slow or does not open, the fault is cleared by the backup, with more damage and more load disconnected.
It is done at these moments:
- Commissioning of new breakers, after installation and before energizing the bay.
- Maintenance, according to the number of operations, the currents interrupted and the time in service.
- After an anomaly: a slow trip, a pole discrepancy alarm, low gas pressure or work on the mechanism.
We test live-tank and dead-tank breakers, SF6 and vacuum, breakers in GIS and in medium-voltage switchgear, in substations and in industry. It is part of our primary equipment testing.
What is included
- Operating times Opening, closing and sequences such as close-open (CO) and, where applicable, the project’s reclosing sequence.
- Pole simultaneity and simultaneity between interrupters of the same pole. It matters because a pole discrepancy leaves a load running on two phases.
- Main contact resistance with high direct current, per pole.
- Minimum operating voltage of the trip and close coils, to know the margin they have if the battery voltage drops.
- Coil current and spring-charging motor time, when the mechanism allows it.
- SF6, where applicable Corrected pressure or density and verification of the density monitor contacts (alarm and lockout).
- Control functional checks Anti-pumping, lockouts for low pressure or discharged spring, interlocks and position indication.
- Insulation resistance between poles, to ground and across the open contacts.
How we work
- Planning. We review the factory protocol, the mechanism manual and the control drawings. We agree with your team on the lockout, the grounding points and who operates the controls.
- Safety on site. With the bay locked out and grounded on both sides, we measure using the method that suits the configuration: in GIS and in some dead-tank breakers, we measure with one ground connection lifted, or with methods that allow it, following the manufacturer’s procedure.
- Execution. Contact resistance is measured with direct current using calibrated test equipment. Timing is measured by recording the change of state of the main circuit (on opening, the separation of the arcing contacts) against the command sent to the coils. The minimum voltage is found by raising the control voltage in steps until the coil operates.
- Analysis. We compare against the factory protocol, between poles and with the previous measurement. If a value is out, we repeat and check connections before concluding.
- Report. One record per breaker with every measurement, the criterion and the result.
For gas-insulated equipment, the method differs mainly in how the poles are grounded and where measurements are taken, and always follows the manufacturer’s instructions.
Standards and criteria
IEC 62271-1 sets the common requirements for switchgear, including the measurement of main circuit resistance and the supply voltage ranges within which mechanisms must operate. IEC 62271-100 covers high-voltage alternating-current circuit breakers and IEEE C37.09 their test procedures. For medium-voltage switchgear IEC 62271-200 applies, and for GIS, IEC 62271-203.
- Timing and simultaneity: the criterion is the values guaranteed by the manufacturer in the factory protocol. There is no single value for all breakers.
- Contact resistance: compared with the factory value and between poles. An increase over the previous measurement signals wear or contamination.
- Minimum voltage: we verify that the coils operate within the control voltage range required by IEC 62271-1 and the manufacturer, with a margin against the lowest expected battery voltage.
- SF6: pressure or density and the alarm and lockout thresholds come from the breaker nameplate.
When the criterion depends on the manufacturer, the report states which document it came from.
What you receive
- A record per breaker with measured timing, simultaneity, resistances and minimum voltages.
- Timing graphs of each operation.
- Comparison against the factory values and against previous tests, if you have them.
- A list of anomalies in the mechanism or signaling, with our recommendation.
- Test files to compare at the next maintenance.
Why Tiza Group
- One responsible engineer from start to finish, from planning to the report.
- Experience in substations and industry, in medium, high and extra-high voltage, with live-tank, dead-tank, GIS and switchgear breakers.
- A protection mindset: we review the breaker with the complete scheme in mind, with its relay, its reclosing and its breaker failure function.
- Test equipment from recognized manufacturers (OMICRON, Doble, Baur, among others) for measurements that are repeatable and comparable over time.
We do field work in Colombia, or elsewhere on request. Tell us about your project.