EGIL200 circuit breaker analyser

There are many reasons for testing circuit breakers. Some of the most important are to ensure they:

• Protect expensive equipment
• Prevent outages that lead to loss of income
• Provide reliability of the electricity supply
• Prevent downtime and darkness
• Perform as expected

There are two main types of transducers: rotary and linear. Rotary transducers are small and generally easy to mount onto the circuit breaker. However, a conversion table or conversion constant is required to translate rotary motion into linear motion. A linear transducer may be harder to mount to the circuit breaker, but it often provides a one-to-one translation of motion, so no conversion is required. The type of transducer needed depends on the manufacturer, breaker, and mechanism. Typically, a rotary transducer is required for live tank breakers. A linear transducer is most often required for vacuum, dead tank SF6, and bulk oil circuit breakers. It is best to consult the circuit breaker manual or manufacturer, but a general rule of thumb is a small linear transducer, 50 mm or less, for vacuum circuit breakers, a digital rotary transducer for live tank SF6 breakers (and some SF6 dead tank), a 200 to 300 mm linear transducer for SF6 dead tank circuit breakers, and a 500 to 600 mm linear transducer for bulk oil circuit breakers. Megger has multiple linear and rotary transducer mounting kits that you can use on various circuit breakers as well as manufacturer and mechanism-specific circuit breakers to meet all your transducer needs. Check the circuit breaker accessories guide for a list of transducers available. 

The EGIL200 has on-board memory and software that allows you to store your results directly onto the unit. Each circuit breaker is saved as a unique asset, and a record of each test will be saved under the circuit breaker. The individual breakers can be exported to software on a PC for data storage as well.

No, the EGIL is a standalone unit operated by the built-in 7-inch touch screen. You can export results to a PC for storage and analysis, but all testing is performed directly onboard the EGIL.

The TM units and the previous EGIL use CABA Win and .arc files to control the units and analyse and database results. The EGIL200 has switched to a .zip file. You can convert older .arc files through CABA Win, and you can import this file onto the EGIL, where you can view previous results and add a new test to the same file. You can also view EGIL200 files in CABA Win, but you cannot use the software to control the unit. 

The EGIL was designed with safety and simplicity at the forefront. The on-screen, breaker focussed test setup is simple and intuitive to use. The on-screen connection diagram highlights all channels in use, so you don’t miss a connection. 

The EGIL200 will measure the open and close coil currents through the control cable connection for gang-operated circuit breakers. For circuit breakers with three operating mechanisms, the EGIL will measure and graph the total coil current through the control connection but provides three independent inputs for a CT clamp to measure individual coil currents.

The EGIL is a lightweight, portable circuit breaker analyser, so a power supply is not incorporated to save weight, given the majority of times when you want to test with station voltage. When a variable voltage supply is needed, Megger has a B10E accessory that can power the circuit breaker.

The EGIL can be configured to test up to four breaks per phase and three motion channels simultaneously. If the EGIL doesn’t have enough channels to test everything at once on the circuit breaker, or you have custom test plans you want to create or work with, Megger recommends our TM line of circuit breaker analysers that can provide more advanced testing. You should note that the EGIL allows testing phase by phase, so this option can be used if there are insufficient channels on the EGIL200.

Testing should be done at various stages in the life of a circuit breaker, including:

• Development
• Production
• Commissioning
• Maintenance/fault tracing
• After service (re-commissioning)

The manufacturer typically provides a list of the parameters you should check and the range of values you should expect. The list can vary by breaker design, but if none is provided, at a minimum, you should measure the following:

• Main contact times
• Pre-insertion resistor (PIR) contact times, if present
• Max contact time difference between phases 
• Stroke
• Overtravel
• Rebound
• Velocity
• Coil current
• Station voltage
• Contact resistance

There are multiple configurations of the EGIL available, and your ideal configuration depends on the type of CBs you have and the measurements you want to perform. If you only have MV CBs to test, i.e., rack in, rack out, and vacuum type, then the EGIL211 is all you need. This configuration can test one break per phase of all three phases simultaneously and has one analogue input for measuring the travel or motion of the interrupter. As you move up in voltage levels and into transmission-type CBs, the breaker may have multiple breaks per phase and multiple operating mechanisms. The correct EGIL will need to be selected based on the maximum number of breaks per phase and the number of mechanisms your CBs have. The EGIL200 can be configured to measure up to four breaks per phase and three operating mechanisms simultaneously. If you are planning on testing transmission breakers, an option with three analogue channels and a high voltage lead kit is necessary. We also recommend opting for a minimum of two breaks per phase to ensure flexibility. The EGIL software allows for testing a CB phase by phase in case you do not have enough channels to test all contacts simultaneously. 

The hardware of the EGIL is set once it is built, so it cannot be upgraded. You can add some optional features later with software or hardware accessories. The software can be upgraded to use these additional features and accessories if the EGIL has enough channels.

With a multitude of different circuit breaker (CB) designs and manufacturers, there are many different tests that you can perform. Some tests are common to all CBs, and some design specific. Megger has an extensive set of accessories available for comprehensive testing of your circuit breaker. You can order the EGIL with different lead sets based on the breakers you will encounter. These will cover the operation of the CB, timing contacts (Main, PIR, Aux), and operational parameters of coil current and station voltage. We also recommend motion transducers and, occasionally, breaker-specific accessories based on the CB you are testing. See the accessories data sheet above for further details. 

Travel is an important aspect of a circuit breaker’s operation. With a travel curve, the overall mechanism and interrupter function is evaluated. Critical parameters such as stroke, overtravel, and rebound are recorded, and you can correct faulty operation before excessive wear or damage to the circuit breaker occurs. If you are only measuring timing, note that the circuit breaker times can be within specification whilst the velocity of the interrupter is not sufficient to extinguish the arc. For a complete evaluation of the CB, we always recommend travel measurements.

Some circuit breakers are equipped with pre-insertion resistors (PIR) for closing operations, typically on higher voltage transmission CBs or capacitor bank applications. The PIR closes first (typically 5 to 10 ms), and then the interrupter closes afterward. The PIR protects the breaker contacts from overvoltages and inrush currents. Therefore, accurate timing and measured values of the PIRs are crucial to ensure the circuit breaker is operating correctly, preventing circuit breaker failure and damage to the contacts. For a more detailed explanation of PIRs, refer to the Megger circuit breaker application guide.