Zensol's Knowledge

Our experts combine more then 40 years of experience in the measurement of High-Voltage equipment. This section's goal is to allow you to benefit from this experience. It contains articles, documents and examples that, we hope, will enable you to learn a little more.

Your contribution, comments, questions to this section are welcomed, do not hesitate to contact us.

Breaker Timing

" It is a necessity to time each breaker, in order to have its functional signature. Incorrect operation can have disastrous consequences on the equipment or the substation personnel. Not to mention the out of service losses of revenue and the repair costs... "

Maintenance for MV & HV Power Circuit Breakers

Article introduced in the Electric Energy T&D May-June 2006 Edition, demystifying the maintenance of medium to high voltage breakers. Written by Fouad Brikci and Émile Nasrallah.

Electrical Contacts in MV & HV Power Circuit Breakers

"Electrical power transmission networks are protected and controlled by medium and high-voltage circuit breakers.

Breakers are meant to make and break the flow of electrical currents in transmission lines. Being so, the electrical contact function plays a main and critical role in the breaker's proper operation.

In the present article you will find a summarized description of the different types of electrical contacts used in power circuit breakers, the major risks to their proper operation and the principal tests used to verify their condition".

Maintenance Programs for MV & HV Power Circuit Breakers

Article introduced in the Electric Energy T&D Sept-Oct 2006 Edition, exposing the advantages to follow a good maintenance program for medium to high voltage breakers. Written by Fouad Brikci and Émile Nasrallah.

Make/Break Contacts in Power Circuit Breakers

"The interruption of electric power circuits has always been an essential function, especially in cases of overloads or short circuits when immediate interruption of the current flow becomes necessary as a protective measure.

In earliest times, circuits could be broken only by separation of contacts in air followed by drawing the resulting electric arc out to such a length that it can no longer be maintained.

This means of interruption soon became inadequate and special devices called circuit breakers had to be developed".

A Thorough examination of Circuit Breaker Health

Hydro-Québec TransÉnergie explores alternative diagnostic methods in its high-voltage circuit breaker maintenance program.
" The dynamic-resistance measurement allows a precise evaluation of the wear of both the arcing and main contacts without having to open the breaker. The static-resistance measurement gives information on the status of the permanent contacts, but the wear mainly occurs on the arcing contacts, which are subjected to the heat and energy produced by arcing during each breaker operation... "

Breaker Diagnosis Examples

" The first prerequisite for diagnosing breaker troubles is to know the breaker being analyzed. Knowing the configuration of the suspect apparatus' innards, it is possible to figure out the nature of the problem by visualizing the mechanical process of the operation, in perspective with the data of the timing test.

The same is true of the experienced mechanic who can determine, at a glance, the source of the mechanical problem in a car. He knows not only automobile mechanics as a general subject, but he knows the peculiarities of the model that is brought to him... "

The Displacement Curve

" Whenever it is possible, a point-by-point measurement of the movement of the internal components of the circuit breaker, from the beginning of the movement until it comes to a complete stop, traces a curve called a DISPLACEMENT CURVE.

While the main contact timing curve gives the moment when the movement starts and the moment when the contact switches over, the information contained in the displacement curve is interesting because it allows us to follow the entire movement from beginning to end. "

Transducers Installation Examples

Consists of numerous mounting examples of different rotary transducers on more then a dozen types of breakers including ABB, Areva, GE, etc...

AC Voltage Tests

" Using the general-purpose analog inputs (channels 3 and higher) on the ZENSOL CBA-32P it is possible to measure AC voltages where the peak-to-peak amplitude is less than 10 volts. It is necessary to assemble a special circuit to obtain the desired results..."