How harmonics affect your electrical system

Beware of the trojan horse in your electrical system! 

There is a story about the citizens of Troy unknowingly bringing into their city a wooden horse that had enemy soldiers hiding inside its body. Many of the electronic and electrical devices that we use today are like that horse, and the enemy they hide inside is harmonics!

Nonlinear loads such as PCs, UPS units, VFD motors draw current in abrupt short pulses when they are switched on. These pulses give rise to distorted current waveforms that in turn lead harmonic currents to emerge within the power system.

To start with, most industrial and commercial electrical systems are designed to support around 15% more non-linear loads than their stated capacity. However, if this limit is exceeded, there is a greater possibility of harmonics emerging in the system. Harmonics significantly affects the power quality, damaging equipment and causing downtime, which translates into financial losses as well.

How harmonics harm your systems

Reduced equipment performance

Harmonics introduce high-frequency current into the system. These distortion currents can reduce the output of motors by 20%. Additionally, heating caused by harmonics degrades the motor winding. This increases the chances of failure by around 20 times and significantly reduces the lifespan of the motor.

Nuisance Tripping of Circuit Breakers

The circuits that contain inductance and capacitance have certain specific resonant frequencies. If these frequencies correspond to the harmonic frequency emerging out of non-linear loads, it gives rise to harmonic resonance. During such resonance, the voltage and current in the electrical network is highly distorted. This in turn causes nuisance tripping of circuit breakers, halting production and inducing financial losses.

Overheating issues

The emergence of harmonics leads to eddy current loss in the transformers that supply power to harmonic-producing non-linear loads. This eddy current loss increases proportionate to the square of the product’s harmonic current and its corresponding frequency.  The eddy current losses lead the transformers to heat up. Heating is also seen in cables, motors, generators, and capacitors. The heating could lead the transformers to fail. Similarly, damaged insulation due to overheating in older cables increases the possibility of fire.

Early detection is the key to preventing harmonics

Power quality issues such as harmonics are rare. They start small and quickly increase in magnitude unless detected and addressed in time. Installing power quality analyzers is a good measure to tackle harmonics. However, stationing a PQ analyzer in every corner of your facility could entail high costs. In such circumstances, digital multifunction meters could be the most cost-effective way to monitor power quality and detect PQ issues.

Explore the causes and effects of major PQ issues 

A multifunction meter is capable of monitoring a number of power quality parameters. This includes the quality of current, voltage, power factor, as well as harmonics among others.

Newtek Electricals provides durable and reliable multifunction meters enabled with MODBUS communication protocol. Newtek digital multifunction meters can record key PQ parameters and send the data to computer systems where it can be analyzed to quickly arrive at the right action.

To deliver on both safety as well as performance fronts, Newtek meters are tested in line with standards IEC 61010, IEC 61326, and IEC 60529. To make your power quality monitoring easy, efficient, and cost-effective, write to us at sales@newtekelectricals.com