After carrying out power quality review at a large electrical component manufacture, the rapid fluctuation in load means that standard Power Factor Correction equipment cannot switch fast enough to correct the PF. As such thyristor switching contactor modules were required along side de-tuning reactor to help reduce harmonics.

 

Theses newly designed FSi Fast Switching units are split into 6 stages of 50kVAr each with its own 189hZ de-tuning reactor all controlled via an 8 stage Lovato DCRG8F digital control relay specifically designed for thyristor switching.

 

As most of these new Thyristor units were replacing existing PFC equipment, we were able to reuse the existing power cables and c.t circuits. This work was carried out by 3 engineers over 3 days during normal working hours

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Above: Removal of standard FS400 Power Factor Unit and replaced with new FSi Fast swithing Thyristor unit

 

 

Above: Removal of a Standard Master/Slave PFC configuration and replaced with new FSi Fast switching Thyristor unit

 

Above: Removal of 3 Standard Master/Slave/Slave PFC configuration and replaced with new Master/Slave FSi Fast switching Thyristor units

 

Above: Removal of a Standard Master/Slave PFC configuration and replaced with new FSi Fast switching Thyristor unit

 

Power Factor replacement at a roof tile manufacturer in Gloucestershire.

After carrying out what was possible the first maintenance of the Power Factor correction equipment in the last 40 years it was found that all the capacitor banks had failed. Each capacitor stage is 100kVAr and controlled via a old volt free control relay. It was also noted that each capacitor cubicle had no solid base and the current capacitors installed were sitting on a metal grate.

After checking the contactors were still operating satisfactorily all the original capacitor assemblies were removed and replace with 100kVAa CM capacitor tray assemblies. A new solid plate was installed in the bottom of each cubicle and secured down.

The control relay was also upgraded to a new Lovato DCRL8 and was wired in a volt free arrangement as per the original install. This volt free wiring prevents any foreign voltage’s at contactors when the capacitor bank is isolated locally at the main fuse carrier.

 

 

Following a site inspection, it was found that site required a full rebuild of their 300kVAr panel-built Power Factor Correction.

We recommended replacing the existing failed capacitor tray assemblies with our own SBA 100 trays which included all new 480V rated capacitors, soft switching IMO MC62 contactors and sub fusing for all stages. This unit would be made up of 6 stages of 50kVAr and would be controlled by a Lovato DCRL8 digital control relay.

 

Our engineer completed the full rebuild in 1 day without any disruption to site and the unit was fully commissioned and left operating upon completion.

 

               

 

     

Recently a customer running a large waste recycling centre wished to move a Power Factor Correction installed in 2021 from its old site in Hartlepool to new plant in Derby, so one of our engineers attended site to remove, relocate and re-install the unit in its new location.

 

The site in Darby had a very poor power factor of 0.41 inductive and once the Power Factor Correction unit had been installed the sites PF readings were increased to a much healthier 0.99 indictive. This will now help remove the reactive charges they were receiving on their monthly electricity bills.

 

High harmonic distortion at Recycling plant.

Due to the proliferation of inverter loading at this site, concerns have been raised as to the amount of harmonic distortion being produced at this site and its potential effect on the other connected load as well as the wider effect on the MV supply to this site.

In order to determine the level of harmonic distortion present at this site as well as monitoring other power quality indices, a two week long power quality analysis was commissioned.

In addition to power quality indices, general power consumption data is presented in the form of active power (kW), reactive power (kVAr), apparent power (kVA) and operating power factor.

 

From the preceding results for this analysis it was clear that the load at this Recycling Centre operates with very high levels of harmonic distortion, high enough to distort the voltage to the point where the levels of voltage harmonic distortion exceed the G5/5 design recommendations

 

Despite the very high levels of harmonics on this supply, it will be possible to operate power factor correction at this site as it incorporates harmonic detuning reactors to prevent overload damage to power factor correction capacitors operating under such conditions.

Due to the very little additional space within the switchroom a stand alone AHF would not be possible, however the space within the distribution board allocated to power factor correction is generous and can be utilised to install harmonic filter modules that could be configured to remove the load harmonic currents and also correct the load operating power factor simultaneously.

 

With all these factors considered, a 300amp, 480volt P300-300/480 type Power Quality Filter System was installed inside of the existing LV panel along with 200kVAr of fully detuned Power Factor Correction.

All works and commissioning was carried out by 2 PFC Engineers over the course of 2 days with no interruption to sites load, with the majority of the equipment being pre-built and tested in our workshop prior to the install.