Encon Engineers

Rolling Mill improves with Harmonic Filter

enconengineers — Sat, 28 Oct 2017 10:31:22 +0000

Rolling Mill improves with Harmonic Filter enconengineers Sat, 10/28/2017 - 16:01

Harmonic Filter for Energy Efficient Manufacturing

This Rolling Mill derived multitude betterments; solved waviness in sheet metal got rid of dc drive failures and achieved energy saving by installing harmonic filter. Waviness relates to widely placed variations in the surface texture a key quality parameter of the final sheet metal product. Mill operators reported reduced humming noise with the harmonic filtering, which was due to high-frequency harmonic currents. Harmonic reduction optimized rolling mill operation and facilitated the elimination of the coil defect, which used to cause waviness during the milling process more so with lower gauge copper sheets.

Harmonic Filter slashes energy cost and equipment footprint in rolling mill. It reduces harmonic that it generates at regeneration & improves Distortion PF. This Metal Factory in India manufactures coils, sheets and plates of copper and bronze for industrial application. It has 2nos Induction Furnaces that melt copper and zinc bar to produce copper and bronze slab. The slabs are then rolled in Hot Rolled Mill (HRM) to produce intermediary hot rolled copper and bronze coil. The coils are further rolled in the Cold Rolled Mill (CRM) to manufacture the final product of Copper and Bronze Coils of required thickness as per the client's specification. The factory has implemented an Energy Saving project by installing 2nos harmonic filter at the CRM dc drive during the year 2007.

The purpose of this performance test is to verify the real Energy Saving (in kWh tern) achieved through harmonic filtering. For that purpose It has installed 2nos 575 volts harmonic filter across its 12-pulse rolling mill DC Drives. However, as a matter of abundant caution, it is clarified that the actual energy savings ought to be seen through an installed and calibrated energy meter at the 11kV primary side of the 4.0MVA CRM transformer for a prolonged duration of time. The 4MVA transformer represents the sum total energy consumption for this rolling mill (CRM).

Harmonic Filter SLD in a Rolling Mill

While enclosing the plant's brief Single Line Diagram (SLD), the Harmonic Filter project is done for the CRM-1 load, wherein 2nos harmonic Filters are connected, one each at 575v duel secondary of the Cold Finishing Mill (CRM) transformer of rated 4.0MVA, 11kV/ 0.575 -0.575kV. The rolling mill loads, in the forms of 6-pulse DC drives, and auxiliaries are connected near equally across each 575v secondary leg of the transformer, thereby giving a 12-pulse effect at the 11kV primary of the transformer.

Mill Drive Rating: 2nos 500kW, 550V, 700- 1200rpm.

ETR (Entry Tension Roll): 2nos 265kW, 275V, 500-1800rpm
DTR (Delivery Tension Roll): 2nos 265kW, 275V, 500-1800 rpm

Payoff Reel: 1no 65kW, 400V, 500- 1800rpm

Energy and Harmonic - Measuring Principle

The total power consumption of the rolling is measured at the 11kV primary of the 4MVA transformer through its 11kV / 110V Potential Transformer (PT) and 250/ 5A Current Transformer (CT).

A high quality and internationally renowned harmonic and power quality instrument of type PowerPro is used for the power and harmonic measurement.

Harmonic Filter for DC Drives of a Rolling Mill

The field wiring is done by using a standard 3P3W connection. It is called 2-Wattmeter method for three phase power and harmonic measurement. It's used extensively for high voltage measurement. In 3P3W method, the instrument's channel-1 (Ch -1) connects to Vry and Ir and Ch -2 to Vby and Ib. The phase-b is considered common. The Phase sequence is R -B -Y in anti-clock wise direction.

The 3P3W method typically have the following rotating phase angle sequence. We first set Vry as the base or at zero angle position and all other angles are measured with respect to this base zero angle. Vry will always be locked at zero degree and thus Vby would be at -60-deg angle position.

At Unity PF, i.e. zero-deg basic angle: Ir at 30-deg and Ib at -90-deg angle.
At 0.867pf, i.e. 30-deg basic angle: Ir at 60-deg and Ib at -60-deg angle.
At -0.867pf, i.e. -30-deg basic angle: Ir at 0-deg and Ib at -120-deg angle.

The Field CT/PT connections are crossed checked to ensure that the above phase angle integrity is maintained at all measurements and load conditions.

Power Measurement - Instrument used

The Power and harmonic measurements are carried out using a high quality 3phase power quality harmonic analyzer of type PowerPro of M/s Candura Instrument, Canada. It records at a sampling rate of 256-samples/ cycle and calculates RMS value of all power parameters at every cycle. It measures all steady state power parameters, power quality including individual phase and neutral harmonics up to 64th, THDi, THDv, Inrush current, waveform and voltage and current spikes with 65uS precision. Further details of the instrument could be obtained at Candura.

Performance Test - Methodology

In consultation with the client, it is decided to measure total kWh consumption for two identical sets of coil with similar rolling pattern. It was difficult to get exactly the same set of coils. After logging data for several coil sets, we got 4sets of such similar coils and measured the relevant power, energy, and harmonic parameters. The data recording is jointly verified along with client's engineer and is presented in this performance report. The relevant details of the recorded power, energy, harmonic and waveform including energy consumption (in kWh term) data are presented here.

Harmonic Filter OFF - 4-pass rolling

Coil No K- 1012 cold rolled on12th Jan 2008 at 15.55 hrs.
Alloy 64/ 36
Initial size 0.400 x 405 mm
Final size 0.400 -0.240 -0.180 -0.135 -0.112, in 4-pass rolling
Output weight 5.33 Ton (2.1% lower sized)

Pass DTR - ETR - Kg & dc Amps Mill rpm and dc Amp Total kW & Amp (HV Meter) THDv LV THDi 11kV

One    1740kg, 216A- 1163kg, 218A       202, & 2x 129A         246   44.0A     10.2%        37%
Two       0999kg, 162A- 1001kg, 152A      301, & 2x 176A          230   32.0A                             (Ave)      (Ave)
Three    0859kg, 108A- 0672kg, 159A     350, & 2x 160A            240   28.2A
Four    0222kg, 127A- 0249kg, 120A      356, & 2x 135A         202   25.0A

Total kWh consumed in 4-pass Operation = 524.97 kWh

Harmonic Filter ON - 4-pass rolling

Coil No K- 1014 cold rolled on 12th Jan 2008 at 11.50 hrs.
Alloy 64/ 36
Initial size 0.400x 405 mm
Final size 0.400 -0.230 -0.170 -0.130 -0.110, in 4-pass rolling
Output weight 5.40 Ton (2.1% higher sized)

Pass DTR - ETR - Kg & dc Amps Mill rpm and dc Amp Total kW & Amp (HV Meter) THDv LV THDi HV

One    1610kg, 190A- 1331kg, 268A       385, & 2x 290A           430   29.0A       1.1%          15%
Two    1203kg, 197A- 1351kg, 137A       302, & 2x 200A      245   26.4A    (Ave.)        (Ave.)
Three   1019kg, 105A- 1001kg, 190A   350, & 2x 178A           230   28.0A
Four    0857kg 170A- 0877kg, 111A       403, & 2x 107A           185   13.6A

Total kWh consumed in 4-pass Operation = 494.76 kWh

Energy Savings = (524.97 -494.76)/ 494.76 = 6.12%
Diff of Coil Size rolled = 2.10%

Net Energy Saving - 4-pass rolling = 8.2 %

Harmonic Filter OFF - 1pass rolling

Coil No. P -1032 cold rolled on 13th Jan 2008 at 16.52 hrs.
Alloy 70/ 30
Initial size 0.337x 317 mm
Final size 0.253, in 1-pass rolling
Output weight 4.00 Ton (2.25% lower sized)

Pass DTR - ETR - Kg & dc Amps Mill rpm and dc Amp Total kW & Amp (HV Meter) THDv LV THDi 11kV

One 1025kg, 205A- 1423kg, 130A 204, & 2x 100A 150 and 29.6A 10.2% 40.2%
(Ave.) (Ave.)

Total kWh consumed in this single pass Operation = 83.55 kWh

Harmonic Filter ON - 1-pass rolling

Coil No. P -1028 cold rolled on 13th Jan 2008 at 16.07 hrs.
Alloy 70/ 30
Initial size 0.337x 317 mm
Final size 0.253, in 1-pass rolling
Output weight 4.09 Ton (2.25% higher sized)

Pass DTR - ETR - Kg & dc Amps Mill rpm and dc Amp Total kW & Amp (HV Meter) THDv LV THDi 11kV

One 1100kg, 215A- 1414kg, 133A 190, & 2x 120A 140 and 26.0A 1.1% 17.2%
(Ave.) (Ave.)

Total kWh consumed in this single pass Operation = 79.05 kWh

Energy Savings = (83.55 -79.05)/ 79.05 = 5.7%
Difference of Coil Size rolled = 2. 25%

Net Energy Saving -1-pass rolling = 8 %

Harmonic Filter Benefits

In-addition, further energy saving would accrue at upstream due to reduction of voltage and current harmonics starting from 575volt transformer secondary to the utility power system.

The harmonic reduction has eliminated dc drive's electronic card failure problem. In-addition equipment nuisance tripping and electrical failures are also mitigated.

By restructuring the load-end voltage and current waveform back to its normal sinusoidal shape eliminates ripple from getting into the rolling mill's dc drive bus. It enhances product quality and plant personnel have instantly confirmed the same. While cold rolling thinner grade copper sheets, earlier, there were waviness. This defect has been corrected ever since the installation of the harmonic filters. It eliminates end-product quality-check rejection and increases plant profitability.

Earlier it was not possible to operate both HRM and CRM mills at the same time due to DG capacity limitation. By reducing harmonics, filter enhances DG capacity by 20 to 30% in harmonic rich electrical environment. It enabled the client to now operate both HRM and CRM mills together with the same utility footprint of 2nos 4MW 11kV DG Set.

Due to distortion power factor (PF) from excessive rolling mill harmonics, the PF could not be maintained earlier and capacitors used to fail. The harmonic filter has substantially improved the pf and saved substantial percentage of power demand in terms of MVA saving.

Harmonic Filter Solution

enconengineers — Fri, 29 Dec 2017 13:01:09 +0000

Harmonic Filter Solution enconengineers Fri, 12/29/2017 - 18:31

Harmonic Filter Solution

Harmonic Filter solution is an engineer's approach to increasing 3P, Power, Productivity and Profitability. No stoppage. No breakdown. No quality rejection. Or for that matter, harmonic filtering reduces end-product quality rejection and in-process scrap generation by over 50% on a six-sigma scale for the manufacturing process industries. Power quality stoppages, plant breakdowns and equipment failures get mitigated by over 90%.

Cost Saving on end-product quality rejection and in-process scrap generation: There is a good reason as to why the harmonic filter solution achieves over 50% reduction in end-check product quality rejection and in-process scrap generation on a six-sigma scaling.

Energy Saving: Passive Tuned Harmonic Filter reduces a factory's net energy cost between 3% to 8% in most distortion correction projects with nonlinear loads. The energy saving in kWh term is verified by comparing the plant's energy consumption data one year before and one year after the implementation of the harmonic filter solution. Harmonic filter improves both the load power factor and the distortion PF and maintains the facility's average power factor at UNITY LEVEL consistently with variable process loads.

Equipment Failure Reduction: The most major advantage of the harmonic filter solution is that it eliminates over 80 to 90% failures and nuisance tripping problems in the facility with the electronic card, HMI/ SCADA/ Industrial Computer/ Server, variable speed (frequency) drive, dc drives, motors, and other electrical equipment.

Increases Solar Power Generation: Manufacturing industries are increasing installing photovoltaic solar power generation plants ever since solar power costing has become competitive with respect to coal-based thermal power plant's cost. There is a good reason as to why the harmonic filter achieves Extra Solar Power Generation and in-addition eliminates solar inverter's nuisance tripping problem. For a solar inverter case study please visit the web-page solar power inverter with harmonic filter.

Fully Automatic Operation with highly variable process loads: The variable harmonic filter runs without any manual interruption that including switching off while on a holiday and switching on again, once the loads restart. It allows automatic changeover between the utility power and the backup diesel generator source on a power outage and vice versa once the utility supply resume. It allows automatic reactive power control for power factor management with highly variable loads. It controls harmonics, both voltage and current harmonics, with highly variable process loads within the regulatory norm of the IEEE-519 standard.

Harmonic Filter Solution is for the Life Long: The designed Life of a high quality Tuned Passive Harmonic Filter is over 40-Years and it practically needs no-maintenance except for routine maintenance needs like occasional cleaning and tightening.

Solar Power Inverter with Harmonic Filter

enconengineers — Sun, 05 Nov 2017 13:08:01 +0000

Solar Power Inverter with Harmonic Filter enconengineers Sun, 11/05/2017 - 18:38

Solar Power Inverter

An automobile industry was facing high incident of harmonic failure in SCADA, motor drive & electrical equipment after installing 1MW solar power inverter. The rated capacity of 1.0MW DC solar power is evacuated through 16Nos, 50kW, 3Phase, 415Volts, 50Hz solar string inverter which itself got affected with the harmonic problem. While designing the solar string inverter a 20% power loss is considered by the solar panel manufacturer for conversion from DC solar panel power to AC power delivered in the 3Ph, 415V, 50Hz electrical power grid. Every day during the peak solar power generation when the sun is at the top of the sky, randomly one inverter trips and remains switched off for several hours. It causes a loss of 3 to 5% in the solar power generation by considering that the inverter trips at the most productive time. The solar power inverters diagnose it as over voltage tripping. But during the root cause analysis carried out before installing harmonic filter, we did not find any over voltage problem in the factory's electrical power system. We designed the harmonic filter for troubleshooting the factory's electrical and electronic equipment failure as well as providing a photo voltaic solar string inverter solution by mitigating its over voltage tripping condition.

Solar Panel - specification

Fig.1. Solar Power Inverter- 1mw Grid Connectivity

1. Solar panel module type: Crystallure Silicon Photovoltaic Modules

2. No of Solar Panels installed: 3100 nos
3. Solar Panel installation method: 22-deg raised angle from ground at North-South direction and the North end raised.

4. Each solar panel's Peak power delivery capacity Pmax: 320 kWp

5. Rated installed capacity in kWdc: 3100 x 320 = 992 kW

6. Average yearly generation for the total installed capacity kWdc: 17% (Estimated)

7. Open CKT voltage (Voc): 46.22 Vdc
8. Max. Power voltage (Vmp): 37.38 Vdc
9. Short Circuit current (Isc): 9.06 Amps
10. Max power current (Imp): 8.56 Amp
11. Max System voltage: 1000 volts
12. Manufacturing Standard: IEC 61215/ 61730

Solar Power inverter - specification

Fig.2. Solar Power Inverter = 64 kWdc, 3Ph, 50 kWac

1. Each Solar Power Inverter's AC power output max: 50kW, 415V, 3Ph, 50Hz
2. Total nos of outdoor inverters (IP65) installed: 16 nos

3. Max AC power delivery at the low voltage electrical grid: 16x 50 = 800 kW

4. From DC solar panel power to AC grid delivery conversion losses: 20%

5. Nos of solar panels at each DC input String: 20 panels in Series, 924.4 to 747.6 Vdc
6. Nos of DC input Strings in parallel: 10 nos, each parallel string is at 900Vdc.

7. Total Nos of Panels and kWdc at each solar Inverter: 200 solar panels x 320 kW= 64 kWdc at each Solar Inverter.

8. DC input: 200 to 1000 Vdc (max), MPPT= 520 to 800 Vdc

9. DC Short Time current Max: 2x 50 Amp
10. DC Short Circuit current: 2x 60 Amps

11. Solar Inverter AC Power Output: 3P3W or 3P4W, 50/60Hz, Normal: 50 kW/ 50 KVA, Max: 55 kW/ 55 KVA and Imax: 80 Amp

Solar Power Inverter - Grid Connectivity

Each solar string inverter is connected with 200 nos solar panels each of 320 Wdc capacity. Totally the solar inverter collects 64 kWdc power at its input and converts it into 3Ph, 50Hz, 50 kWac power at its output as shown in Fig.2. The main ACDB is connected with 16 nos solar inverters wherein all are paralleled. Totally it connects to 3Ph, 50Hz, 800 kWac power load as shown in Fig.1. Finally the main ACDB is connected at the 2500KVA, 22kV/ 0.415kV transformer's main LV PCC panel with a 2000A, 415V ACB for total 800 kWac power delivery at the factory's electrical power system.

Fig.3. Solar Power Inverter Energy Generation Profile

Ever since the installation of 1.0 MW solar plant, this automobile factory had started facing substantial increase in nuisance tripping and failure in electronics, drives and electrical equipment.

While carrying out harmonic audit we observed that the total current harmonic distortion (THDi) at the 415V main incomer of 2500KVA transformer-2 was at 40% and the total voltage harmonic distortion (THDv) was at 10%. The current harmonics coming from the 1.0 MW solar plant, which is connected at the downstream of the transformer-2, was at 11.6% during full solar power generation period when the sun is at the top.

Harmonics apart, it caused stressful power quality problem. The transient voltage fluctuation and voltage sag recorded was at an unacceptable level of 17.7% and the transient current fluctuation was at a dangerous level of 100% rise over its steady-state base load. Harmonic failure apart, it increased end-product quality-check rejection and also increased scrap generation from the manufacturing process.

Fig.4. Solar Power Inverter - Harmonic Filter

A 1407A Encon Harmonic Filter is installed during Nov. 2017 at the 415V main incomer PCC of 2500KVA transformer-2. It's designed for the full transformer-2 load including the 1.0 MW solar power harmonic at the downstream of transformer-2. Passive harmonic filter being a harmonic absorption type, engulfs harmonics from both downstream as well as upstream within its range.

Without the harmonic filter, a portion of the current harmonic circulates and gets absorbed within the plant equipment, and the other portion flows back to the upstream power grid. Since the electrical and electronic equipment in a plant are not designed for the high frequency harmonic currents, plant equipment get overloaded and trip many a times. In its dormant stage the harmonic injects energy losses. The higher current harmonics within the plant equipment create higher voltage harmonics which in turn generate further current harmonic.

Thus, the current harmonic increases with the increase in non-linear-load within the same transformer. This is the root case why the addition of 1.0 MW Solar Plant in transformer-2, substantially increased the nuisance tripping, failure and reject scrap generation in this automobile industry. Summarily, it increased both current and voltage harmonics within the transformer's electrical power system wherein the plant equipment are connected.

With the commissioning of the harmonic filter, the current harmonic got slashed from 40% to 6% and voltage harmonic got reduced from 10% to 2% level. This harmonic reduction case study is delineated in an another web page, please read it at Passive Harmonic Filter.

Fig.5. Solar Power Inverter Current Harmonic Distortion

Even though the solar plant was connected at the downstream of the transformer-2, as reasoned above, the current harmonic generation from the solar power inverter got reduced from 11.6% to 4.6% at full load, as shown in Fig.5. A typical day's energy (kW) generation profile from this 1,0 MW solar plant, after the installation of harmonic filter, is shown in Fig.3.

The harmonic filter is connected at the 415V main incomer of 2500KVA transformer-2 is shown in Fig.4. The harmonic filter has eliminated the daily harmonic problem of nuisance tripping with solar power inverter. And together by slashing it's harmonic generation it is expected to increase the overall solar plant efficiency and enhance its power generation capacity in kWh terms by 8%.

Within a few days after commissioning the Harmonic Filter at this automobile industry, we were interacting with the shop floor electrical supervisor. He informed us that in the previous night while he was on a night shift duty the plant lights dimmed due to grid voltage fluctuation. From his experience he knew that it's going to be a bad day and invariably the big machines, the Inter-Mixers with 400kW VFD drives, would trip and along with it there would be several tripping in the process lines involving several VFD drives, HMI and SCADA. As usual he ran towards the Inter-Mixer Drives and his other team members ran towards other process areas. He and his team members are the first line of defense against voltage sag tripping. He was surprised and was wondering why nothing has tripped? For this good reason we describe Encon harmonic filter as an Electrical Fly Wheel. It's designed with energy storage devices and those are very useful in mitigating momentary voltage sag. Over the past 25-years we have learned that 80 to 90% nuisance tripping get eliminated after installation of Encon Harmonic Filter. That apart, by slashing harmonics, both voltage and current, it eliminates 80 to 90% failures with electronics, drives and electrical equipment.

Corporate Building fixes UPS and Elevator problem

enconengineers — Mon, 30 Oct 2017 10:38:05 +0000

Corporate Building fixes UPS and Elevator problem enconengineers Mon, 10/30/2017 - 16:08

Intelligent Building eliminates UPS and Elevator failure

How to troubleshoot the extraordinary equipment failure, electrical fire and occupants' safety issue in a building? Read this case study how building harmonic filter fixes light flicker & UPS tripping with grid voltage fluctuation. How harmonic causes electronic card failure and creates trouble with elevator operation. The quality of the incoming power supply from the utility grid carries crucial performance parameters for the building equipment.

Why UPS fails to mitigate incoming voltage fluctuation

Though it's not at the hand of building engineers, they have engineering tool to condition the incoming power quality. UPS powers critical building loads, namely work station computers, corporate data center servers and emergency lighting. Many wonders why sensitive equipment powered by UPS fails on voltage fluctuation? Why emergency lighting at the UPS output supply flickers on grid voltage dip? UPS is not a power conditioner but more of a convenience. It can only condition the steady-state voltage profile. UPS can't mitigate momentary voltage transient and power surge, which typically lasts in milliseconds, and passes those to output supply in the form of DC ripples.

Building's power quality problems and how to improve it

Murugappa Group is South India's largest business conglomerate. Its corporate office is a 6-story heritage building built-in 1932 (dare house) and extended in 1950 (parry house and dare house extension). Its total area is 250,000 Sq.Ft. It accommodates 1300 corporate employees. The group has diverse business activities in engineering, finance and leisure sectors; namely automobile, abrasive, OEM component manufacturing, fertilizer, sugar, food, finance, insurance, travel and tourism. Two nos dry-type transformers, each 1250kva, 11kv/415v, power the building through two LT PCC each in double bus bar configuration and one harmonic filter as shown in Bus Sec-1 SLD. The capacitor APFC panels removed after installation of harmonic filter which apart from controlling harmonics and troubleshooting failures, maintained PF at 0.99, consistently.

The quality of power, which lies in momentary transients, does not better with the installation of UPS. Triplen filter is the engineering tool build for mitigating the momentary power surge, be it voltage fluctuation, unbalance, high neutral current and neutral voltage. In this building, 3x60kva UPS in parallel powered the corporate data centre servers for pan India and global operation, and 2x60kva UPS in parallel powered the work stations. Electronic cards, SPMP and hard disk drives were failing from bad power-quality. A Sudden dip in utility grid voltage used to cause flicker on floor lighting and simultaneously trip UPS incomer main supply breaker/ MCCB. When the main building supply is uninterrupted but the UPS incomer trips; it's both tricky and alarming. UPS battery drains out in 30 to 40 minutes unless at every trip someone notices it and switches on the circuit breaker at the UPS incomer. Building automation is not fool-proof against bad power-quality. Elements of the SCADA system hangs and needs a reset.

By creating a bonding through an intertwined magnetic flux path, Triplen filter not only equalizes three-phase currents and voltages but opposes any change of power system parameters from the equilibrium state. It prevents sudden voltage variation and conditions the quality of incoming power supply by eliminating transient surges, improving three-phase unbalance and removing neutral current and neutral voltage. We installed one 120A/phase and 240A/neutral Triplen filter at the main incomer of 3x60KVA Data Center Server UPS and another 80A/phase and 160A/neutral Triplen filter at the main incomer of 2x60KVA workstation UPS. It mitigated the lighting flicker whose dimming intensity (dip in Lux level) and frequency of occurrence reduced substantially. The UPS tripping problem got eliminated. Besides, the building's total neutral current at 1250kva, 11/0.415kv transformer at 415V Main MV Panel got reduced, triplen filter removes neutral current by 70 to 90% depending upon the fault level of the electrical power system.

Elevator problems a building face and how to solve it

The building has over half a dozen guest and service elevators, installed from diverse OEM companies. It was facing a series of extraordinary elevator problems and failures.

1. It randomly malfunctioned, went to the wrong floor.
2. It had repetitive burn out issues with Electronic Components, Circuit Boards, Relays and PCB Cards.
3. The automatic lift door got jammed or slammed shut.
4. The elevator's floor landing was not in alignment with the floor level.
5. It had frequent breakdown problem wherein it used to get stuck in an arbitrary position trapping occupants inside. Often, it used to happen after a power failure or while experiencing a brownout condition.

One may be curious to know why modern buildings which employ automated building management solutions and smart elevators, can't achieve self-resetting with elevator operation? Well, elevators restart pretty efficiently on a sudden power outage that remains off for a length of time, typically 20 seconds. But in case of a brownout situation the incoming voltage sags or slumps. It spikes the current drawn by critical and expensive elevator electronics and electrical equipment, which could lead to failure. For the elevator manufacturer, there is a trade-off between equipment safety and excessive nuisance tripping. Crossing the threshold, the elevator's electrical protection system passes on to assisted reset mode with three options.

1. Power system reset wherein a simple power on and off does the job and the elevator comes back to service.
2. Software reset involves a software corruption that requires OEM service team to reset or reload the software.
3. Breakdown reset involves a complex scenario wherein the manufacturer's knowledgeable technician inspects and replaces the faulty components before restarting the elevator.

We installed one elevator triplen filter, 10A/phase and 20A/neutral, for each affected elevator at its main power incomer in the lift room. It resolved all elevator issues.

How to assess Electrical Fire Risk and its prevention measures

When it comes to electrical fire risk assessment of a building, there arise six questions which determine the correlational root cause analysis of the fire incident.

1. How did the electrical fire seem to have ignited?
2. Where, in the building, the fire started first?
3. Did the fire spread too quickly, if yes, why so?
4. Did the fire start from multiple locations in the facility?
5. Did the fire originating spot(s) have high energy intensity load(s)?
6. Is this a sophisticated, intelligent building with modern gadgets or a conventional building?

Once we have sufficient answers and clarity on the first two questions, the likely reason for the fire is simple, either worn out installation or negligence. The possible causes could include worn out or undersized electrical wiring, faulty electrical receptacles switches or outlets, weary appliances, worn-out light fittings or unrestricted use and haphazardly placed extension cords or loosely connected gadgets.

If, however, the questions are beyond the first two, the reasons could be varied, and only an experienced electrical engineer can get to the bottom of the problem and troubleshoot its further recurrence. Nonetheless, attributing electrical short circuit as a cause for every building fire is an invention of the press, television and entertainment media, social media and newspapers. The probability of an electrical short circuit fire is pretty low, anyway. High neutral current is a major-reason for igniting an electrical fire, anywhere in a building, at multiple locations along with the building's electrical power system. It's a technological fire incident. The modern and high tech buildings are not only susceptible to it but their sophisticated electrical and electronic gadgets and LED lights generate triplen harmonics which triple at neutral and create a high neutral current. Triplen harmonic filter by removing the neutral current from the building's electrical power system, greatly-eliminates the electrical fire risk.

Harmonic Filter an extraordinary troubleshooter for building

Following the collapse of several grid sections in India, TNEB, a local utility company has mandated limiting harmonics starting 2012 as per Govt of India's "CEA regulation 2007 for grid connectivity" which in turn is as per IEEE 519 standard. It is difficult to deconstruct the root cause of a grid collapse. Even after decades, no convincing reason has emerged from the American grid collapse. Grid collapses when multiple reasons swell-up cascading one after another and reach the threshold trigger point.

Power quality harmonic is a predominant specification that defines a stable grid. It prevents the grid from a sudden collapse by relieving it together with connecting generating stations from the cascading effects of a possible built-up of a stressful power system condition. Furthermore, electrical harmonics are unpredictable, and under a favourable power system impedance, trigger harmonic resonance magnifying harmonics, voltage fluctuations and power surge.

Building harmonic filter increases maintenance efficiency and enhances building valuation by extending asset life by eliminating failures in HVAC motors, VFD drives, Switchgears, LED lights, SMPS, UPS input cards, Lift (Elevator) VFD cards and Electronic gadgets. The harmonic filter replaces capacitor APFC panel which anyway has a short life besides it magnifies harmonics. The Total Current Harmonic Distortion (THDi) and Total Voltage Harmonic Distortion (THDv) was 20% and 7% respectively at Bus Sec-1 with high waveform distortions during the initial harmonic measurement in 2012. The harmonic filter mitigated both THDv and THDi within acceptable limits of IEEE 519 standard and reconstructed both voltage and current waveforms back to sinusoidal. Besides, the harmonic filter project eliminates the need for equipment derating and removes barriers to energy efficiency, which saves equipment footprint and energy consumption for the building.