Full Bridge Unified Power Quality Conditioner Applied In Single Wire Earth Return Electric Power Distribution Grids

(1)

_____________________________________________________________________________________________

ISSN (PRINT) : 2320 – 8945, Volume -5, Issue -3-4, 2017 7

Full Bridge Unified Power Quality Conditioner Applied In Single Wire Earth Return Electric Power Distribution Grids

Vivek Kumar, Dr. G. K. Banerjee

Department of Electrical Engineering, IFTM University, Moradabad

Abstract -

This paper deals with the involvement of three-phase four-wire (3P4W) electrical power distribution system (EPDS) available locally, using a single- to three-phase unified power quality conditioner (UPQC) topology, called UPQC-1Phase-to-3Phase. The topology is indicated for applications in countryside or remote areas in which, for economic reasons, only electrical power distribution systems (EPDS) with single wire earth return are handy to the consumer. Since the use of three-phase loads is increasing in these areas, right of entry to a three-phase distribution system becomes preponderant. By adopting a dual compensation strategy, the proposed UPQC-1Phase-to- 3Phase is capable of draining from the single-phase electrical grid a sinusoidal current and in phase with the voltage, resulting high power factor. Additionally, the system is also able to restrain grid voltage harmonics, as well as to compensate for other disturbances, such as voltage sags. Thus, a 3Phase, 4Wire system with regulated, balanced and sinusoidal voltages with low harmonic contents is provided for single- and three-phase loads. An analysis of the power flow through the series and parallel converters is performed in order to aid the designing of the power converters. Experimental results are presented for validating the scheme, as well as evaluating the static and dynamic performances of the projected topology

Keywords: Power Quality (PQ), Unified Power Quality Conditioner (UPQC), Electrical power distribution systems (EPDS).

1. INTRODUCTION

Electrical power distribution systems (EPDS) with single-wire earth return (SWER) have been commonly adopted as a solution for electrical power supplying. This is due to the fact that the reduction of costs in the distribution of energy to serve large territorial extensions with low demographic densities is an important requirement, since lower installation and maintenance costs are achieved.Other alternatives are the use of energy distribution by means of two conductors (phase-to- neutral) without earth return or even using two-phase systems (phase-to-phase). Considering these alternatives, capital investments for the realization of

SWER distribution grid facilities installations are still lower.

The electric power system is considered to be composed of three functional blocks - generation, transmission and distribution. For a reliable power system, the generation unit must produce adequate power to meet customer’s demand, transmission systems must transport bulk power over long distances without overloading or jeopardizing system stability and distribution systems must deliver electric power to each customer’s premises from bulk power systems. Distribution system locates the end of power system and is connected to the customer directly, so the power quality mainly depends on distribution system. The reason behind this is that the electrical distribution network failures account for about 90% of the average customer interruptions. In the earlier days, the major focus for power system reliability was on generation. and transmission only as more capital cost is involved in these. In addition their insufficiency can cause widespread catastrophic consequences for both society and its environment.

But now a day’s distribution systems have begun to receive more attention for reliability assessment.

Initially for the improvement of power quality or reliability of the system FACTS devices like static synchronous compensator (STATCOM), static synchronous series compensator (SSSC), interline power flow controller (IPFC), and unified power flow controller (UPFC) etc are introduced.

These FACTS devices are designed for the transmission system. But now days more attention is on the distribution system for the improvement of power quality, these devices are modified and known as custom power devices. The main custom power devices which are used in distribution system for power quality improvement are distribution static synchronous compensator (DSTATCOM), dynamic voltage Restorer (DVR), active filter (AF), unified power quality conditioner (UPQC) etc.

In this work from UPQC has been used with PI controller for the power quality improvement in the distribution system. Here two different loads are considered, one is linear load and the other is induction motor. Different fault conditions are considered with these loads in order to analyze the

(2)

_____________________________________________________________________________________________

operation of UPQC to improve the power quality in distribution system. The important factors to be considered in power quality measurement are the active power, reactive power, variation of voltage and current, flicker, harmonics, and electrical behavior of switching operation [1]. According to definition of power quality given in IEEE standard,

“Power quality is the concept of powering and grounding sensitive equipment in a manner that is suitable to the operation of that equipment. Serious problems in electrical systems is the increasing number of electronic components of devices that are used by industry as well as residences and increasing use of nonlinear loads is the main cause for increased harmonics in voltage, current[2][5].

In recent years, the development of power electronics devices has been led for the implementation of electronic equipment which is suitable for electrical power systems[3]. These types of devices allow great flexibility in: a) controlling the power flow in transmission systems using Flexible AC Transmission System (FACTS) devices, b) enhancing the power quality in distribution systems employing Custom Power devices[6][9]. The harmonic current components create several problems like,

1. Increase in power system losses 2. Over heating and insulation failures in transformers, rotating machinery,conductor,and cables

3. Reactive power burden 4. Low system efficiency 5. Poor power factor

6. System unbalances and causes of excessive neutral currents

7. Malfunctioning of the protective relays and untimely tripping.

One of the effective approaches is to use a UPQ Cat point of common coupling (PCC) for the protection of sensitive loads. It is a combination of shunt and series active power filters, sharing a common dc link as shown in Fig.1. It is the only versatile device which can easily mitigate many power quality problems related with voltage and current simultaneously. It also compensates almost all power quality problems like voltage harmonics, voltage unbalance, voltage flickers, voltage sags &

swells, current harmonics, reactive current, current unbalance, and can also be used to prevent harmonic load current from entering into the power system [10].

Fig.1.Unified Power Quality Conditioner UPQC consists of two IGBT based Voltage source converters (VSC), one shunt connected active filter and one series connected active filter cascaded by a common DC link. The shunt APF provides VAR support to the load and supply harmonic currents to prevent it from entering into the power system. When ever the supply voltage undergoes sag then series APF injects suitable voltage with supply and can compensate all voltage related problems such as voltage harmonics, voltage swell, flicker etc.[8].

Thus UPQC improves the power quality by preventing load current harmonics and by correcting the input power factor

2. UNIFIED POWER QUALITY CONDITIONER

The Unified Power Quality Conditioner is a custom power device that is employed in the distribution system to mitigate the disturbances that affect the performance of sensitive and/or critical load [3]. It is a type of hybrid APF and is the only versatile device which can mitigate several power quality problems related with voltage and current simultaneously therefore i t is a multi-functioning device that can compensate various voltage disturbances of the power supply. It can correct voltage fluctuations and prevent harmonic load currents from entering the power system.

Fig.2.UPQCgeneralblockdiagram

(3)

_____________________________________________________________________________________________

The system configuration of a single-phase UPQC is shown in Fig.2. Unified Power Quality Conditioner (UPQC) consists of two IGBT based Voltage source converters (VSC), one shunt and one series, cascaded by a common DC bus. The shunt converter is connected in parallel to the load. It provides VAR support to the load and supply harmonic currents.

When ever the supply voltage undergoes sag then series converter injects suitable voltage to the supply [3].Thus UPQC improves the power quality by preventing load current harmonics and correcting the input power factor. The main components of the UPQC are series and shunt power converters, DC capacitors, low-pass and high-pass passive filters, and series and shunt transformers.

The main purpose of a UPQC is to compensate for supply voltage power quality issues, such as, sags, swells, unbalance, flicker, harmonics, and for load current power quality problems, such as, harmonics, unbalance, reactive current, and neutral current. The key components of this system are as follows.

1) Two inverters, one connected across the load which acts as a shunt APF and other connected in series with the line as that of series APF.

2) Shunt coupling inductor L is used to interface the shunt inverter to the network. It also helps in smoothing the current wave shape. Sometimes an isolation transformer is utilized to electrically isolate the inverter from the network.

3) A common dc link that can be formed by using a capacitor or an inductor. In Fig.1, the dc link is realized using a capacitor which interconnects the two inverters and also maintains a constant self- supporting dc bus voltage across it.

4) An LC filter that serves as a passive low-pass filter (LPF) and helps to eliminate high-frequency switching ripples on generated inverter output voltage.

5) Series injection transformer, that is used to connect the series inverter in the network. A suitable turns ratio is often considered to reduce the voltage and current rating of series inverter.

In principle, UPQC is an integration of shunt and series APFs with a common self-supporting dc bus.

The shunt inverter in UPQC is controlled in current control mode such that it delivers a current which is equal to the set value of the reference current as governed by the UPQC control algorithm [7].

Additionally, the shunt inverter plays an important role in achieving required performance from a UPQC system by maintaining the dc bus voltage at a set reference value. In order to cancel the harmonics generated by an onlinear load, the shunt inverter should injecta current. Similarly, the series inverter

of UPQC is controlled in voltage control mode such that it generates a voltage and injects in series with line to achieve as inusoidal, free from distortion and at the desired magnitude voltage at the load terminal.

In the case of a voltage sag condition, actual source voltage will represent the difference between the reference load voltage and reduced supply voltage, i.e., the injected voltage by the series inverter to maintain voltage at the load terminal at reference value. In all the reference papers on UPQC, the shunt inverter is operated as controlled current source and the series inverter as controlled voltage source except that the operation of series and shunt inverters are interchanged. For enhancement of power control now a day we use fuzzy logic controller or artificial neural network instead of PI controller.

3. RESULT AND DISCUSSION OF UPQC

The performance of the proposed UPQC is evaluated under Matlab/Simulink. Under normal conditions, three-phase voltages and currents are sinusoidal but when we are using nonlinear load, then it generates harmonics at a high distortion level. UPQC is expected to compensate the harmonics produced by nonlinear load (diode rectifier feeding an RL load), eliminate voltage sags and provide reactive power compensation at PCC.

The results demonstrate the effectiveness of the proposed UPQC. Shunt APF generates harmonic content of the load current but with opposite polarity such that when they are injected at the point of common coupling the harmonic content of supply current is effectively reduced and this reduced value remains constant by using discrete PI controller.

To validate experimentally the UPQC-1Ph- to-3Ph, intended to feed single-and three-phase loads from the SWER Power Distribution Systems, commonly found in rural and/or remote areas and suffer with power quality problems, the dual compensation strategy is adopter. The proposed UPQC-1Ph-to-3Ph makes possible to drain from the single-phase electrical grid, a sinusoidal current in phase with the grid voltage. Furthermore, the system can also suppress harmonics from the grid voltage, as well as compensate for voltage related disturbances, such as voltage sags/swells.

The topology of the UPQC-1Ph-to-3Ph is such that this is formed by two PWM converters, One being a Full-bridge inverter and The other is a split- capacitor 3-Leg inverter sharing the same dc-bus. As

(4)

_____________________________________________________________________________________________

can be noted, a half-bridge inverter is used to design the series converter. Thus, besides using one leg less compared to the topology presented, the dc-bus is formed by the split-capacitor configuration, allowing access to the earthed return conductor of the load, as well to be used in SWER Distribution Systems. As can be noted, the four-wire of the load is connected to the dc-bus central point.

The series converter, also called SAPF, is current controlled so that the input drained current is sinusoidal and in phase with the grid voltage, resulting in a power factor (PF) very close to one. A filter inductor ( ) is placed in series with the primary winding of the single-phase series coupling transformer.

Fig: 3 Block Diagram

Fig.3, shows The block diagram of a typical UPQC- connected distribution system, where the UPQC consists of essentially a series-connected injection transformer, a voltage-source inverter, an inverter output filter, and an energy storage device that is connected to the dc link.

Fig.4. Structure of UPQC-DVR

The energy storage unit is directly connected to the DC line and it’s responsible for energy storage

in DC form. When UPQC is used for compensation, it only supplies the required power of the system.UPQC has a large dc capacitor to ensure stiff DC voltage input to inverter. A PWM inverter is used to convert & store DC to AC form. It generates sinusoidal wave signals by comparing a sinusoidal wave with a saw tooth wave and sending appropriate signals to the inverter switches. By pass switch is used to protect the inverter during the faculty conditions from high currents.

The inverter output must be filtered by the filter circuit before injecting to the system so that harmonics due to switching function in the inverter are eliminated. When UPQC is used for compensation, the injection transformer will be connected in parallel with a bypass switch. When the system voltage drops (voltage sag) at the fault condition, the UPQC device injects a series voltage (VDVR) through the injection transformer so that the desired load voltage magnitude can be maintained, The injected voltage of the DVR can be expressed as

S L L L

DVR

V Z I V

V   

……… (1)

Where,

VL – Load voltage ZL – Line impedance

IL – Load current and VS – Source voltage at fault condition.

Fig.5. Phasor diagram of fault electrical conditions during voltage sag.

Phasor diagram of fault electrical conditions during voltage sag is shown in the fig.5. Voltages,V1,V2 , and VDVR are the source-side voltage, the load-side voltage, and the DVR injected voltage, respectively.

(5)

_____________________________________________________________________________________________

Also, the parameters I,

 ,  and 

, are the load current, the load power factor angle, the source phase voltage angle, and the voltage phase advance angle, respectively.

DVR S

L

V V

V  

………. (2)

Fig.6. Phasor diagram of in-phase DVR compensation

In the in-phase compensation method, we have to make, VS = VL = VO, where VS – source (or) supply voltage, VL- load voltage and VO- sag voltage. The phase angle of the supply voltage may be shifted by injecting DVR series voltage to the system.

DVR S

L

V V

V  

………. (3)

In this method the real power spent by the UPQC is decreased by minimizing the power angle between the sag voltage and load current. In case of pre-sag and in-phase compensation method the active power is injected into the system during disturbances. The active power supply is limited, so energy is stored energy in the DC links, This part is one of the most expensive parts of UPQC. The minimization of injected energy is achieved by making the active power component zero by having the injection voltage phasor perpendicular to the load current phasor.

4.1. POSTCAST CONTROLLER AND P + RESONANT CONTROLLER

Fig.7. Open-loop control using postcast controller The Explain controller is used in order to improve the transient response of the UPQC. Multiple feeders connected to a common bus, namely “the Point of Common Coupling (PCC)”. A simple method to continue is to feed the error signal into the PWM inverter of the UPQC. But the transient oscillations initiated at the start instant from the voltage sag could not be damped out sufficiently. To improve the damping, the Postcast controller can be used just before transferring the signal to the PWM inverter of the UPQC. The transfer function of the controller can be described as follows:

………. (4) Where δ and Td are the step response overshoot and the period of damped response signal, respectively.

UPQC harmonic filter has an inductance

L

_f , a resistance

R

_f and capacitance of

C

_f and the UPQC injection transform has a combined winding resistance of Rt, a leakage inductance of Lt and turns ratio of 1:n. According to the equation (2), the δ and Td are

……….. (5) Post cast controller is sensitive to inaccurate information of the system damping resonance frequency. To decrease this sensitivity, the open-loop controller can be converted to a closed loop controller by adding a multi loop feedback path parallel to the existing feed forward path. The feedback path consists of an outer voltage loop and a fast inner current loop.

(6)

_____________________________________________________________________________________________

Fig.8. Multiloop control using Posicast and P+Resonant controllers

To eliminate the steady-state voltage tracking error (

)

( V

_L^*

 V

_L , a computationally less intensive P+Resonant compensator is added to the outer voltage loop. The ideal P+Resonant compensator can be mathematically expressed as

………….. (6)

Where and are kp and kI are gain constants and

sec / 50

2 rad

o

  



is the controller resonant

frequency. Theoretically, the resonant controller compensates by introducing an infinite gain at the resonant frequency of 50 Hz, to force the steady-state voltage error to zero. A more practical a nonideal compensator is used here, and is expressed as

………… (7) Where,



_cutis the compensator cut off frequency for this UPQC application

1rad / sec

.Fig. 8.shows the Plot of the frequency response of equation (7) for non-ideal P+Resonant controller, that the resonant peak with a finite gain of 40 dB which is satisfactorily high for eliminating the voltage tracking error. Wider bandwidth around the resonant frequency, which minimizes the sensitivity of the compensator to slight utility frequency variations.

Fig.9. Typical response of the non-ideal P+Resonant controller

4.2. PROPOSED METHOD FOR FLUX –CHARGED MODEL BASED UPQC

The proposed algorithm for the UPQC is used to restore the PCC voltage, limit the fault current, and, therefore, protect the UPQC components. In the flux-charge model, the UPQC acts as a virtual inductance with a variable value in series with the distribution feeder, by injecting a proper voltage having the opposite polarity with respect to usual cases.

Fig.10. Proposed method using P+ Resonator (flux regulator) with charge regulator

The proposed UPQC limit the downstream fault current and this current will restore the point of common coupling (PCC) (the bus to which all feeders under study are connected) voltage and protect the UPQC itself. It is necessary to operate the over current circuit breaker (CB) at PCC.The communication between the UPQC and the PCC breaker can be done by sending a signal to the breaker when the UPQC is in the fault-current limiting mode as the UPQC is just located after PCC.

The reference flux

  

ref is derived by integration of the subtraction of the PCC reference voltage and the UPQC load-side voltage. The inverter-filtered terminal flux is used for the outer flux model as a control variable and defined as



 

_FDVR

dt



……. (8)

Where



_FDVRis the UPQC filter capacitor voltage at the UPQC power converter side of the injection transformer. The flux error is then send to the P+

Resonant controller based flux regulator. A single flux-model would not damp out the resonant peak of the LC filter connected to the output of the inverter.

The filter inductor charge based inner charge model is considered, to stabilize the system , which is derived by integration of its current, tracks the reference charge Q ref output of the flux regulator.

The calculated charge error isthen applied to the charge regulator with the transfer function as follows:

(7)

_____________________________________________________________________________________________

…… (9) The expression(9) is fora actually a practical form of the derivative controller and this transfer function, the regulator gain N is limited to at high frequencies to prevent noise amplification. The derivative term in

S N S

 1

neutralizes the effects of voltage and current integrations at the inputs of the flux-charge model, resulting in the proposed algorithm having the same regulation performance as the multiloop voltage-current feedback control, with the only difference being the presence of an additional low–

pass filter in the flux control loop in the form of

S N

 1

1

. The bandwidth of this low–pass filter is

tuned (through varying N) with consideration for measurement noise attenuation, UPQC LC-filter transient resonance attenuation, and system stability margins.

5. SIMULATION RESULT

The simulation result of the multifunctional UPQC in the distributed system is shown in the Figure 8.14 using MATLAB software. The start of a three phase large induction motor is considered as the case of fault conditions. To the UPQC system, a sudden load of 10MW was applied to test the system within the time period from t = 0.3 sec to t = 0.6 seconds by using the breaker operation. This causes a voltage sag in the system which also affects the critical load. At this instant the UPQC starts compensating for the voltage drop and restores both the critical load voltage as well as the source voltage.

Fig. 11 Simulation Diagram

LOAD VOLTAGE

When the proposed system is activated the sag occurred can be cleared . The fig.12 shows the stable condition of response.

LOAD CURRENT

REAL POWER AND REACTIVE POWER

CONTROLLER

GATE PULSE

(8)

_____________________________________________________________________________________________

RMS SAG MAGNITUDE

CONCLUSION

This paper presents the study and the experimental validation of a local three-phase,four-wire power distribution system. The system, indicated for applications in rural or remote areas where three- phase distribution grids are not accessible, was conceived based on unified power quality conditioner

functionalities. With serial and parallel filtering capability, two inverter topologies were used to design compose the UPQC-1Ph-to-3Ph. Thereby, the single-phase series converter was deployed using a half-bridge inverter,while the three-phase parallel converter was implemented using a 3-Leg split capacitor inverter.

Using the dual compensation strategy, the proposed system was able of feeding linear and non-linear three-phase loads acting with universal active filtering capability, i.e., acting as SAPF and PAPF. In addition, a procedure was presented that allows the dimensioning of the power structures of the series and parallel converters, under various operating conditions of the utility grid and the load. The static and dynamic behavior of the UPQC-1Ph-to-3Ph has been proved to be satisfactory through extensive experimental results.

REFERENCES

[1] N. Hosseinzadeh, and J. Rattray, “Economics of upgrading SWER distribution systems”, in Proc.

Australasian Universities Power Engineering Conference (AUPEC), 2008, pp. 1–7.

[2] F. Rosa, and S. T. Mak, “A look into steady state and transient performance of power lines integrating single wire earth return circuits” in Proc. IEEE Power Engineering Society General Meeting, 2007, pp. 1–7.

[3] A. Guinane, G. M. Shafiullah, A. M. T. Oo, and B. E. Harvey “Voltage fluctuations in PV penetration on SWER networks - A Case Study for Regional Australia”, in Proc. IEEE Power and Energy Society General Meeting, 2012, pp. 1–6.

[4] P. J. Wolf, “Capacity improvements for rural single wire earth return systems” in Proc. 7th International Power Engineering Conference (IPEC), 2005, pp. 1–8.

[5] S. N. Lowry, A. M. T. Oo, and G. Robinson,

“Deployment of low voltage switched capacitors on single wire earth return networks” in Proc. 22nd Australasian Universities Power Engineering Conference (AUPEC), 2012, pp. 1–5,

[6] M. D. Bellar, M. Aredes, J. L. Silva Neto, L. G.

B. Rolim, F. C. Aquino, and V. C. Petersen, “Single- phase static converters for rural distribution system”, in Proc. IEEE International Symposium on Industrial Electronics (ISIE), 2004, pp.1237–1242.

(9)

_____________________________________________________________________________________________

[7] R. Z. Scapini, C. Rech, T. B. Marchesan, L.

Schuch, R. F. Camargo, and L. Michels,

“Distribution STATCOM integrated to a single-phase to three-phase converter” in Proc. 40th Annual Conference of IEEE Industrial Electronics Society (IECON), 2014, pp.1423–1429.

[8] A. Helwig, and T. Ahfock, “Long-life nickel iron battery functionality/cost comparison for peak demand SWER network voltage support application”

in Proc. 23th Australasian Universities Power Engineering Conference (AUPEC), 2013, pp. 1–6.

[9] E. C. Santos Jr, N. Rocha, and C. B. Jacobina,

“Suitable single-phase to three-phase AC-DC-AC power conversion system”, IEEE Trans. on Power Electron., vol. 32, no. 7, pp. 860–870, Feb. 2015.

[10] N. Rocha, I. A. C. Oliveira, E. C. Menezes, C.

B. Jacobina, and J. A. A. Dias, “Single-phase to three-phase converters with two parallel single-phase rectifiers and reduced switch count”, IEEE Trans. on Power Electron., vol. 31, no. 5, pp. 3701–3716, May 2016.

[11] V. Verma, and A. Kumar “Cascaded multilevel active rectifier fed three-phase smart pump load on single-phase rural feeder”, IEEE Trans. on Power Electron., vol. 30, no. 2, pp. 5398–5410, Jul. 2017.

[12] E. C. Santos Jr, C. B. Jacobina, J. A. A. Dias, and N. Rocha, “Single-phase to three-phase universal active power filter”, IEEE Trans. on Power Delivery, vol. 26, no. 3, pp. 1361–1371, Jul. 2011.

[13] F. A. Negrão, S. A. O. Silva, and R. A. Modesto,

“A Single-Phase to Three-Phase UPQC Topology with Universal Filtering Capabilities,” in Proc. of 13th Brazilian Power Electronics Conference and 1st IEEE Southern Power Electronics Conference, pp. 1- 6, 2015.

[14] Y. Lu, G. Xiao, X. Wang, F. Blaabjerg, and D.

Lu, “Control strategy for single-phase transformerless three-leg unified power quality conditioner based on space vector modulation,” IEEE Trans. on Power Electron., vol. 31, no. 4, pp. 2840–

2849, Ap. 2016.

[15] A. M. Rauf, A. V. Sant, V. Khadkikar, and H. H.

Zeineldin “A Novel Ten-Switch Topology for Unified Power Quality Conditioner,” IEEE Trans.

Power Electron., vol. 31, no. 10, pp. 6937-6946, Oct.

2016.

[16] L. B. G. Campanhol, S. A. O. Silva, A. A., Oliveira Jr., and V. D. Bacon, “Single-Stage Three- Phase Grid-Tied PV System with Universal Filtering Capability Applied to DG Systems and AC Microgrids,” IEEE Trans. on Power Electron., Early Access, Jan. 2017.

[17] R. J. M. Santos, J. C. Cunha, and M. Mezaroba,

“A simplified control technique for a dual unified power quality conditioner”, IEEE Trans. on Ind.

Electron., vol. 61, no. 11, pp. 5851–5860, Nov. 2014.

[18] B. W. França, L. F. Silva, M. A. Aredes, and M.

Aredes, “An improved iUPQC controller to provide additional grid-voltage regulation as a STATCOM,”

IEEE Trans. on Ind. Electron., vol. 62, no. 3, pp.

1345–1352, Mar. 2015.

[19] R. A. Modesto, S. A. O. Silva, A. A., Oliveira Jr., and V. D. Bacon, “Versatile unified power quality conditioner applied to three-phase four-wire distribution systems using a dual control strategy,”

IEEE Trans. on Power Electron., vol. 31, no. 8, pp.

5503–5514, Aug. 2016.

[20] V. D. Bacon, S. A. O. Silva, L. B. G.

Campanhol, and B. A. Angélico, “Stability analysis and performance evaluation of a single-phase phase- locked loop algorithm using a non-autonomous adaptive filter”, IET Power Electron., vol. 7, no. 8, pp. 2081–2092, Aug. 2014.

[21] S. A. O. Silva, R. A. Modesto, “A comparative analysis of SRF-based controllers applied to active power line conditioners” in Proc. 34th Annual Conference of IEEE Industrial Electronics Society (IECON), 2008, pp.405–410.

[22] B. A. Angélico, L. B. G. Campanhol, and S. A.

O. Silva, “Proportional–integral/proportional–

integral–derivative tuning procedure of a single- phase shunt active power filter using bode diagram,”

IET Power Electron., vol. 7, no. 10, pp. 2647–2659, Aug. 2014.

[23] IEEE Standard Definitions for the Measurement of Electric Power Quantities under Sinusoidal, Nonsinusoidal, Balanced, or Unbalanced Conditions, IEEE Std. 1469-2010, 2010, New York, USA.

[24] K. Karanki, G. Geddada, M. K. Mishra, and B.

K. Kumar, “A modified three-phase four-wire UPQC topology with reduced dc-link voltage rating,” IEEE Trans. On Ind. Electron., vol. 60, no. 9, pp. 3555- 3566, Sept. 2013.

(10)

_____________________________________________________________________________________________

[25] S. Buso, and P. Mattavelli, Digital Control in Power Electronics. Lincoln, NE, USA: Morgan &

Claypool, 2006.

About Authors

Vivek Kumar is an assista nt profess or at IFTM University, Moradabad in Electrical Engineering Department.

Currently he is pursuing his Ph.D. from the same university and earned an M.Tech degree in Power System from SRM University, Tamilnadu,

Profe ssor GK Bane rjee was born in Raip ur in 1947. He received his B.Sc. Engg.

(Electrical) degree in

1968 from AMU

Aligarh, M.Sc. Engg.

(Electrical) in 1983 from AMU, Aligrah and Ph.D

India. Earlier he worked as an Assistant Professor at NarainaVidyapeeth, Kanpur and ACT College

of Engineering,

Kanchipuram, India. His areas of interest include Voltage stability, Optimization Techniques and Power System Control.

in electrical engineering from G.B. Pant

University of

Agriculture &

Technology Pantnagar in 1998. He was at Pantnagar during 1984- 2011 and retired from Pantnagar as Professor.

After retiring from Pantnagar he joined IFTM University, Moradabad.He has published two books and 13 papers and edited three Laboratory manuals. His areas of interest include electrical machines &

instrumentation engineering.