EPE Association: EPE 2003 - Topic 12e: Power Conditioning, Power Factor Correction

EPE 2003 - Topic 12e: Power Conditioning, Power Factor Correction
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 12: POWER ELECTRONICS IN GENERATION, TRANSMISSION AND DISTRIBUTION OF ELECTRICAL ENERGY > EPE 2003 - Topic 12e: Power Conditioning, Power Factor Correction

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   Phase-Locked Loop for Static Series Compensator
By H. Awad; J. Svensson; M. Bollen [View]
[Download]

Abstract: Accurate phase information is crucial for most of the modern power electronics apparatus such as the static series compensator. A software phase-locked loop (SPLL) has been proposed in literature to obtain phase and frequency information of the grid voltage. Either a lead/lag filter or a PI-controller is employed to control the performance of the SPLL. However, it has not been declared how to tune the SPLL for SSC applications. In this paper, a criterion to tune the SPLL for SSC applications is discussed and the gains of the PI-controller are determined to obtain the desired performance. The proposed criterion is based on the fact that a phase angle jump of the grid voltage is sensed as a frequency deviation by the load, and owing to European standard, most of the loads should function properly if the deviation of the grid frequency is kept within ± 1Hz. Unbalanced grid voltages are separated into positive and negative sequences and the SPLL is locked to the positive sequence. The response of the SPLL has been evaluated by applying phase step of the actual grid phase. Also, the SSC together with the SPLL have been modeled and simulated using PSCAD/EMTDC package. Simulation results in case of a voltage dip associated with a phase jump is presented.

   Implementation of a PIS compensator for three phase utility interface converters
By S. Fukuda; R. Imamura [View]
[Download]

Abstract: Three phase voltage-source converters are used as a utility interface. In such a case, the converter line currents are required to track sinusoidal references synchronized with the utility grid without a steady-state error. In this paper a current control method based on a sinusoidal internal model is employed. The method uses a sine transfer function with a specified resonant frequency, which is called an S-compensator. The combination of a conventional PI compensator and an S-compensator is called a PIS compensator. The PIS compensator ensures that the steady-state error in response to any step changes in a reference signal at the resonant frequency and zero hertz reduces to zero. Experiment was carried out using a 1kVA prototype of three utility-interface-converters, a voltage source rectifier, an active power filter, and STATCOM. Almost perfect current tracking performance can be observed.

   Power factor correction of high power winding rotor induction motor based on single phase to three phases cycloconverter
By D. Chaoping; L. Zhinbin; Y. Pengsheng [View]
[Download]

Abstract: A way of power factor correction of high power winding rotor induction motor is proposed. By using a voltage source with series connection to the rotor of induction motor, the unity power factor can be obtained. The amplitude and phase of the voltage source are variable and its frequency follows the rotor current frequency. A single phase to three phases cycloconverter to realize this voltage source is designed. This cycloconverter uses 12 thyristors and the control strategy is much simple than the traditional converter. Moreover, the control strategy ensures the soft-switching for thyristors. PSPICE simulation is performed to confirm the correction operation of control strategy. A prototype of a 400kW induction motor was developed, the results confirm the validity of the analysis. The power factor of induction motor reaches 0.97 and the system is robust to the variable load.

   The research of a new kind of continuous reactive power compensator
By L. Zhibin; D. Chaoping; Y. Pengshen [View]
[Download]

Abstract: this paper, a new kind of continuous reactive power compensator - capacitor link compensator (CLC) is proposed. The principles of continuous reactive and harmonic compensation are described. The experimental data have proved the analysis. The CLC is compared with ASVG, and the situations which CLC suits is point out.

   DTC-based power conditioning system capable of grid-connected and grid-independant operation
By A. Tarkiainen; R. Pöllänen; M. Niemelä; J. Pyrhönen [View]
[Download]

Abstract: The paper introduces the use of the DTC modulation technology to a power conditioning system. The system may be operated either in grid-connected or in grid-independent mode. The mode change does not introduce any degradation in the power quality. Practical measurements with a 19 kVA industrial converter demonstrate the good performance of the proposed system.

   Control algorithms for compensation with active power line conditioners
By P. Salmerón; J. C. Montaño; J. R. Vázquez; J. Prieto; A. Pérez [View]
[Download]

Abstract: In three-phase four-wire systems, two compensation criteria are possible. One exclusive of the threephase circuits, is based on the instantaneous value concept. It consist in eliminating the non instantaneous power current without altering the instantaneous real power. Another, is based on the average value concept and the non-active average-current is reduced, without altering the average power. When the zero-sequence voltage component exists, both compensation criteria would not enable the zero-sequence (neutral) source current elimination. Then, two approaches are marked in this paper. The first one is for eliminating the non instantaneous power current or the non-active average-current but the neutral current can still flow. The second one for eliminating the modified non instantaneous power current or the modified non-active average-current, thus the neutral current component is compensated. According to recent recommendations in this work three-phase systems are considered as four-conductor systems. Finally, experimental results to prove the compensation strategies are obtained.

   A new dynamic voltage restorer for use in the weak distribution systems
By Y. Cheng; P. Lataire [View]
[Download]

Abstract: A Dynamic Voltage Restorer (DVR) is proposed for use in highly resistive distribution lines to boost excessive voltage drops. Then higher power transfers are allowed and high power quality is achieved. The selection of controlled variables and the control loops are discussed, besides the hardware and experimental results.

   Application of the instantaneous power theories in load compensation with active power filters
By P. Salmerón Revuelta; M. Reyes Sánchez Herrera [View]
[Download]

Abstract: Today, the main theory for the design of APF (Active Power Filter) control for non-linear three-phase loads compensation has been the instantaneous reactive power theory. Since 1983 when p-q original theory appeared, there have been proposed many different formulations applied to the APF control. However, the compensation strategies derived from the different instantaneous reactive power formulations present a different behaviour when unbalanced and non-sinusoidal source voltages are applied to three-phase four-wire systems. In this paper, the behaviour of different APF control algorithms got from the five most relevant instantaneous reactive power formulations, according to the outstanding publication, is analysed. They are p-q original, d-q transformation, modified or cross product formulation, p-q-r reference frame and vectorial formulation. A platform of simulation with control + APF + load to test the different algorithms has been built. The results got in the following three cases were compared: balanced and sinusoidal, unbalanced and sinusoidal, and balanced and non sinusoidal source voltage. The analysis of results from the five formulations proved that only the vectorial one allows to get balanced and sinusoidal currents after compensation.

   The practical approach of employing the series power conditioner for power quality improvement in distribution systems
By A. Elnady; M. M. A. Salama [View]
[Download]

Abstract: This paper presents novel functionalities of the Dynamic Voltage Restorer (DVR). A DVR is commonly used to mitigate the voltage sags. In this paper the proposed DVR can compensate the voltage unbalance and mitigate voltage harmonics in the time of normal operation in addition to its basic functions in the fault time. The suggested algorithm employs an adaptive perceptron to effectively and adaptively track and extract the most common voltage harmonics, voltage unbalance (which include negative and zero sequence voltage drops), and different types of voltage sags, (which include balanced and unbalanced voltage sags). Digital simulation results are obtained using PSCAD/EMTDC to verify the effectiveness of the proposed algorithm. Experimental results are also demonstrated to validate the practicality of the new functionalities for the DVR.

   Residual current compensators (RCC) for resonant grounded transmission systems using high performance voltage source inverters (VSI)
By M. Janssen; S. Kraemer; R. Schmidt; K. Winter [View]
[Download]

Abstract: A novel FACTS equipment, the Residual Current Compensation (RCC), overcomes the restrctions of resonant grounding completely and makes the method of Peterson perfect: a Voltage Source Inverter (VSI) in the neutral system generates the voltage required to activily compensate the residual current whilst continuying the power supply. A Residual Current Compensation was installed in an 110-kV-grid, involving 18500 km of lines. The RCC consists of a 5.5 MVA 3-level-VSI using Gate Turn Off Thyristors (GTO). The paper describes the design criteria with respect to the relevant grid parameters and the closed loop control based upon the admittance of the neutral system. The effectiveness is proven by carried out field tests. The perfect earth fault management for both extended overhead lines and cables may create reviewed guidelines of planning resonant grounded 110-kV-grids with higher availability and power quality.

   Mains active restoring systems. Industrial Applications.
By S. Kalaschnikow [View]
[Download]

Abstract: In industrial low and medium voltage mains, passive filters and PFC capacitors have traditionally been used to improve the supply quality. However, they cannot be rated only for the loads being compensated. They are affected by harmonic currents from other non-linear loads or by harmonics from the power system. Compared with passive element compensators, the Mains Active Restoring System (MARS) can be used to improve the supply quality without worrying about all the problems associated with applying passive elements.

   Integration of static VAR compensation systems by utilizing Power Transformer Tertiary windings
By S. E. E. Abo Shady; A. A. Mahfouz; Y. A. Nasef [View]
[Download]

Abstract: A novel scheme of static var shunt compensators (SVC) is introduced that integrates the compensator with commonly used transmission equipment like power transformer. Adopting such technique yields to remarkable enhancement of the transformer efficiency and voltage regulation. Also the transformer winding's leakage inductance employed as a harmonic filter that minimizes the cost and rooming of such filter. The SVC will be considered as a variable capacitor through modulating 3 phase PWM inverter. System is analyzed at different modes of operation to develop control algorithm. Experimental as well as computer simulation cases have been investigated to verify the system operation.

   A new method for real time active filtering of power line distortions through wavelet transform
By A. Centonza; M. K. Darwish [View]
[Download]

Abstract: An innovative method using active filters for real time compensation of power line current distortions up to 5KHz is presented. The method is based on the Wavelet Transform (WT), which offers more accurate time frequency resolution in comparison with Fast Fourier Transform (FFT). The WT also provides the flexibility of handling either periodic or non-periodic signals, yielding to the detection in the time domain of all kinds of disturbances within a certain frequency range.

EPE 2003 - Topic 12e: Power Conditioning, Power Factor Correction
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 12: POWER ELECTRONICS IN GENERATION, TRANSMISSION AND DISTRIBUTION OF ELECTRICAL ENERGY > EPE 2003 - Topic 12e: Power Conditioning, Power Factor Correction
	[return to parent folder]

	Phase-Locked Loop for Static Series Compensator By H. Awad; J. Svensson; M. Bollen	[View] [Download]
Abstract: Accurate phase information is crucial for most of the modern power electronics apparatus such as the static series compensator. A software phase-locked loop (SPLL) has been proposed in literature to obtain phase and frequency information of the grid voltage. Either a lead/lag filter or a PI-controller is employed to control the performance of the SPLL. However, it has not been declared how to tune the SPLL for SSC applications. In this paper, a criterion to tune the SPLL for SSC applications is discussed and the gains of the PI-controller are determined to obtain the desired performance. The proposed criterion is based on the fact that a phase angle jump of the grid voltage is sensed as a frequency deviation by the load, and owing to European standard, most of the loads should function properly if the deviation of the grid frequency is kept within ± 1Hz. Unbalanced grid voltages are separated into positive and negative sequences and the SPLL is locked to the positive sequence. The response of the SPLL has been evaluated by applying phase step of the actual grid phase. Also, the SSC together with the SPLL have been modeled and simulated using PSCAD/EMTDC package. Simulation results in case of a voltage dip associated with a phase jump is presented.

	Implementation of a PIS compensator for three phase utility interface converters By S. Fukuda; R. Imamura	[View] [Download]
Abstract: Three phase voltage-source converters are used as a utility interface. In such a case, the converter line currents are required to track sinusoidal references synchronized with the utility grid without a steady-state error. In this paper a current control method based on a sinusoidal internal model is employed. The method uses a sine transfer function with a specified resonant frequency, which is called an S-compensator. The combination of a conventional PI compensator and an S-compensator is called a PIS compensator. The PIS compensator ensures that the steady-state error in response to any step changes in a reference signal at the resonant frequency and zero hertz reduces to zero. Experiment was carried out using a 1kVA prototype of three utility-interface-converters, a voltage source rectifier, an active power filter, and STATCOM. Almost perfect current tracking performance can be observed.

	Power factor correction of high power winding rotor induction motor based on single phase to three phases cycloconverter By D. Chaoping; L. Zhinbin; Y. Pengsheng	[View] [Download]
Abstract: A way of power factor correction of high power winding rotor induction motor is proposed. By using a voltage source with series connection to the rotor of induction motor, the unity power factor can be obtained. The amplitude and phase of the voltage source are variable and its frequency follows the rotor current frequency. A single phase to three phases cycloconverter to realize this voltage source is designed. This cycloconverter uses 12 thyristors and the control strategy is much simple than the traditional converter. Moreover, the control strategy ensures the soft-switching for thyristors. PSPICE simulation is performed to confirm the correction operation of control strategy. A prototype of a 400kW induction motor was developed, the results confirm the validity of the analysis. The power factor of induction motor reaches 0.97 and the system is robust to the variable load.

	The research of a new kind of continuous reactive power compensator By L. Zhibin; D. Chaoping; Y. Pengshen	[View] [Download]
Abstract: this paper, a new kind of continuous reactive power compensator - capacitor link compensator (CLC) is proposed. The principles of continuous reactive and harmonic compensation are described. The experimental data have proved the analysis. The CLC is compared with ASVG, and the situations which CLC suits is point out.

	DTC-based power conditioning system capable of grid-connected and grid-independant operation By A. Tarkiainen; R. Pöllänen; M. Niemelä; J. Pyrhönen	[View] [Download]
Abstract: The paper introduces the use of the DTC modulation technology to a power conditioning system. The system may be operated either in grid-connected or in grid-independent mode. The mode change does not introduce any degradation in the power quality. Practical measurements with a 19 kVA industrial converter demonstrate the good performance of the proposed system.

	Control algorithms for compensation with active power line conditioners By P. Salmerón; J. C. Montaño; J. R. Vázquez; J. Prieto; A. Pérez	[View] [Download]
Abstract: In three-phase four-wire systems, two compensation criteria are possible. One exclusive of the threephase circuits, is based on the instantaneous value concept. It consist in eliminating the non instantaneous power current without altering the instantaneous real power. Another, is based on the average value concept and the non-active average-current is reduced, without altering the average power. When the zero-sequence voltage component exists, both compensation criteria would not enable the zero-sequence (neutral) source current elimination. Then, two approaches are marked in this paper. The first one is for eliminating the non instantaneous power current or the non-active average-current but the neutral current can still flow. The second one for eliminating the modified non instantaneous power current or the modified non-active average-current, thus the neutral current component is compensated. According to recent recommendations in this work three-phase systems are considered as four-conductor systems. Finally, experimental results to prove the compensation strategies are obtained.

	A new dynamic voltage restorer for use in the weak distribution systems By Y. Cheng; P. Lataire	[View] [Download]
Abstract: A Dynamic Voltage Restorer (DVR) is proposed for use in highly resistive distribution lines to boost excessive voltage drops. Then higher power transfers are allowed and high power quality is achieved. The selection of controlled variables and the control loops are discussed, besides the hardware and experimental results.

	Application of the instantaneous power theories in load compensation with active power filters By P. Salmerón Revuelta; M. Reyes Sánchez Herrera	[View] [Download]
Abstract: Today, the main theory for the design of APF (Active Power Filter) control for non-linear three-phase loads compensation has been the instantaneous reactive power theory. Since 1983 when p-q original theory appeared, there have been proposed many different formulations applied to the APF control. However, the compensation strategies derived from the different instantaneous reactive power formulations present a different behaviour when unbalanced and non-sinusoidal source voltages are applied to three-phase four-wire systems. In this paper, the behaviour of different APF control algorithms got from the five most relevant instantaneous reactive power formulations, according to the outstanding publication, is analysed. They are p-q original, d-q transformation, modified or cross product formulation, p-q-r reference frame and vectorial formulation. A platform of simulation with control + APF + load to test the different algorithms has been built. The results got in the following three cases were compared: balanced and sinusoidal, unbalanced and sinusoidal, and balanced and non sinusoidal source voltage. The analysis of results from the five formulations proved that only the vectorial one allows to get balanced and sinusoidal currents after compensation.

	The practical approach of employing the series power conditioner for power quality improvement in distribution systems By A. Elnady; M. M. A. Salama	[View] [Download]
Abstract: This paper presents novel functionalities of the Dynamic Voltage Restorer (DVR). A DVR is commonly used to mitigate the voltage sags. In this paper the proposed DVR can compensate the voltage unbalance and mitigate voltage harmonics in the time of normal operation in addition to its basic functions in the fault time. The suggested algorithm employs an adaptive perceptron to effectively and adaptively track and extract the most common voltage harmonics, voltage unbalance (which include negative and zero sequence voltage drops), and different types of voltage sags, (which include balanced and unbalanced voltage sags). Digital simulation results are obtained using PSCAD/EMTDC to verify the effectiveness of the proposed algorithm. Experimental results are also demonstrated to validate the practicality of the new functionalities for the DVR.

	Residual current compensators (RCC) for resonant grounded transmission systems using high performance voltage source inverters (VSI) By M. Janssen; S. Kraemer; R. Schmidt; K. Winter	[View] [Download]
Abstract: A novel FACTS equipment, the Residual Current Compensation (RCC), overcomes the restrctions of resonant grounding completely and makes the method of Peterson perfect: a Voltage Source Inverter (VSI) in the neutral system generates the voltage required to activily compensate the residual current whilst continuying the power supply. A Residual Current Compensation was installed in an 110-kV-grid, involving 18500 km of lines. The RCC consists of a 5.5 MVA 3-level-VSI using Gate Turn Off Thyristors (GTO). The paper describes the design criteria with respect to the relevant grid parameters and the closed loop control based upon the admittance of the neutral system. The effectiveness is proven by carried out field tests. The perfect earth fault management for both extended overhead lines and cables may create reviewed guidelines of planning resonant grounded 110-kV-grids with higher availability and power quality.

	Mains active restoring systems. Industrial Applications. By S. Kalaschnikow	[View] [Download]
Abstract: In industrial low and medium voltage mains, passive filters and PFC capacitors have traditionally been used to improve the supply quality. However, they cannot be rated only for the loads being compensated. They are affected by harmonic currents from other non-linear loads or by harmonics from the power system. Compared with passive element compensators, the Mains Active Restoring System (MARS) can be used to improve the supply quality without worrying about all the problems associated with applying passive elements.

	Integration of static VAR compensation systems by utilizing Power Transformer Tertiary windings By S. E. E. Abo Shady; A. A. Mahfouz; Y. A. Nasef	[View] [Download]
Abstract: A novel scheme of static var shunt compensators (SVC) is introduced that integrates the compensator with commonly used transmission equipment like power transformer. Adopting such technique yields to remarkable enhancement of the transformer efficiency and voltage regulation. Also the transformer winding's leakage inductance employed as a harmonic filter that minimizes the cost and rooming of such filter. The SVC will be considered as a variable capacitor through modulating 3 phase PWM inverter. System is analyzed at different modes of operation to develop control algorithm. Experimental as well as computer simulation cases have been investigated to verify the system operation.

	A new method for real time active filtering of power line distortions through wavelet transform By A. Centonza; M. K. Darwish	[View] [Download]
Abstract: An innovative method using active filters for real time compensation of power line current distortions up to 5KHz is presented. The method is based on the Wavelet Transform (WT), which offers more accurate time frequency resolution in comparison with Fast Fourier Transform (FFT). The WT also provides the flexibility of handling either periodic or non-periodic signals, yielding to the detection in the time domain of all kinds of disturbances within a certain frequency range.