A conventional steady-state power flow security check only implements point-by-point assessment, ... more A conventional steady-state power flow security check only implements point-by-point assessment, which cannot provide a security margin for system operation. The concept of a steady-state security region is proposed to effectively tackle this problem. Considering that the commissioning of the increasing number of HVDC (High Voltage Direct Current) and the fluctuation of renewable energy have significantly affected the operation and control of a conventional AC system, the definition of the steady-state security region of the AC/DC power system is proposed in this paper based on the AC/DC power flow calculation model including LCC/VSC (Line Commutated Converter/Voltage Sourced Converter)-HVDC transmission and various AC/DC constraints, and hence the application of the security region is extended. In order to ensure that the proposed security region can accurately provide global security information of the power system under the fluctuations of renewable energy, this paper presents four methods (i.e., a screening method of effective boundary surfaces, a fitting method of boundary surfaces, a safety judging method, and a calculation method of distances and corrected distance between the steady-state operating point and the effective boundary surfaces) based on the relation analysis between the steady-state security region geometry and constraints. Also, the physical meaning and probability analysis of the corrected distance are presented. Finally, a case study is demonstrated to test the feasibility of the proposed methods.
It is vital to improve the stability of the power system by accurately identifying the modal para... more It is vital to improve the stability of the power system by accurately identifying the modal parameters of damped low-frequency oscillations (DLFO) and controlling the oscillation in time. A new method based on empirical mode decomposition (EMD), stochastic subspace identification (SSI), and Prony algorithms, called synthetical modal parameters identification (SMPI) method, is developed by efficiently matching the modal parameters of DLFO which are acquired from the SSI and Prony algorithm. In this approach, EMD is used for denoising the raw oscillation signals thereby enhancing the noise resistance, and then using the SSI and Prony algorithms to identify the precise modal parameters assisted by parameter matching. It is demonstrated that the proposed SMPI method holds great accuracy in identifying full modal parameters including natural frequencies, damping ratios, amplitudes, and phase angles with simulated signals with known modal parameters and real-time signals from some power ...
In view of modern power system characterized by significant inertia reduction and booming uncerta... more In view of modern power system characterized by significant inertia reduction and booming uncertainty, this letter proposes an important operational planning tool to comprehensively analyze frequency stability including both steady-state frequency and rate of change of frequency (RoCoF) issues in a probabilistic manner for the first time. The proposed generic framework can tackle various frequency-related uncertainties and accommodate different system frequency response (SFR) models. The effectiveness and efficiency of the proposed analytical probabilistic assessment are demonstrated by comparing with numerical scenario-based simulation (SBS). Index Terms-Cumulant-based theory, frequency nadir/vertex (FN/FV), rate of change of frequency (RoCoF), renewable energy.
A conventional steady-state power flow security check only implements point-by-point assessment, ... more A conventional steady-state power flow security check only implements point-by-point assessment, which cannot provide a security margin for system operation. The concept of a steady-state security region is proposed to effectively tackle this problem. Considering that the commissioning of the increasing number of HVDC (High Voltage Direct Current) and the fluctuation of renewable energy have significantly affected the operation and control of a conventional AC system, the definition of the steady-state security region of the AC/DC power system is proposed in this paper based on the AC/DC power flow calculation model including LCC/VSC (Line Commutated Converter/Voltage Sourced Converter)-HVDC transmission and various AC/DC constraints, and hence the application of the security region is extended. In order to ensure that the proposed security region can accurately provide global security information of the power system under the fluctuations of renewable energy, this paper presents four methods (i.e., a screening method of effective boundary surfaces, a fitting method of boundary surfaces, a safety judging method, and a calculation method of distances and corrected distance between the steady-state operating point and the effective boundary surfaces) based on the relation analysis between the steady-state security region geometry and constraints. Also, the physical meaning and probability analysis of the corrected distance are presented. Finally, a case study is demonstrated to test the feasibility of the proposed methods.
This paper proposes a method of probabilistic analysis to investigate the impact of stochastic un... more This paper proposes a method of probabilistic analysis to investigate the impact of stochastic uncertainty of grid-connected wind generation on power system small-signal stability. The proposed method is "analytical" in contrast to the numerical method of Monte Carlo simulation which relies on large number of random computations. It can directly calculate the probabilistic density function (PDF) of critical eigenvalues of a large-scale power system from the PDF of grid-connected multiple sources of wind power generation, thus to determine the probabilistic small-signal stability of the power system as affected by the wind generation. In the paper, an example of 16-machine power system with 3 grid-connected wind farms is used to demonstrate the application of the proposed method. The results of probabilistic stability analysis of the example power system are confirmed by the Monte Carlo simulation. It is shown that the stochastic variation of grid-connected wind generation can cause the system to lose stability even though the system is stable deterministically. The higher the level of wind penetration is, the more the probability that the system becomes unstable could be. Hence indeed penetration of stochastically variable wind generation threats stable operation of power systems as far as system small-signal stability is concerned.
In order to improve the small-signal stability of AC/DC hybrid systems containing voltagesource c... more In order to improve the small-signal stability of AC/DC hybrid systems containing voltagesource converter based high-voltage direct current (VSC-HVDC), this article extends damping torque analysis (DTA) theory to VSC-HVDC supplementary damping controller to analyze its dynamic impacts and inhibit oscillations. Firstly, this article presents the mechanism and procedure of VSC supplementary damping controller and establishes the linearized model of AC/DC system with damping controllers. On this basis, the DTA theory of VSC supplementary damping controller and the equation of damping torque index (DTI) are derived. The theory can be applied to the design of the damping controller including the selection of installation location and channel as well as the parameter tuning. Finally, case studies are carried out in two AC/DC hybrid systems containing VSC-HVDC. The simulation results verify the correctness and feasibility of DTI analysis. VSC damping controllers designed by the proposed method can effectively suppress oscillations and improve the dynamic stability of the AC/DC system. INDEX TERMS VSC-HVDC, supplementary damping controller, damping torque analysis (DTA), smallsignal stability, ac/dc system.
Oscillatory stability has received immense attention in recent years due to the significant incre... more Oscillatory stability has received immense attention in recent years due to the significant increase in power electronic converter (PEC)-interfaced renewable energy sources. Synchrophasor technology offers superior capability to measure and monitor power systems in real time, and power system operators require better understanding of how it can be used to effectively analyze and control oscillations. This article reviews state-of-the-art oscillatory stability monitoring, analysis, and control techniques reported in the published literature based on synchrophasor technology. An updated classification is presented for power system oscillations with a special emphasis on oscillations induced from PEC-interfaced renewable energy generation. Oscillatory stability analysis techniques based on synchrophasor technology are well established in power system engineering, but further research is required to effectively utilize synchrophasor-based oscillatory stability monitoring, analysis, and control techniques to characterize and mitigate PEC-induced oscillations. In particular, emerging big data analytics techniques could be used on synchrophasor data streams to develop oscillatory stability monitoring, analysis, and damping techniques.
This paper presents a novel framework for cooperative trading in a price-maker wind power produce... more This paper presents a novel framework for cooperative trading in a price-maker wind power producer, that participates in the short-term electricity balance markets. In this framework, market price uncertainty is first modeled using a price uncertainty predictor, consisting of ridge regression (RR), nonpooling convolutional neural network (NPCNN), and linear quantile regression (LQR). RR is employed to select the correlated features to the corresponding forecast day, NPCNN is employed to extract the nonlinear features, and LQR is employed to estimate the price uncertainty. Then, an improved firefly algorithm (IFA) is proposed to solve the optimization problem. IFA uses the adaptive moment estimation method to improve the convergence speed and search for the global solution. Finally, the Shapley value is employed for the profit distribution of cooperative power producers. Illustrative examples show the effectiveness of the proposed framework and optimization model
11th IET International Conference on Advances in Power System Control, Operation and Management (APSCOM 2018), 2018
Заведующая клинико-диагностической лабораторией, врач клинической лабораторной диагностики ГБУЗ «... more Заведующая клинико-диагностической лабораторией, врач клинической лабораторной диагностики ГБУЗ «КБСМП г. Краснодара» Улитина Нина Николаевна канд. биол. наук, доцент кафедры биохимии и физиологии Кубанского государственного университета г. Краснодар Кашкова Марина Дмитриевна студентка 1 курса магистратуры Кубанского государственного университета, биологического факультета, кафедры биохимии и физиологии г.
2020 IEEE 4th Conference on Energy Internet and Energy System Integration (EI2), 2020
The emerging information technologies provides an opportunity for supporting the planning of ener... more The emerging information technologies provides an opportunity for supporting the planning of energy industry development. This paper presents an overview on the application of the novel information technologies including big data, artificial intelligence (AI), cloud computing and virtual reality (VR) in the modern energy strategy planning (ESP). Firstly, the concept and current challenges of ESP is briefly reviewed and some typical information technologies which might be suitable for modern ESP are summarized. Secondly, the major technical needs of modern ESP are investigated. On this basis, the application scenarios of these emerging information technologies in modern ESP are extensively discussed. It can be foreseen that an efficient and economic ESP can be achieved by implementing these new technologies for the benefit of both policy makers and system planners.
Small-Signal Stability Analysis of Power Systems Integrated with Variable Speed Wind Generators, 2018
Grid connection of a VSWG to a power system is realized by the converter control, which normally ... more Grid connection of a VSWG to a power system is realized by the converter control, which normally adopts the current vector control algorithm. This has been introduced in Chap. 2. Implementation of current vector control needs to track the relative positions between the d − q coordinate of the converter and the common x − y coordinate of the power system in order to determine the d − q coordinate of the converter. As being illustrated by Fig. 2.8, the direction of the terminal voltage (PCC voltage) of a PMSG in x − y coordinate of the power system is normally taken as that of d axis of d − qcoordinate of the GSC of the PMSG. Figure 2.10 shows that the direction of the terminal voltage (PCC voltage) of a DFIG in x − y coordinate of the power system is often taken as that of d axis of d − q coordinate of the RSC of the DFIG. Hence, by tracking the phase of the terminal voltage of the VSWG, d − q coordinate of the converter can be determined for implementing the current vector control. This task of phase tracking is normally fulfilled by a phase locked loop (PLL).
2020 International Conference on Smart Grids and Energy Systems (SGES), 2020
This is an open access protocol distributed under the terms of the Creative Co mmo ns Attributio ... more This is an open access protocol distributed under the terms of the Creative Co mmo ns Attributio n License Creative Co mmo ns Attributio n License Project Summary Project Summary Background Rationale Background Rationale Neonatal hypoglycaemia is a common condition, particularly affecting LBW newborns, and is associated with both acute and long standing complications. Ideally, the mother can provide breast milk as soon as possible; however, in many circumstances (poor nutrition of mother, post-operative Caesarian section, etc) this may not be the case for hours or even days. If resources are available, this can be managed by providing the LBW neonate with artificial milk/donor whilst waiting for breast milk when required. However, this is often not available in resource poor countries due to expense and difficulty in production (timely clean safe water, training in how to make the milk etc). Furthermore, in resourced hospitals, glucose is monitored in at risk babies, and should they develop hypoglycemia, IV 10% dextrose can be relatively simply administered. In resource poor settings, this is challenging-firstly, glucose monitoring and then the administration of IV 10% dextrose require resources, skills and nursing that are often not available. The primary aim of this study is to assess whether the use of oral 10% dextrose, is tolerable and reduces the incidence of hypoglycaemia in LBW newborns in the absence of sufficient maternal breast milk. 10% dextrose is readily available, inexpensive and can be stored at room temperature. Objectives Objectives Our aim was to assess whether hypoglycaemia could be prevented in LBW babies with insufficient maternal breast milk (MBM), by supplementing their feed with oral 10% dextrose. Methods Methods This is a 8 months, interventional, prospective, single centre, randomised, double arm control trial on 74 newborns conducted at a district hospital in Tanzania (Tosamaganga Hospital) where Doctors with Africa-CUAMM has ongoing projects on maternal-neonatal health. LBW newborns fulfilling the inclusion criteria will be randomly allocated to either the intervention (supplemental oral 10% dextrose) or monitoring arm. Glucose will be monitored regularly in both arms and the incidence of hypoglycaemic episodes recorded together with normal vital signs. A budget of 16,000,000Tsh has been proposed for the study. Outcomes Outcomes The primary outcome will be hypoglycemia (<2•6mmol/L) in the first three days of life.
This chapter introduces modal analysis of small-signal angular stability of a power system affect... more This chapter introduces modal analysis of small-signal angular stability of a power system affected by a grid-connected DFIG. First, a method of decomposed modal analysis is proposed. The method can separately examine the impact of load flow change and dynamic interactions brought about by the grid-connected DFIG. Second, the impact of dynamic interactions introduced by the grid-connected DFIG on power system small-signal angular stability is examined comprehensively. Two indices to estimate the impact are introduced.
2017 IEEE Electrical Power and Energy Conference (EPEC), 2017
In this paper, current application and its development of flexible alternating current transmissi... more In this paper, current application and its development of flexible alternating current transmission system (FACTS) are briefly described. Targeting to solve the potential threatens in developing Jiangsu grid, feasibility for application of FACTS to improve system reliability and transfer capacity is investigated. Middle across-Yangtze-river transmission channel, southern-Suzhou system and western-Nanjing inter-city circle grid are set as the examples. The conclusions can be obtained that: with the application of FACTS, power flows in the system can be effectively controlled. The transfer capacity can be obviously improved, and induced voltage unstable problem during the severe faults such as bipolar latched in the ultra-high-voltage direct current (UHVDC) system can be prevented. Application of FACTS can also avoid the huge investment and difficult construction for the new across-river transmission channels and across-city cables. In summary, application of FACTS can prominently improve the efficiency and reliability of the system operation, and better economic and social benefits for the grid can be achieved.
Background Domestic solar PV installations in India are yet to become a valuable proposition for ... more Background Domestic solar PV installations in India are yet to become a valuable proposition for both the prosumers and utility because of the deficiencies in the formulation of the policy parameters. This paper presents a comprehensive analysis of the consumer-centric business model for rooftop solar PV installations in India. We explore areas where potential policy interventions may be introduced to improve collective stakeholder benefits and incentivize more domestic consumers to install rooftop solar panels in their premises. We propose a policy framework that seeks optimal Feed-in Tariff (FiT) rates, PV capacities and Average Billing Rates (ABRs) towards maximizing stakeholder benefits. The stakeholders considered are the consumers/prosumers and the utility. Results Case studies with three residential prosumers of different demand and generation profiles (extracted from data provided by Indian utilities) are presented. A multi-objective problem is formulated with the FiT, gener...
A conventional steady-state power flow security check only implements point-by-point assessment, ... more A conventional steady-state power flow security check only implements point-by-point assessment, which cannot provide a security margin for system operation. The concept of a steady-state security region is proposed to effectively tackle this problem. Considering that the commissioning of the increasing number of HVDC (High Voltage Direct Current) and the fluctuation of renewable energy have significantly affected the operation and control of a conventional AC system, the definition of the steady-state security region of the AC/DC power system is proposed in this paper based on the AC/DC power flow calculation model including LCC/VSC (Line Commutated Converter/Voltage Sourced Converter)-HVDC transmission and various AC/DC constraints, and hence the application of the security region is extended. In order to ensure that the proposed security region can accurately provide global security information of the power system under the fluctuations of renewable energy, this paper presents four methods (i.e., a screening method of effective boundary surfaces, a fitting method of boundary surfaces, a safety judging method, and a calculation method of distances and corrected distance between the steady-state operating point and the effective boundary surfaces) based on the relation analysis between the steady-state security region geometry and constraints. Also, the physical meaning and probability analysis of the corrected distance are presented. Finally, a case study is demonstrated to test the feasibility of the proposed methods.
It is vital to improve the stability of the power system by accurately identifying the modal para... more It is vital to improve the stability of the power system by accurately identifying the modal parameters of damped low-frequency oscillations (DLFO) and controlling the oscillation in time. A new method based on empirical mode decomposition (EMD), stochastic subspace identification (SSI), and Prony algorithms, called synthetical modal parameters identification (SMPI) method, is developed by efficiently matching the modal parameters of DLFO which are acquired from the SSI and Prony algorithm. In this approach, EMD is used for denoising the raw oscillation signals thereby enhancing the noise resistance, and then using the SSI and Prony algorithms to identify the precise modal parameters assisted by parameter matching. It is demonstrated that the proposed SMPI method holds great accuracy in identifying full modal parameters including natural frequencies, damping ratios, amplitudes, and phase angles with simulated signals with known modal parameters and real-time signals from some power ...
In view of modern power system characterized by significant inertia reduction and booming uncerta... more In view of modern power system characterized by significant inertia reduction and booming uncertainty, this letter proposes an important operational planning tool to comprehensively analyze frequency stability including both steady-state frequency and rate of change of frequency (RoCoF) issues in a probabilistic manner for the first time. The proposed generic framework can tackle various frequency-related uncertainties and accommodate different system frequency response (SFR) models. The effectiveness and efficiency of the proposed analytical probabilistic assessment are demonstrated by comparing with numerical scenario-based simulation (SBS). Index Terms-Cumulant-based theory, frequency nadir/vertex (FN/FV), rate of change of frequency (RoCoF), renewable energy.
A conventional steady-state power flow security check only implements point-by-point assessment, ... more A conventional steady-state power flow security check only implements point-by-point assessment, which cannot provide a security margin for system operation. The concept of a steady-state security region is proposed to effectively tackle this problem. Considering that the commissioning of the increasing number of HVDC (High Voltage Direct Current) and the fluctuation of renewable energy have significantly affected the operation and control of a conventional AC system, the definition of the steady-state security region of the AC/DC power system is proposed in this paper based on the AC/DC power flow calculation model including LCC/VSC (Line Commutated Converter/Voltage Sourced Converter)-HVDC transmission and various AC/DC constraints, and hence the application of the security region is extended. In order to ensure that the proposed security region can accurately provide global security information of the power system under the fluctuations of renewable energy, this paper presents four methods (i.e., a screening method of effective boundary surfaces, a fitting method of boundary surfaces, a safety judging method, and a calculation method of distances and corrected distance between the steady-state operating point and the effective boundary surfaces) based on the relation analysis between the steady-state security region geometry and constraints. Also, the physical meaning and probability analysis of the corrected distance are presented. Finally, a case study is demonstrated to test the feasibility of the proposed methods.
This paper proposes a method of probabilistic analysis to investigate the impact of stochastic un... more This paper proposes a method of probabilistic analysis to investigate the impact of stochastic uncertainty of grid-connected wind generation on power system small-signal stability. The proposed method is "analytical" in contrast to the numerical method of Monte Carlo simulation which relies on large number of random computations. It can directly calculate the probabilistic density function (PDF) of critical eigenvalues of a large-scale power system from the PDF of grid-connected multiple sources of wind power generation, thus to determine the probabilistic small-signal stability of the power system as affected by the wind generation. In the paper, an example of 16-machine power system with 3 grid-connected wind farms is used to demonstrate the application of the proposed method. The results of probabilistic stability analysis of the example power system are confirmed by the Monte Carlo simulation. It is shown that the stochastic variation of grid-connected wind generation can cause the system to lose stability even though the system is stable deterministically. The higher the level of wind penetration is, the more the probability that the system becomes unstable could be. Hence indeed penetration of stochastically variable wind generation threats stable operation of power systems as far as system small-signal stability is concerned.
In order to improve the small-signal stability of AC/DC hybrid systems containing voltagesource c... more In order to improve the small-signal stability of AC/DC hybrid systems containing voltagesource converter based high-voltage direct current (VSC-HVDC), this article extends damping torque analysis (DTA) theory to VSC-HVDC supplementary damping controller to analyze its dynamic impacts and inhibit oscillations. Firstly, this article presents the mechanism and procedure of VSC supplementary damping controller and establishes the linearized model of AC/DC system with damping controllers. On this basis, the DTA theory of VSC supplementary damping controller and the equation of damping torque index (DTI) are derived. The theory can be applied to the design of the damping controller including the selection of installation location and channel as well as the parameter tuning. Finally, case studies are carried out in two AC/DC hybrid systems containing VSC-HVDC. The simulation results verify the correctness and feasibility of DTI analysis. VSC damping controllers designed by the proposed method can effectively suppress oscillations and improve the dynamic stability of the AC/DC system. INDEX TERMS VSC-HVDC, supplementary damping controller, damping torque analysis (DTA), smallsignal stability, ac/dc system.
Oscillatory stability has received immense attention in recent years due to the significant incre... more Oscillatory stability has received immense attention in recent years due to the significant increase in power electronic converter (PEC)-interfaced renewable energy sources. Synchrophasor technology offers superior capability to measure and monitor power systems in real time, and power system operators require better understanding of how it can be used to effectively analyze and control oscillations. This article reviews state-of-the-art oscillatory stability monitoring, analysis, and control techniques reported in the published literature based on synchrophasor technology. An updated classification is presented for power system oscillations with a special emphasis on oscillations induced from PEC-interfaced renewable energy generation. Oscillatory stability analysis techniques based on synchrophasor technology are well established in power system engineering, but further research is required to effectively utilize synchrophasor-based oscillatory stability monitoring, analysis, and control techniques to characterize and mitigate PEC-induced oscillations. In particular, emerging big data analytics techniques could be used on synchrophasor data streams to develop oscillatory stability monitoring, analysis, and damping techniques.
This paper presents a novel framework for cooperative trading in a price-maker wind power produce... more This paper presents a novel framework for cooperative trading in a price-maker wind power producer, that participates in the short-term electricity balance markets. In this framework, market price uncertainty is first modeled using a price uncertainty predictor, consisting of ridge regression (RR), nonpooling convolutional neural network (NPCNN), and linear quantile regression (LQR). RR is employed to select the correlated features to the corresponding forecast day, NPCNN is employed to extract the nonlinear features, and LQR is employed to estimate the price uncertainty. Then, an improved firefly algorithm (IFA) is proposed to solve the optimization problem. IFA uses the adaptive moment estimation method to improve the convergence speed and search for the global solution. Finally, the Shapley value is employed for the profit distribution of cooperative power producers. Illustrative examples show the effectiveness of the proposed framework and optimization model
11th IET International Conference on Advances in Power System Control, Operation and Management (APSCOM 2018), 2018
Заведующая клинико-диагностической лабораторией, врач клинической лабораторной диагностики ГБУЗ «... more Заведующая клинико-диагностической лабораторией, врач клинической лабораторной диагностики ГБУЗ «КБСМП г. Краснодара» Улитина Нина Николаевна канд. биол. наук, доцент кафедры биохимии и физиологии Кубанского государственного университета г. Краснодар Кашкова Марина Дмитриевна студентка 1 курса магистратуры Кубанского государственного университета, биологического факультета, кафедры биохимии и физиологии г.
2020 IEEE 4th Conference on Energy Internet and Energy System Integration (EI2), 2020
The emerging information technologies provides an opportunity for supporting the planning of ener... more The emerging information technologies provides an opportunity for supporting the planning of energy industry development. This paper presents an overview on the application of the novel information technologies including big data, artificial intelligence (AI), cloud computing and virtual reality (VR) in the modern energy strategy planning (ESP). Firstly, the concept and current challenges of ESP is briefly reviewed and some typical information technologies which might be suitable for modern ESP are summarized. Secondly, the major technical needs of modern ESP are investigated. On this basis, the application scenarios of these emerging information technologies in modern ESP are extensively discussed. It can be foreseen that an efficient and economic ESP can be achieved by implementing these new technologies for the benefit of both policy makers and system planners.
Small-Signal Stability Analysis of Power Systems Integrated with Variable Speed Wind Generators, 2018
Grid connection of a VSWG to a power system is realized by the converter control, which normally ... more Grid connection of a VSWG to a power system is realized by the converter control, which normally adopts the current vector control algorithm. This has been introduced in Chap. 2. Implementation of current vector control needs to track the relative positions between the d − q coordinate of the converter and the common x − y coordinate of the power system in order to determine the d − q coordinate of the converter. As being illustrated by Fig. 2.8, the direction of the terminal voltage (PCC voltage) of a PMSG in x − y coordinate of the power system is normally taken as that of d axis of d − qcoordinate of the GSC of the PMSG. Figure 2.10 shows that the direction of the terminal voltage (PCC voltage) of a DFIG in x − y coordinate of the power system is often taken as that of d axis of d − q coordinate of the RSC of the DFIG. Hence, by tracking the phase of the terminal voltage of the VSWG, d − q coordinate of the converter can be determined for implementing the current vector control. This task of phase tracking is normally fulfilled by a phase locked loop (PLL).
2020 International Conference on Smart Grids and Energy Systems (SGES), 2020
This is an open access protocol distributed under the terms of the Creative Co mmo ns Attributio ... more This is an open access protocol distributed under the terms of the Creative Co mmo ns Attributio n License Creative Co mmo ns Attributio n License Project Summary Project Summary Background Rationale Background Rationale Neonatal hypoglycaemia is a common condition, particularly affecting LBW newborns, and is associated with both acute and long standing complications. Ideally, the mother can provide breast milk as soon as possible; however, in many circumstances (poor nutrition of mother, post-operative Caesarian section, etc) this may not be the case for hours or even days. If resources are available, this can be managed by providing the LBW neonate with artificial milk/donor whilst waiting for breast milk when required. However, this is often not available in resource poor countries due to expense and difficulty in production (timely clean safe water, training in how to make the milk etc). Furthermore, in resourced hospitals, glucose is monitored in at risk babies, and should they develop hypoglycemia, IV 10% dextrose can be relatively simply administered. In resource poor settings, this is challenging-firstly, glucose monitoring and then the administration of IV 10% dextrose require resources, skills and nursing that are often not available. The primary aim of this study is to assess whether the use of oral 10% dextrose, is tolerable and reduces the incidence of hypoglycaemia in LBW newborns in the absence of sufficient maternal breast milk. 10% dextrose is readily available, inexpensive and can be stored at room temperature. Objectives Objectives Our aim was to assess whether hypoglycaemia could be prevented in LBW babies with insufficient maternal breast milk (MBM), by supplementing their feed with oral 10% dextrose. Methods Methods This is a 8 months, interventional, prospective, single centre, randomised, double arm control trial on 74 newborns conducted at a district hospital in Tanzania (Tosamaganga Hospital) where Doctors with Africa-CUAMM has ongoing projects on maternal-neonatal health. LBW newborns fulfilling the inclusion criteria will be randomly allocated to either the intervention (supplemental oral 10% dextrose) or monitoring arm. Glucose will be monitored regularly in both arms and the incidence of hypoglycaemic episodes recorded together with normal vital signs. A budget of 16,000,000Tsh has been proposed for the study. Outcomes Outcomes The primary outcome will be hypoglycemia (<2•6mmol/L) in the first three days of life.
This chapter introduces modal analysis of small-signal angular stability of a power system affect... more This chapter introduces modal analysis of small-signal angular stability of a power system affected by a grid-connected DFIG. First, a method of decomposed modal analysis is proposed. The method can separately examine the impact of load flow change and dynamic interactions brought about by the grid-connected DFIG. Second, the impact of dynamic interactions introduced by the grid-connected DFIG on power system small-signal angular stability is examined comprehensively. Two indices to estimate the impact are introduced.
2017 IEEE Electrical Power and Energy Conference (EPEC), 2017
In this paper, current application and its development of flexible alternating current transmissi... more In this paper, current application and its development of flexible alternating current transmission system (FACTS) are briefly described. Targeting to solve the potential threatens in developing Jiangsu grid, feasibility for application of FACTS to improve system reliability and transfer capacity is investigated. Middle across-Yangtze-river transmission channel, southern-Suzhou system and western-Nanjing inter-city circle grid are set as the examples. The conclusions can be obtained that: with the application of FACTS, power flows in the system can be effectively controlled. The transfer capacity can be obviously improved, and induced voltage unstable problem during the severe faults such as bipolar latched in the ultra-high-voltage direct current (UHVDC) system can be prevented. Application of FACTS can also avoid the huge investment and difficult construction for the new across-river transmission channels and across-city cables. In summary, application of FACTS can prominently improve the efficiency and reliability of the system operation, and better economic and social benefits for the grid can be achieved.
Background Domestic solar PV installations in India are yet to become a valuable proposition for ... more Background Domestic solar PV installations in India are yet to become a valuable proposition for both the prosumers and utility because of the deficiencies in the formulation of the policy parameters. This paper presents a comprehensive analysis of the consumer-centric business model for rooftop solar PV installations in India. We explore areas where potential policy interventions may be introduced to improve collective stakeholder benefits and incentivize more domestic consumers to install rooftop solar panels in their premises. We propose a policy framework that seeks optimal Feed-in Tariff (FiT) rates, PV capacities and Average Billing Rates (ABRs) towards maximizing stakeholder benefits. The stakeholders considered are the consumers/prosumers and the utility. Results Case studies with three residential prosumers of different demand and generation profiles (extracted from data provided by Indian utilities) are presented. A multi-objective problem is formulated with the FiT, gener...
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