Full Power System Research Articles

Evaluation and Upscaling of Impregnated La0.20Sr0.25Ca0.45TiO3 Fuel Electrodes for Solid Oxide Electrolysis Cells

Recent research into Rh and Ce0.80Gd0.20O1.90-impregnated La0.20Sr0.25Ca0.45TiO3 fuel electrodes for solid oxide fuel cells has demonstrated the high-stability of these material sets to a variety of harsh operating conditions at small scales (1 cm2 active area button cells), as well as commercial scales (100 cm2 cells) in short stacks (5 cells) and full micro-combined heat and power systems (60 cells). In this work, the authors present a comprehensive evaluation of the ability of these novel titanate-based materials to function as fuel electrodes in solid oxide electrolysis cells (SOECs). Short-term and durability testing of button cell scale SOECs highlighted the limited stability of lanthanum strontium manganite-based air electrodes, under CO2 and steam electrolysis conditions, with lanthanum strontium cobaltite ferrite-based air electrodes offering improved degradation characteristics. Upscaling of this optimized cell chemistry to a 16 cm2 active area SOEC and testing under CO2, CO2/H2O and H2O electrolysis conditions demonstrated encouraging performance over a period of ∼600 h, with stable co-electrolysis performance at ∼−7.5 A at 1.47 V for the first 100 h.

Evaluation and Upscaling of Impregnated La0.20Sr0.25Ca0.45TiO3 Fuel Electrodes for Solid Oxide Electrolysis Cells Under H2O, CO2 and Co-Electrolysis Conditions

Recent research into Rh and Ce0.80Gd0.20O1.90-impregnated La0.20Sr0.25Ca0.45TiO3 fuel electrodes for solid oxide fuel cells has demonstrated the high-stability of these material sets to a variety of harsh operating conditions at small scales (button cells with 1 cm2 active area), as well as full commercial scales (100 cm2 cells) in short stacks (5 cells) and full micro-combined heat and power systems (60 cells). In this work, the authors present a comprehensive evaluation of the ability of these novel titanate-based materials to function as fuel electrodes in solid oxide electrolysis cells (SOECs). Short-term and durability testing of button cell scale SOECs, under CO2 and steam electrolysis conditions, highlighted the limited stability of lanthanum strontium manganite-based air electrodes with lanthanum strontium cobaltite ferrite-based air electrodes offering improved degradation. Upscaling of this optimized cell chemistry to a 16 cm2 active area SOEC and testing under CO2, CO2/steam and steam electrolysis conditions demonstrated encouraging performance over a period of ~600 hours.

Systematic design and power management of a novel parallel hybrid electric powertrain for heavy-duty vehicles

A novel multi-degree-of-freedom parallel hybrid propulsion system with multi-gear for heavy-duty vehicles is proposed to optimize fuel economy, driving comfort, and dynamic performance. The system has a compact structure and high integration. The detailed design and the power flow of the parallel hybrid propulsion system are introduced. The full power system prototype is designed and assembled. The control methods for the driving torque compensation and energy management are investigated. The simulated results of the parallel hybrid propulsion system are presented. The propulsion system power is not interrupted during gear shifting with the torque compensation control. The jerk of the vehicle is also reduced during shifting. The internal combustion engine can work more efficiently in the hybrid propulsion mode with the equivalent consumption minimization strategy. The purpose of this paper is to provide a hybrid driving scheme for commercial vehicles.

Implementation of The Internet of Things for Public Street Light

Currently, there are still many street lighting systems with electrical resources that use a full power system or a time system to regulate the power issued by the lamp so that in terms of the costs incurred for the lamp, it is also quite large. And in terms of maintenance, for now the problematic street lighting is still using conventional methods, namely waiting for damage reports from the field directly so that the handling of damaged lamps is very slow. Based on these problems, a street lighting lamp with automatic control will be designed that can adjust the light intensity and report the status of the lamp online through the Internet of Things (IoT) website which can be accessed using a smartphone or PC connected to the internet so that energy use and handling actions will be carried out. damage is more efficient. In this study, an automatic PJU was designed with a Passive Infrared Receiver (PIR) sensor to detect the presence or absence of objects around the lamp and an ESP module to connect the hardware to the internet network via a Wi-Fi connection . For the automatic system of turning on and off the lights based on bright and dark conditions of sunlight using a Photocell containing a Light Dependent Resistor (LDR) . With the use of this system, it can be proven that the use of Passive Infrared Receiver (PIR) sensors and Thingspeak website-based monitoring can streamline spending on electricity financing and accelerate the handling of lamp damage.

Optimal PMU Placement in the Presence of Conventional Measurements

This article presents a novel method for optimal phasor measurement unit placement (OPP) for full power system observability in the presence of conventional measurements. The method considers eligible PMU placements that may be omitted by existing OPP methods and hence may provide a better solution and can guarantee that the PMU placement can restore network observability. This is achieved by creating a new observability criterion and a network transformation scheme. The new observability criterion uses injection and zero injection measurements to improve the solution and the network transformation scheme reduces the size of the OPP problem and is a prerequisite for applying the proposed observability criterion. The OPP problem is solved using binary integer linear programming (BILP) or binary integer linear programming (BILP). Therefore, the proposed OPP method can be easily combined with other OPP methods, considering other constraints/scenarios using BILP, such as OPP considering PMU current channel limits. The new method is tested using simulations of the IEEE 14-, 118-, and 2736-bus test systems. These results show that the proposed new method is feasible in terms of execution time, is free of solutions that fail to make the system fully observable, and is capable of identifying optimal placement solutions that may be overlooked by existing OPP methods.

Initial Propulsion System Study for the Futuristic Hyperloop Transportation System: Design, Modeling, and Hardware in the Loop Verification

Recently, the proposal for a futuristic mode of transportation known as the Hyperloop has been popularized. Currently, there are only some reports regarding the design of the Hyperloop. More specifically, reports regarding the propulsion system design methodology for Hyperloop is minimal. Thus, this paper provides an initial steppingstone to modeling and simulation study for the propulsion system in a Hyperloop. The main contribution of this study is to provide a relatively simple design methodology for any future Hyperloop endeavors. This is shown using state of the art simulators to aid in designing the propulsion system. The design revolves around the linear synchronous motor based on field-oriented control through a three – phase inverter. PSIM is used to develop the model and design the full power system and controller. This includes the DC-DC converter, battery system model, three – phase inverter, and the motor controller. The motor used for modelling is a rotary permanent magnet synchronous motor. Finally, hardware in the loop technology is used to verify and validate the design. The controller design is tested through a Texas Instrument digital signal processor. The real time verification shows matching results with the offline simulation model.

High step-up isolated DC-DC converter based on resonant network for DC offshore wind farms

At present, the use of DC convergence and DC transmission (abbreviated as all DC) is recognized as the most effective technical solution and inevitable trend to solve the flexible access of large-scale new energy generation. However, the high-voltage and large-capacity DC-DC converters used in the DC convergence of the full DC system are still in the preliminary research stage. This paper presents a high voltage and large capacity isolated DC-DC converter topology, which is composed of three-stage boost circuit. The simulation results show that the topology can increase the output voltage of wind turbine from 1kV to 320kV, effectively improve the boost ratio of converter, and provide a theoretical basis for the realization of full DC offshore wind power system.

A Novel Algorithm for Optimal Phasor Measurement Unit Placement for Full Power System Topological Observability

A Novel Algorithm for Optimal Phasor Measurement Unit Placement for Full Power System Topological Observability

Robust Scale-Free Synthesis for Frequency Control in Power Systems

The ac frequency in electrical power systems is conventionally regulated by synchronous machines. The gradual replacement of these machines by asynchronous renewable-based generation, which provides little or no frequency control, increases system uncertainty and the risk of instability. This imposes hard limits on the proportion of renewables that can be integrated into the system. In this paper, we address this issue by developing a framework for performing frequency control in power systems with arbitrary mixes of conventional and renewable generation. Our approach is based on a robust stability criterion that can be used to guarantee the stability of a full power system model on the basis of a set of decentralized tests, one for each component in the system. It can be applied even when using detailed heterogeneous component models, and can be verified using several standard frequency response, state-space, and circuit theoretic analysis tools. Furthermore, the stability guarantees hold independently of the operating point, and remain valid even as components are added to and removed from the grid. By designing decentralized controllers for individual components to meet these decentralized tests, every component can contribute to the regulation of the system frequency in a simple and provable manner. Notably, our framework certifies the stability of several existing (nonpassive) power system control schemes and models, and allows for the study of robustness with respect to delays.

A new real-time multi-agent system for under frequency load shedding in a smart grid context

Automatic under frequency load shedding schemes need to be carefully designed in order to reduce the risk of widespread system collapse. This paper proposes a centralized hierarchical multi-agent system that coordinates various stages of monitoring and decision making processes. The main contribution is to improve traditional contingency response algorithms such as load shedding schemes, taking advantage of the future smart grid infrastructure. The multi-agent system seeks for a minimum amount of load disconnection in a short period of time, causing the least possible disturbance in the system frequency. A hardware-in-the-loop simulation of a full electric power system using a real time digital simulator was utilized. The solution was embedded in a real time system, consisting of hardware and software, to test and validate the proposed methodology. In addition, the studied methodology was compared with two other load shedding philosophies through a load shedding metric score. Shedding was carried out in a single step and the amount of disconnected load was close to the dynamic power unbalance. The results show that it is possible to improve the traditional load shedding philosophy schemes and use advanced communication infrastructure, monitoring and embedded processing capabilities to provide better stability and reduce unnecessary load disconnections from the system.

Stability of a Switched Mode Power Amplifier Interface for Power Hardware-in-the-Loop

Power hardware-in-the-loop (PHIL) is an attractive, real-time system testing and validation technique. Virtual models can be replaced with physical equipment to emulate system integration testing, and perform model validation without the cost and risk of a full scale power system. Power amplifiers are the principal components that facilitate the power interface between the physical and the virtual systems. This necessary interfacing introduces dynamics that do not exist in the real system and is the source of stability and accuracy issues affecting PHIL applications. This paper presents a stability analysis of a practical PHIL system based on the ideal transformer model interface algorithm that utilizes a voltage source converter for power amplification. A systematic approach to evaluate the expected stability characteristics of PHIL experiments is developed. The analysis in this paper shows that in a practical system, the power amplifier's filter, sampling, and measurement filtering are all shown to influence the stability in a counterintuitive way, leading to a nonmonotonic stability characteristic. An experimental PHIL platform based on a real-time digital simulator real-time computer has been used to validate the analysis and confirm the effects of the practical interface. Switching dead-time is also shown to have a significant stabilizing effect.

Module and System Considerations to Maximize Performance Advantages of SiC Power Devices

This paper extends a previously presented SiC power module design philosophy to critical, higher-level components for increased system performance, namely the DC bussing and DC link capacitor design. The DC bussing is essential to connect the DC bulk capacitors to the high-speed power modules and it is imperative that low inductance is maintained while current carrying capability and temperature be maintained. Often, high frequency capacitors are added to systems to increase performance by compensating for extra stray inductance that the DC bussing can introduce. However, issues that may arise by doing such are presented and it is shown that the best solution is to optimize the DC bus structure rather than compensate for a poor design. Finally, the implemented bussing is shown and full power system results presented for the inverter stack-up design.

Localized Transient Stability (LTS) Method for Real-time Localized Control

<p>Very recently, a new methodology was introduced solely for the purpose of real-time localized control of transient stability. The proposed new method is based on the localized transient stability of a power system. This is completely a new idea in transient stability. In this method, the post-fault power system is represented by a two-generator localized power system at the site of each individual generator. If each of these localized power systems reaches its respective stable equilibrium, then the full power system also reaches its stable equilibrium. Therefore, in terms of real-time localized control of transient stability, if each of the localized power systems is driven to its respective stable equilibrium by local control actions with local computations using the locally measured data, then the full power system is driven to its stable equilibrium. Thus the method can be easily implemented for real-time localized control of transient stability. In this paper, the details of the mathematical formulations are presented. Some interesting test results on the well-known New England 39-bus 10-generator system are also presented in this paper to demonstrate the potential of the proposed method for use in real-time localized control of transient stability.</p><p> </p>

Identification of the Most Effective Point of Connection for Battery Energy Storage Systems Focusing on Power System Frequency Response Improvement

With the massive penetration of intermittent generation (wind and solar), the reduction of Electrical Power Systems’ (EPSs) inertial frequency response represents a new challenge. One alternative to deal with this scenario may be the application of a Battery Energy Storage System (BESS). However, the main constraint for the massive deployment of BESSs is the high acquisition cost of these storage systems which in some situations, can preclude their use in transmission systems. The main goal of this paper is to propose a systematic procedure to include BESSs in power system aiming to improve the power system frequency response using full linear models and geometric measures. In this work, a generic battery model is developed in a two-area test system with assumed high wind penetration and full conventional generators models. The full power system is linearized, and the geometric measures of controllability associated with of the frequency regulation mode are estimated. Then, these results are used to identify the most effective point of connection for a BESS aiming at the improvement of the power system frequency response. Nonlinear time-domain simulations are carried out to evaluate and validate the results.

Integrated Mutation Strategy With Modified Binary PSO Algorithm for Optimal PMUs Placement

Optimal phasor measurement units (PMUs) placement refers to the strategic placement of PMUs to achieve the full observability of power systems with a minimum number of PMUs. A strategic placement is needed because of the economic or technical restriction that hinders the deployment of PMUs on every bus. A modified version of the binary particle swarm optimization method is proposed in this paper by integrating a mutation strategy and the V-shaped sigmoid function for placing the PMUs that maintains the full power system observability in the presence of zero-injection bus, single PMU loss, and PMU's channel limits while maximizing the measurement redundancy. The solution that has the highest measurement redundancy was selected as the best placement of PMUs. The use of mutation strategy and V-shaped sigmoid function in this paper improves the population diversity, thereby minimizing the chance of the particles being trapped in the local optima, consequently leading to a quality solution. In order to validate its effectiveness, the results obtained by the proposed method are compared with other published techniques to demonstrate the accuracy and validity of the proposed technique. The results of the IEEE 300-bus system show that the proposed method effectively managed to reduce the number of PMUs needed.

A Two-Stage State Estimator for Dynamic Monitoring of Power Systems

Fault recorders can track the transients in the power system during a fault. However, they cannot provide a wide area picture of the power system operating condition. The provision to track the transients is of great interest for the power system operators. In this paper, a two-stage state estimator (SE), based on both conventional and phasor measurement unit (PMU) measurements, is presented. The estimator is able to track the dynamics of the power system states during a fault. The advantage of the proposed SE is that it does not require full power system observability by the PMU measurements. The two-stage SE was successfully tested on the IEEE 14 and 118 bus systems.

Synthesizing a tokamak plasma magnetic control circuit with allowance for the characteristics of the power supply system

The problem of controlling the position and shape of the plasma in a tokamak is considered. Although a great many works have been devoted to this problem, most of them use relatively simple models of a power system that acts as an actuator. Full power system models are rarely used, even during simulations. A mathematical model of a thyristor converter, one of the main elements of a power system, is proposed here in the form of a switching system. An algorithm based on a predictive control model is described. A numerical simulation of the model system’s operation is performed.

Modeling and experimental validation of hybrid proton exchange membrane fuel cell/battery system for power management control

Hybrid proton exchange membrane fuel cell (PEMFC)/battery power system is regarded as one of the most potential alternative power solutions in vehicular application since its low or zero emission and long life comparing to conventional engine and stand-alone battery pack. As the hybridization may reduce the fuel efficiency and battery efficiency because of interconnected power distribution, elaborate power management is prerequisite. This study presents DC/DC power converters including unidirectional boost and bidirectional types by using time delay control (TDC) to implement power management for hybrid power system. The bidirectional DC/DC converter operation mode is automatically switched by power management rules with battery state-of-charge (SOC) constraint. MATLAB/Simulink model of full hybrid power system is constructed to simulate the efficacy of proposed algorithm. Proportional-integral control (PIC) is employed in order to compare the control performance. Experimental validation is also performed with commercial PEMFC Horizon H-100, lithium-ion battery pack, DC/DC unidirectional and bidirectional converter prototype with National Instrument (NI) LabVIEW.

Wide Area Inter-Area Oscillation Monitoring Using Fast Nonlinear Estimation Algorithm

This paper presents the results of the development of Smart Grid transmission network applications in the Great Britain (GB) power system. A new Wide Area Monitoring System (WAMS) application for monitoring inter-area oscillations is developed. The core of this novel application is a fast nonlinear algorithm for the real-time estimation of the dominant inter-area oscillation mode, which processes GPS synchronized information obtained from Phasor Measurement Units (PMUs) installed in the power system. It is based on the Newton-Type Algorithm (NTA), an efficient parameter estimator. The paper focuses on the practical application of the new WAMS application: two data sets were tested, one based on computer simulations and the other based on real-life data records. The computer simulated oscillatory signals were obtained through dynamic simulations of the full GB power system model consisting of over 200 generators. The real-life data records used information collected by the FlexNet Wide Area Monitoring System (FlexNET-WAMS) installed in the GB network. Based on these data records, the features of inter-area oscillations in the GB network are drawn.

Max Covering Phasor Measurement Units Placement for Partial Power System Observability

Phasor Measurement Units (PMUs) are key elements in secure monitoring and control operations of the power network. Most existing algorithms consider the full power grid observability for the PMU placement problem with the objective of minimizing the cost assuming the availability of the resources. This paper presents a PMU placement approach to ensure maximum coverage of the power network for the case where the resources are limited and full observability is not achievable. Given the limited number of PMUs the model aims to find the best placement in order to reach the maximum coverage and if possible the full power system observability. The problem formulated as an integer linear programming (ILP) model and solved for optimality. The optimization model is solved for IEEE 14, 30, 57, 118 and 2383 standard test systems incorporating the zero-injection buses. The reliability of the power system has been evaluated for the placement results reaching full network observability. The results show that with sufficient resources in hand the developed maximum covering model is comparable to the existing algorithms for full power network observability.