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Previous research has proved that Mobile Battery Energy Storage (MBES) can play a pivotal role in achieving resiliency goals in distribution networks besides sustainability purposes. The missing links in the practical deployment of this new flexibility resource are the discontinuity between normal and emergency operating states in addition to the high computational burden. Accordingly, a new rolling-horizon operation model for a fleet of truck-mounted mobile batteries (TMMBs) employed in a joint transportation-distribution network is proposed. The model can effectively handle and switch between normal and emergency states by integrating a new schedule memory concept into the upcoming horizons. The spatial and temporal dynamics of the TMMBs, along with the transportation time and cost constraints, are modeled by a novel linear and computationally affordable formulation. The model runtime is further targeted by proposing a two-stage optimization model to detach transportation network calculations from the distribution grid. Additionally, a lexicographic multi-objective paradigm is used to ensure a maximum resiliency plan at the minimum expenses during emergencies. The model considers outage and congestion change of the road traffic beyond the forecasted values besides network uncertainties. Implementing the model on a test case proves its functionality in dealing with diverse network situations. [ABSTRACT FROM AUTHOR]

The microgrid operation is addressed in this article based on a multicarrier energy hub. Natural gas, electricity, heating, cooling, hydrogen, carbon dioxide, and renewable energies are considered as the energy carriers. The designed microgrid optimizes and utilizes a wide range of resources at the same time including renewables, electrical storage, hybrid storage, heating-cooling storage, electric vehicles (EVs) charging station, power to gas unit, combined cooling-heating-power, and carbon capture-storage. The purpose is to reduce the environmental pollutions and operating costs. The resilience and flexibility of the energy hub is also improved. Vehicle to grid and fully-partial charge models are incorporated for EVs to improve the system resilience and supplying the critical loads following events. Different events are modeled to evaluate the system resilience. The model is expressed as a stochastic mixed integer linear programming problem. Both active and reactive powers are modeled. The microgrid is simulated under four different cases. The results show that the multitype energy storages reduce the annual cost of energy while the integrated charging station can decrease the load shedding. [ABSTRACT FROM AUTHOR]

This article proposes a unified solution to address the energy issues in net-zero energy building (ZEB), as a new contribution to earlier studies. The multicarrier energy system, including hydro-wind-solar-hydrogen-methane-carbon dioxide-thermal energies is integrated and modeled in ZEB. The electrical sector is supplied by hydro-wind-solar, combined heat and power (CHP), and pumped hydro storage (PHS). The thermal sector is supplied by CHP, thermal boiler, and electric heating. The hydrogen storage system and Methanation process operate as the interface energy carriers between the electrical and thermal sectors. The carbon dioxide (CO2) of the ZEB is captured and fed into the Methanation process. The purpose is minimizing the released CO2 to the atmosphere while all the electrical-thermal load demands are successfully supplied considering events and disruptions. The model improves simultaneously the energy resilience and minimizes the environmental pollutions. The results demonstrate that the developed model reduces the CO2 pollution by about 33 451 kg per year. The model is a resilient energy system that can handle all failures of components. The model can efficiently handle 26% increment in the electrical loads and 110% increment in the thermal loads. [ABSTRACT FROM AUTHOR]

The delayed operation of distance relays zone-2 element for the faults at the end of the line is excessive. It reduces the fault clearing speed and therefore, is one of the main factors that can endanger power system stability. This paper proposes an impedance-based scheme for discrimination between the last 20% of the line length faults and the adjacent line faults, which are covered by the relay zone-2. The suggested non-pilot scheme uses a modified fault location formula for the accelerated zone-2 operation of distance relays. The negative- and zero-sequence components of local signals are utilized to calculate the accurate fault location after the remote circuit breaker (CB) operation. The proposed algorithm is independent of fault resistance, power flow direction, pre-fault condition, and it can clearly distinguish internal faults from the adjacent line faults. Simulation results show that the proposed method can identify the remote CB operation and thus can accelerate the tripping of zone-2 within a very short time for different fault locations, fault types, fault resistances, and load angles. Also, accurate fault location has been achieved under all simulation conditions. [ABSTRACT FROM AUTHOR]

Single-phase auto-reclosing (AR) scheme is widely employed in extra high voltage (EHV) transmission networks to quench transient faults without completely removing the faulted transmission line (TL). Long EHV TLs are commonly equipped with shunt reactors to reduce the Ferranti effect overvoltages. It is common practice to disconnect these reactors under the heavy load periods during the year. Considering this point, the AR technique should be able to work properly not only when the TL shunt reactors are in service, but also when they are disconnected. This paper puts forward a novel adaptive single-phase AR approach for shunt compensated TLs based on the general mathematical model of faulted phase voltage waveform after the line isolation, which is obtained by analytical analysis conducted on the TL's equivalent circuit. The effect of capacitor voltage transformer (CVT) on the voltage measurement is taken into account using a proper model for the CVT. Performing some data processing on the faulted phase measured voltage, useful features are extracted which are used by the support vector machine classifier to reliably detect the arc extinction instant. The proposed approach performance is evaluated by extensive simulation studies, accounting for different TL compensation schemes, transposition configurations, and arc conditions. [ABSTRACT FROM AUTHOR]

In this article, a multilevel inverter (MLI) scheme is proposed for 9-phase pole phase modulated induction motor (PPMIM) drives. The proposed inverter scheme is realized with the help of three 3-phase four-leg inverters. In 3-phase 12-pole mode (3PH-12PO), the proposed MLI supplies a 3-level voltage for each phase winding of the PPMIM drive with an improved harmonic profile, which results in better torque ripple. In this mode, the PPMIM drive performance is analyzed with a level shifted as well as phase shifted carrier based space vector pulse width modulation (SVPWM) techniques. On the other hand in 9-phase 4-pole mode (9PH-4PO), with help of phase grouping concept a 3-phase SVPWM implemented for enhancing the linear modulation of the 9-phase PPMIM drives by 15.4%. The fourth leg present in each 3-phase four-leg inverter is used effectively for suppressing the circulating currents in phase windings during 9PH-4PO operation. The proposed MLI is efficient to operate the PPMIM drive in both normal as well as fault conditions with rated power/torque. The proposed MLI-fed PPMIM drive performance with open circuit/short circuit of switch and source fault conditions are analyzed. The proposed MLI scheme is validated with the Ansys Maxwell finite element method (FEM) as well as laboratory testbed on a 5-hp 9-phase PPMIM drive under normal as well as open circuit switch/source fault conditions. [ABSTRACT FROM AUTHOR]

Advances in renewable energy recourses technologies have paved the way for increased utilization of DC grids in modern power systems. In particular, high voltage DC (HVDC) transmission cables are used to harvest offshore energy. Since failure diagnosis and repair of the buried offshore cables under the sea bed involve quite laborious tasks, accurate fault location is of vital importance. This paper proposes a novel fault location method based on the synchronized measurement of conductors and sheaths currents in each terminal without requiring the voltage signal. Unlike the traveling-wave-based methods, the proposed method is developed for multi-terminal HVDC systems without requiring any high precision measurement infrastructure. The proposed method can be implemented for different system topologies as well as fault resistance and fault distance. The fault location method can provide accurate results even if 10 ms time window samples are imported into the proposed algorithm. In addition, accuracy of the fault location using the proposed method is not affected significantly by noisy condition. Different test systems have been simulated to evaluate performance of the proposed method in various scenarios. Obtained results confirm that the proposed practical method can provide the accurate fault location for all different scenarios and conditions. [ABSTRACT FROM AUTHOR]

The incorporation of distributed generation (DG) units in distribution network voltage control may create operational conflicts with other conventional voltage control devices. Structural changes of networks can also increase the possibility to create control interactions. Control rules-based voltage control methods are not suitable for large scale networks where large number of control choices are available. Similarly, optimization-based voltage control methods are impractical to implement since many control variables have to be used to obtain the optimal solution. Therefore in this paper, a new technique for choosing a global group of the most effective control variables considering the ones with low cost is proposed for voltage regulation in distribution networks. This technique is based on the concept of electrical distances between the voltage control devices and network nodes to derive a correction index (CI). The index represents the level of effectiveness of each control variable with respect to all violated voltages. The index is implemented in two phase algorithms (top–down and bottom-up) to identify the global group of control variables. The proposed technique takes into consideration five aspects: the effectiveness, availability, and cost of the control variables as well as the structural changes of networks and the coordination between control variables to simultaneously eliminate the violation in the voltages. The technique is fast and suitable to be implemented for online voltage control. The proposed method is successfully examined on the modified IEEE 123 distribution system under different scenarios. [ABSTRACT FROM AUTHOR]

The fault resistance and infeeded currents from tapped transmission lines are the two main challenges to establish correct fault location estimation in multi-terminal transmission lines. Also, fault location estimation in double-circuit lines is more complicated than single-circuit lines due to the effect of mutual coupling and inter-circuit faults. This paper proposes a negative-sequence network-based method to estimate the fault location of double-circuit multi-terminal transmission lines. In the presented method, signals are measured in the relay location and then, communication links are not required as it uses only one end measurements. Also, in conventional distance relays, six elements are needed to calculate the fault location in all types of faults. Furthermore, in this method, by using only one element for each transmission line, accurate fault location can be estimated. Also, high fault resistance, mutual coupling, and infeeded currents from tapped transmission lines do not have impact on the performance of the presented scheme. To investigate the effects of the line shunt capacitances on the proposed method, a PI model of the transmission lines is used in all the investigations. Simulation results carried out using MATLAB software indicate that the proposed scheme is able to produce excellent performance for the fault location estimation. [ABSTRACT FROM AUTHOR]

This paper presents a new approach in monitoring of a power distribution system. It uses the bus voltage and injected current to extract the apparent impedance seen from the measuring unit location. Then the apparent impedance variation is used for the monitoring of different electrical quantities of the feeder such as feeder power factor, and the minimum and maximum of active and reactive power flow. This paper also presents the mathematics for defining the monitoring zone on the R-X plane to detect those parameters variations. The proposed method was tested with the unbalanced distribution system feeder loading, distributed and lumped model of solar, and wind power generations. OpenDSS and MATLAB are used to test the effectiveness of the method with the IEEE 8500 node test feeder. The dynamic performance of the proposed method is studied for online monitoring of the reactive power capability requirement of a Canadian utility for a wind farm integrated to the system. The results show that the monitoring method based on the apparent impedance has a good capability to detect different operation conditions. In addition, the simplicity of the proposed method allows easy application of it in smart grid and traditional distribution system. [ABSTRACT FROM PUBLISHER]

The integration of renewable energy resources (RESs) in power systems poses many research challenges. Research shows that the RES output may exceed the consumed power during the day. Consequently, the direction of the power flow on distribution lines can be reversed during some periods. As the voltage regulator is normally designed for unidirectional power flow, this may cause voltage violations on the distribution feeder. Therefore, most utilities try to set a penetration level (PL) limit for safe operation. On the other hand, time varying and unbalanced loading are the main characteristics of distribution systems. Moreover installation of intermittent and nondispatchable photovoltaic (PV) devices increases the control problems of distribution system. This paper presents an impedance-based monitoring method for detection of distribution system current behavior. It will be shown that by utilizing this monitoring technique, not only the small variation of PV PL can be easily detected, but also some fast transients such as the effect of cloud movement on PV system can be monitored. This monitoring technique employs only local measurements of bus voltages and line current to measure the apparent impedance seen at the installation point. The practical application of measured impedance as a monitoring technique shows its effectiveness for distribution system monitoring in presence of various PV PL. [ABSTRACT FROM PUBLISHER]

This paper presents coordinated secondary voltage control based on partitioned power network and decentralized controllers designed for each region. The elements of control are installed on pilot buses (critical point for voltage control in each region). The aim is coordination among elements of control in each region or between different regions to regulate voltage of buses and increase the security of the power network. The elements of control are considered as nodes of a graph and reactive power will be transferred through edges of this graph. This gives capability of transfer of reactive power between regions in case of voltage violations in a special region that cannot be regulated by controllers installed on that region. The control uses decentralized controllers to eliminate voltage violations resulting from load variations and disturbance in the power network. The methodology is applied to the IEEE 118-bus network. The results show and verify the performance of coordinated control scheme to regulate the voltage and to avoid propagation of contingency between regions. [ABSTRACT FROM PUBLISHER]

This paper investigates a secondary voltage control based on a graph partitioning method. The method divides the power system into regions to eventually prevent the propagation of disturbances and to minimize the interaction between these regions. The optimized number of regions is found based on the bus voltage sensitivity to disturbances being applied to loads in each region. Then, a number of representative buses are labelled as pilot buses displaying the critical point for voltage control in each region. The control uses decentralized controllers to eliminate voltage violations resulting from load variations and disturbances in the system. The decentralized controllers are implemented by fuzzy logic which is trained via offline simulations; they inject required reactive power into the regions to correct voltage violations. The methodology is applied to the IEEE 118-bus network. The results show the performance and ability of graph partitioning and fuzzy secondary voltage control to regulate the voltage and to avoid propagation of disturbances between regions. [ABSTRACT FROM PUBLISHER]

In this paper, an intelligent cooperative control and path-following algorithm is proposed and tested for a group of mobile robots. The core of this algorithm uses a fuzzy model, which mimics human thought to control the robot's velocity, movement, and group behavior. The designed fuzzy model employs two behaviors: path following and group cooperation. Hierarchical controllers have also been developed based on fuzzy and proportional integral derivative to instruct the robots to move in a group formation and follow specific paths. As the robots move along individual predetermined paths, the designed algorithm adjusts their velocities so that the group arrives at their target points within the same time duration regardless of the length of each individual path. The fuzzy rules applied to the robots are defined by the kinematics limitation, which is bounded by both linear and angular velocities and the length and curvature of the individual paths. The experimental results of three mobile robots traveling on different paths are presented to show the accuracy of obtaining control and cooperation by using the fuzzy algorithm. [ABSTRACT FROM PUBLISHER]