Open Point Research Articles

Research on the Application of SOP in Multi-Station Integrated System

The current large-scale access to distributed power and the rapid growth of electric vehicles are seriously affecting the reliability of distribution networks. The new multi-station fusion technology based on the flexible interconnection of the distribution network can effectively solve this problem. In this study, we design a multi-purpose station and a multi-function device using a soft normally open point (SOP). A new multi-station integration topology and a coordinated control strategy are developed using an active power signal (APS) and an energy management system (EMS). The coordinated control strategy involves sending out the corresponding operation mode command after the EMS receives the superior instruction or the APS of the local system and coordinating the operation mode of the SOP, energy storage DC/DC converter, and photovoltaic DC/DC converter, thereby ensuring stable and efficient operation of the multi-station fusion system. Finally, two typical cases are simulated to verify the feasibility and effectiveness of the proposed topology and control strategy.

Data-Driven Adaptive Operation of Soft Open Points in Active Distribution Networks

The integration of soft open point (SOP) effectively improves the flexibility of active distribution networks (ADNs). However, in practical operation, accurate network parameters are difficult to obtain and the operation state changes rapidly with distributed generators (DGs). With the development of information technologies, massive operation data can be acquired in ADNs. How to utilize multisource data has become the key to realize the intelligent operation of ADNs. This article proposes a data-driven operation strategy of SOP based on model-free adaptive control (MFAC). First, considering the inaccurate parameters and frequent change of operation states, a data-driven framework is formulated for the real-time operation of SOP. Then, the operation strategies of multiple SOPs are further improved with interarea coordination. The results of case studies show that driven by the measurement data, the potential benefits of SOPs are explored to adaptively respond to system state changes and improve the operational performance of ADNs.

Experimental thermal hazard investigation on carbonate electrolytes using a cone calorimeter

During the thermal runaway (TR) processing of lithium-ion batteries (LIBs), electrolyte would release most of the heat as the main component. Thus, study on the fire risk of electrolyte is conductive to quantitatively evaluate the safety of LIBs. In this work, the combustion characteristics of three kinds of carbonate mixture electrolytes and the composition of residue were investigated. The significant parameters from the cone calorimeter tests reflecting the thermal hazards such as heat release rate (HRR), mass loss rate (MLR) and open cup flash point were measured. The HRR curves at the radiant power of 15 and 25 kW/m2 were more gradual than those at 35 kW/m2 which had one or two apparent peaks. The addition of diethyl carbonate (DEC) increased the HRRs significantly. The applicability of thermal chemistry (TC) theory used to calculate HRR in previous works was studied. The results of TC technique had a disparity with those from the cone calorimeter called oxygen consumption (OC) calorimetry especially for the electrolyte containing DEC, which was proved by thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) experimental results, while it is different from the conclusion reported in previous study. The constituent of carbonate electrolytes residue was analyzed by the X-ray Fluorescence (XRF). Element fluorine (F) accounted for over 90% of the residue. The open cup flash point and ignition temperature were determined by the open cup flash point apparatus. The results showed that the fire point was very close to the open cup flash point, and the difference was within 0.1 K.

Spatial accessibility and functional layout impacts on urban underground space development: a case study of Shanghai

Over the past decade, China’s megacities such as Shanghai and Beijing have witnessed great progress in their metro networks. With the rapid development of metro system, urban underground space (UUS) in China has been widely utilized in a systematic manner, following the principles of transit-oriented development. A comprehensive understanding of the impacts of the built environment on UUS is doubtlessly conducive to the high-quality and sustainable urban development. However, there are fewer researches conducted to study the impacts on UUS compared with those studies focusing on ground level space. Moreover, quantitative researches using multi-source big data on underground space are limited, which makes it hard to reveal the development regulation with high-precision at a large scale. This paper aims to study the impacts of spatial accessibility and functional layout on UUS. Shanghai, as one of the most prosperous megacities in China with well-developed underground space, was selected as the case study. In this paper, open data from Open Street Map and Point of Interest (POI) in AMAP was adopted. Indices such as integration (index of space syntax) of metro line, road length, road density, POI density, and entropy of POI were chosen to reflect the spatial accessibility and functional layout. Underground POI (UPOI) density was set as a proxy of UUS development intensity. A quantitative analysis using multiple linear regression model was conducted. The results showed that both two kinds of indices strongly correlated to the underground space development, whereas the influences of selected indices on UUS were different. At last, the characteristics of UUS in Shanghai and further development strategies were discussed, which provided a perspective of smart growth for planners, designers and authorities.

The Education System between Private Business and the State: The Antagonism and Synergies of Industrial and State Paternalism in the Vítkovice Company Town (1869–1914)

AbstractThis article aims at analyzing, within the scope of industrial and state paternalism, the interdependent dynamics between employer (Witkowitzer Bergbau- und Eisenhüttengewerkschaft), employee, and the Austro-Hungarian state, taking as an example the development of the education system of the Vítkovice (Witkowitz) company town, located in Moravia, one of the crown lands of the Habsburg Monarchy. The opening point of our research is the year 1869, when the so-called Hasner school law was adopted. The closing point is February 1914, with its new intervention into educational policy in the crown land of Moravia.

Analysis of Micro-Segregation of Solute Elements on the Central Cracking of Continuously Cast Bloom

On the basis of the Brody–Flemings model and modified Voller–Beckermann model, an analytical model of micro-segregation is established by considering the actual solidification cooling conditions of bloom. According to the developed model, the interdendritic solute distribution at the origin of the cracking gap is obtained. It is found that both phosphorus and sulfur have quite severe segregation, but both carbon and manganese have slight segregation; these results agree well with the semiquantitative analysis results of the scanning electron microscope (SEM). At the same time, the interdendritic segregation leads to an enhanced increase in the temperature range of crack formation; correspondingly, the possibility of cracking significantly increases and, thus, element segregation is the internal cause of crack formation. On the other hand, taking into account heat transfer, phase transformation, and metallurgical pressure, the strain of the solid shell is revealed through finite element software. When the solid shell thickness is equal to the distance of 90 mm between the opening point of the crack and the inner arc side, the tensile strain of the solid front is much bigger than the critical strain, which meets the external cause of crack formation; therefore, reasons for the cracking of blooms are successfully found.

The Optimal Placement and Sizing of Distributed Generation in an Active Distribution Network with Several Soft Open Points

A competent methodology based on the active power loss reduction for optimal placement and sizing of distributed generators (DGs) in an active distribution network (ADN) with several soft open points (SOPs) is proposed. A series of SOP combinations are explored to generate different network structures and they are utilized in the optimization framework to identify the possible solutions with minimum power loss under normal network conditions. Furthermore, a generalized methodology to optimize the size and the location of a predefined number of DGs with a predefined number of SOPs is presented. A case study on the modified IEEE 33 bus system with three DGs and five SOPs was conducted and hence the overall network power loss and the voltage improvement were examined. The findings reveal that the system loss of the passive network without SOPs and DGs is reduced by 79.5% using three DGs and five SOPs. In addition, this research work introduces a framework using the DG size and the impedance to the DG integration node, to propose a region where the DGs can be optimally integrated into an ADN that includes several SOPs.

Crashed Electric Vehicle Handling and Recommendations—State of the Art in Germany

In the near future, electric powered vehicles will represent a major part of the road traffic. Accordingly, there will be a natural increase of accidents involving electric vehicles. There are not many cases of such accidents yet and therefore the experience and correct handling are still partially open points for the involved parties, such as the rescue services for example. The aim of this work is to provide a complete overview of the accident handling sequence in Germany, starting with the damaged vehicle on site and moving on to the risks and challenges for the stakeholders, such as transport and recycling companies. Arising from the developed overview, a handling recommendation for yet undiscussed points is given. Especially, different extinguishing and deactivation methods are compared and discussed. Due to a lack of a common live-feed from battery data on site, other criteria have to be taken into account to assess the state of the battery. The wrecked vehicle—including the high voltage system—needs to be in a definite safe state at the handover to a towing service. Depending on the case, different options for securing the vehicle will be considered in this work.

Optimal planning of a soft open point in a distribution network subject to typhoons

While Soft Open Point (SOP) shows its strong capability to control load transfer and regulate network voltage profile in a distribution network, there are limited considerations of the high investment costs of these special electric devices. This gap may hinder optimal planning of an SOP and even affect its wide usage in a distribution network. This paper proposes an optimal planning method for an SOP that fully considers the cost of an SOP in a coastal network where typhoon frequently lands. The benefit of the SOP consists of the reduction of energy loss in daily operations and the post-fault supply restorations under extreme typhoon environment. The evaluation of the benefit of the SOP from the reduction of energy loss in daily operations is based on simulations of multiple scenarios in the long-term life cycle of the SOP. In order to evaluate the damages to the distribution network from typhoon, the virtual typhoon samples are generated from historical data in the entire period of the life cycle of the SOP. A practical algorithm is designed for the scanning of the possible formations of islands that can be restored by an SOP when typhoon lands. In the end of the paper, both the location and the capacity of an SOP are optimized considering the balance among the benefit of energy-loss reduction in daily operations, the benefit of supply restoration after typhoon lands, and the investment and operation costs of the SOP. From numerous simulations, it is validated that implementing only one SOP in the distribution network is both optimal and practical in most simulation cases due to the restrictions of the extremely high implement costs of SOP, and this may greatly simplify the complexity of the optimal planning problem for the SOP in a distribution network.

Minimization of Network Power Losses in the AC-DC Hybrid Distribution Network through Network Reconfiguration Using Soft Open Point

The Alternating Current-Direct Current (AC-DC) hybrid distribution network has received attention in recent years. Due to advancement in technologies such as the integration of renewable energy resources of DC–type output and usage of DC loads in the distribution network, the modern distribution system can meet the increasing energy demand with improved efficiency. In this paper, a new AC-DC hybrid distribution network architecture is analyzed that considers distributed energy resources (DER) in the network. A network reconfiguration scheme is proposed that uses the AC soft open point (AC-SOP) and the DC soft open point (DC-SOP) along with an SOP selection algorithm for minimizing the network power losses. Subsequently, the real-time data for DER and load/demand variation are considered for a day-a-head scenario for the verification of the effectiveness of the network reconfiguration scheme. The results show that the proposed network reconfiguration scheme using AC-SOP and DC-SOP can successfully minimize the network power losses by modifying the network configuration. Finally, the effectiveness of the proposed scheme in minimizing the network power losses by the upgraded network configuration is verified by constructing an AC-DC hybrid distribution network by combining two IEEE 33-bus distribution networks.

A multi-time scale energy management method for active distribution networks with multiple terminal soft open point

This paper proposed a multi-time scale robust energy management method for active distribution networks with the multiple terminal soft open point where the active distribution network and microgrids belonged to different ownerships. In the day-ahead Stackelberg game model, the time-of-use price and active power exchange plan between the active distribution network and microgrids were optimized under power flow constraints to balance economic benefits of all participants. Then a reactive power re-optimization model was established to minimize system voltage deviation under the tolerant cost constraint by utilizing residual capacity of voltage source converters. In the intraday model, considering the fluctuations of actual power exchange of microgrids, V2-P and V2-Q droop control mode was implemented in the soft open point, and a slope robust optimization model was established to improve system robust security within the uncertainty set. Case studies show that the proposed method can efficiently utilize the flexible power flow regulation capability of the multiple terminal soft open point, and improve both economic benefits and reliability of the system.

A novel distributed generation planning algorithm via graphically-based network reconfiguration and soft open points placement using Archimedes optimization algorithm

Hosting capacity (HC) is the mathematical interpretation for the maximum aggregated distributed generations (DGs) penetration among the distribution networks. DGs integration has been adopted as a cleaner energy resource, but it has major operational issues like overvoltage, harmonics, and others. In this work, a novel mathematical optimization algorithm is adopted for HC maximization via sequential network reconfiguration followed by soft open points (SOPs) placement. Besides, a novel SOPs allocation index is proposed to reduce the computational burden taken by the optimization techniques while controlling the discrete allocation variables. Thus, to ensure maximum penetration of DG units and optimum operation scheme, HC maximization is formulated as multi-objective optimization approach, while considering system performance indices as a portion of the objective function. The proposed optimization algorithm succeeded in maximizing the HC of the IEEE 33- node distribution network, the IEEE 69- node network, the 59-node Egyptian distribution network and the 135-node Brazilian distribution network efficiently while improving system performance indices. Further analysis is conducted on the studied distribution systems to assess the effect of load growth on system’s HC after allocating both SOPs and DGs.

Review and New Aspects in Combining Multipoint Moulding and Additive Manufacturing

Additive manufacturing has become a very important manufacturing method in the last years. With additive manufacturing, a higher level of function integration can be achieved compared to traditional manufacturing technologies. However, the manufacturing of larger parts leads to long construction times. A possible solution is the combination of multipoint moulding with additive manufactured form elements. This article reviews the state of technology for multipoint moulding and additive manufacturing. Moreover, the state of technology is analysed to outline the possibilities and challenges of combining both technologies. The review shows that there has been research on different challenges of the new production process. On the other hand, it turns out clearly that there are many open points at the intersections of both technologies. Finally, the areas where further research is necessary are described in detail.

Experimental study on particulate control of turbo gasoline engine

This study takes light-passenger vehicles with 1.5L port fuel injection turbocharged engine as the research object, based on the WLTC test cycle about the China 6b emissions regulations, including some influence of several key technologies, such as fuel injector selection, intake VVT opening, fuel control and gear shift point matching, what can affect the particulate emissions from light-passenger vehicles. The results show that without particulate filter (GPF) technology, Using the original 4-hole fuel injector, the opened intake air VVT in catalyst light off, the optimized fuel control and gearbox shift point, the emission test results of the light-passenger vehicle can reach the development target of China 6b, what can avoid GPF blockage and regeneration problems in the market. Meanwhile, the cost of mass production and development cycle about vehicle is effectively reduced.

Detection of Open Conductor Fault Using Multiple Measurement Factors of Feeder RTUs in Power Distribution Networks With DGs

Open conductor faults are causing socioeconomic problems worldwide owing to fires caused by arc generation and increased risk of human electric shock. Also, the recent increase in the interconnection of distributed generators (DGs) has further aggravated the difficulty in detecting open conductor faults. In this study, we proposed a detection method for open conductor faults in power distribution networks using multivariate measurement factors of feeder remote terminal units (RTUs). The proposed method has the following advantages over the existing methods. First, the applicability in actual networks has been secured by utilizing the measurement values detectable in a general RTU. We analyzed the characteristics of open conductor faults according to the fault type, transformer connection, DG, etc., which we devised detection procedures for RTUs at the source-side and load-side of the open conductor point and developed an algorithm for open conductor detection. Using the proposed detection method, each RTU derived three results of open conductor alarm, warning, and no detection. Second, the detection problem caused by the DG in the existing open conductor method was rectified. Also, the limitations of classification between open conductor fault and other events were improved. Simulations using Matlab Simulink for a standardized power distribution network proved that the proposed method has a higher open conductor detection rate and distinguishing capability compared to the existing methods. Lastly, we demonstrated the applicability of the proposed method to a real system by deriving the optimal detection criteria using a sensitivity analysis.

The New Three Lines Model for Structuring Corporate Governance – A Critical Discussion of Similarities and Differences

The efficient and effective organization and coordination of corporate governance activities is still one of the major challenges of modern corporate management. For many years, it was precisely the so-called Three Lines of Defense model that was used to structure governance functions. However, as more and more open points of discussion regarding practical implementation have emerged over the past years, the Three-Lines model was published in 2020 as a fundamental update by the Institute of Internal Auditors. This article critically presents the new model and discusses the similarities and differences to the existing model. Thus, this article contributes to the current discussion of best practices in corporate governance structure and the fundamental issues of an efficient and effective oversight. Both, practitioners and researchers should benefit from the critical discussion.

The new three lines model for structuring corporate governance – A critical discussion of similarities and differences

The efficient and effective organization and coordination of corporate governance activities is still one of the major challenges of modern corporate management. For many years, it was precisely the so-called three lines of defense model that was used to structure governance functions. However, as more and more open points of discussion regarding practical implementation have emerged over the past years, the three lines model was published in 2020 as a fundamental update by the Institute of Internal Auditors (IIA). This article presents the new model and critically discusses the similarities and differences to the existing model. Thus, this article contributes to the current discussion of best practices regarding corporate governance structure and the fundamental issues of efficient and effective oversight. Both practitioners and researchers should benefit from the critical analysis of this paper.

Control strategy for DC soft open point in large scale distribution networks with distributed generators

Development of power electronic devices and their implementation in power distribution networks significantly improve not only the easier integration of distributed generation into distribution networks but also the further refinement of control algorithms specialized in the application of power management procedures in distribution systems. Implementation of DC Soft Open Points (DCSOP) for closing loops in distribution networks could serve as one of the most representative examples of the use of power electronics devices as a management resources in modern distribution networks. The paper describes the possibilities of application of DCSOP used for loops closure and power flow control in medium voltage distribution networks with integrated distributed generators. Considering all benefits of loops closure and the controllability of the DCSOP, DCSOP has been considered as a management resource capable of achieving the desired/optimal state in the distribution network. The management strategy proposed in this paper covers two cases: the first case where adequate communication infrastructure is available when all DCSOP operation is based on Optimal Power Flow (OPF) calculations, and the second case when OPF results are unavailable for some reason (most often due to communication interruptions) and DCSOP operation is based on processing available data using neural network based algorithm. The proposed management strategy has been implemented and tested on the IEEE 33 distribution test network with integrated distributed generators. The simulation results, described in this paper, can serve not only as a basis for further scientific research but also as a basis for the practical implementation of real controllers based on the proposed algorithm and its application in practice, in real distribution networks.

Optimal Planning of Active Distribution Network Based on Soft Open Point and Shunt Capacitors

As the penetration of distributed wind power in the distribution network continues to increase, the uncertainty of its output has a serious impact on the stable operation of the distribution network. It is difficult to meet the voltage regulation requirements when the wind power fluctuates frequently only by relying on shunt capacitors. Therefore, a coordinated optimization planning method based on soft open point (SOP) and shunt capacitors is proposed. Firstly, the bidirectional generative adversarial network (BIGAN) is used to characterize the uncertainty of wind power output and generate typical scenarios of wind power output. Secondly, a multi-objective optimization planning model of SOP and shunt capacitors is proposed based on the scene analysis method; Then, a solution strategy based on the improved elitist non-dominated sorting genetic algorithm (NSGA-II) is proposed. Finally, the proposed planning model and solution are verified and analyzed in the improved IEEE 33-bus system.

An Extended Control Strategy for Weakly Meshed Distribution Networks With Soft Open Points and Distributed Generation

As part of the smart grid concept, different strategies specialized for power flow control in distribution networks have been developed. One of the possible solutions to optimize the utilization of existing capacities and increase distributed generation penetration is the implementation of Soft Open Points. Soft Open Points are modular devices based on power electronic converters that enable closing loops in the network without negative consequences regarding fault current propagation. Introducing the concept of soft open points in the distribution network enables power flow control in a particular part of the network and voltage control in the soft open point connecting nodes. The control strategy proposed in this paper addresses the main obstacle for appropriate exploitation of soft open points, defining reference values for control variables in the case of large-scale distribution systems. Furthermore, the proposed strategy also deals with data unavailability problems, that is, soft open point control under communication interruption. The proposed control algorithm incorporates centralized optimal power flow calculations and an estimation algorithm based on a multivariate polynomial regression. The optimal power flow is used to calculate the control variables in normal operation modes. The procedure based on multivariate polynomial regression was used to estimate the reference values of the control variables when the optimal power flow results were unavailable. This feature makes the proposed algorithm applicable to communication interruptions when only limited data capture is available. The algorithm proposed in this study was implemented and tested on a test network considering different scenarios. Conclusions and simulation results make this algorithm applicable to an actual soft open point controller.