Substation Structures Research Articles

Modeling of Reaction Forces in High-Voltage Substation Structures

When designing utility substations, it is necessary to consider all directional components of the electromagnetic reaction forces during short-circuit faults to properly account for their effects on substation equipment. IEEE 605 assumes straight long parallel conductors in its two-dimensional (2-D) force calculations while ignoring any bends and 3-D placement of conductors. CIGRE's Brochure 105 provides practical information on the mechanical effects of short-circuit currents in HV and EHV open air, conventional substations. Although these computational methods are easy to implement, they have several limitations and are sometimes too conservative. Previously published papers address such conservatism using dynamic analysis approaches that provide more accurate results when compared to experimental data. This paper provides two extensions to IEEE 605 and CIGRE 105 for calculating fault current reaction forces. A closed-form equation defining the simplified 2-D short-circuit force time history during a fault based on CIGRE 105 and a computationally inexpensive numerical 3-D force calculation technique are presented.

Research on the Application of Fabricated Steel Structures to the 220kV Indoor Substations

The significant development of fabricated steel structure is helpful to solve the issue of excessive productivity in steel industry and promote the greenization, informatization and industrialization in construction industry. This paper takes a 220kV indoor substation for example to compare the stress ratio, displacement, types of joints and steel quantity of the steel pipe column frame with those of the mixed one. The result demonstrates that the employment of steel pipe columns for indoor substation structures can generate certain economic and social benefits.

Digital combined instrument transformer for automated electric power supply control systems of mining companies

The present paper discusses ways to solve the problem of enhancing operating efficiency of automated electric power supply control systems of mining companies. According to the authors, one of the ways to solve this problem is intellectualization of the electric power supply control system equipment. To enhance efficiency of electric power supply control and electricity metering, it is proposed to use specially designed digital combined instrument current and voltage transformers. This equipment conforms to IEC 61850 international standard and is adapted for integration into the digital substation structure. Tests were performed to check conformity of an experimental prototype of the digital combined instrument current and voltage transformer with IEC 61850 standard. The test results have shown that the considered equipment meets the requirements of the standard.

Assessment Method for Substation Capacity Credit of Generalized Power Source Considering Grid Structure

This paper presents the concept of the generalized power source in an active distribution network. After the energy storage system (ESS), distributed generators (DG), and demand-side controllable load are connected to the active distribution network, part of the system load can be undertaken by these ESS, DG, and controllable load instead of relying on the capacity of the substation, which greatly improves the reliability of the system. The above-mentioned distributed energy resources in the active distribution network are collectively referred to as the generalized power source (GPS). Substation credible capacity refers to the capacity of the GPS to supply the distribution network that is equivalent at the high voltage distribution network level when considering the faults of the main transformer, 110 kV lines, and circuit breakers. Considering the uncertainties and control strategies of GPS, this paper takes a specific distribution area as the background to study its substituted substation capacity. Based on a sequential Monte Carlo evaluation framework and the principle of constant reliability, an evaluation method of the GPS credible capacity is proposed. In order to verify the effectiveness of the method proposed in this paper, the credible capacity of various typical connection modes of a high voltage distribution network is quantitatively analyzed in the case study, which can provide a reference for the capacity planning of an active distribution network substation and grid structure selection.

Simulation Analysis of Strength of Double Layer Structure of Prefabricated Substation

The construction of the substation in the urban center has become a common phenomenon. There is a need to consider the cost of land, and make the substation covering a small area, safe and economical. This paper presents a new model of substation built with assembled upper and lower double layer structure of module blocks in the urban center, and proposes to install 110kV of prefabricated cabin on the top of 10kV and 35kV of prefabricated cabin, with a small area and easy construction, but the strength of double layer structure becomes the key to design. Based on the finite element theory, this paper establishes a finite element model of double layer structure of prefabricated substation in the finite element software ABAQUS, and carries out strength simulation analysis of the most unfavorable conditions, of which the inclined degree of the entire structure is 5°, and the seismic intensity is 8°. The research results show that: when the inclined degree of the entire structure is 5°, the maximum stress of the structure is 92.49MPa, and the safety factor of strength is 2.5; when the seismic intensity is 8°, the horizontal load excitation has a greater impact on the double layer structure, the maximum stress is 160.5MPa, and the safety factor is 1.5; the vertical load excitation has a less impact, and the maximum stress is only 30.3MPa. In the early period of design of the strength simulation analysis method, this paper can obtain the safety factor of strength of structure under the most unfavorable conditions, which has reference significance on the design and optimization of the structure of substation.

A Programme to Solution the Problem of OPGW Substation Structure Grounding

OPGW with functions of lighting proof and communication is widely used in the construction of power network. For optical fiber composite overhead ground wire (OPGW), it is required to achieve the separation of wire and signal after the introduction of the substation structure[1]; at the same time, the grounding for lightning proof is also required because of the frequent occurrence of the burnout of the optical cable and short circuit due to the electric discharge and lighting as a result of the problems in the grounding device or construction. This paper analysis some common advantages and disadvantages of OPGW structure grounding methods. In combination with the practical conditions of the project, the solution “Enhanced the grounding method” is brought up and solve the practical problem.

Ultrametricity of optimal transport substates for multiple interacting paths over a square lattice network.

We model a set of point-to-point transports on a network as a system of polydisperse interacting self-avoiding walks (SAWs) over a finite square lattice. The ends of each SAW may be located both at random, uniformly distributed, positions or with one end fixed at a lattice corner. The total energy of the system is computed as the sum over all SAWs, which may represent either the time needed to complete the transport over the network, or the resources needed to build the networking infrastructure. We focus especially on the second aspect by assigning a concave cost function to each site to encourage path overlap. A simulated annealing optimization, based on a modified Berg-Foerster-Aragao de Carvalho-Caracciolo-Froehlich (BFACF) algorithm developed for polymers, is used to probe the complex conformational substate structure at zero temperature. We characterize the average cost gains (and path-length variations) for increasing polymer density with respect to a Dijkstra routing and find a nonmonotonic behavior as recently found for random networks. We observe the emergence of ergodicity breaking and of nontrivial overlap distributions among replicas when switching from a convex to a concave cost function (e.g., x^{γ}, where x represents the node overlap). Finally, we show that the space of ground states for γ<1 is compatible with an ultrametric structure, as seen in many complex systems such as some spin glasses.

Culture adaptation alters transcriptional hierarchies among single human embryonic stem cells reflecting altered patterns of differentiation.

We have used single cell transcriptome analysis to re-examine the substates of early passage, karyotypically Normal, and late passage, karyotypically Abnormal (‘Culture Adapted’) human embryonic stem cells characterized by differential expression of the cell surface marker antigen, SSEA3. The results confirmed that culture adaptation is associated with alterations to the dynamics of the SSEA3(+) and SSEA3(-) substates of these cells, with SSEA3(-) Adapted cells remaining within the stem cell compartment whereas the SSEA3(-) Normal cells appear to have differentiated. However, the single cell data reveal that these substates are characterized by further heterogeneity that changes on culture adaptation. Notably the Adapted population includes cells with a transcriptome substate suggestive of a shift to a more naïve-like phenotype in contrast to the cells of the Normal population. Further, a subset of the Normal SSEA3(+) cells expresses genes typical of endoderm differentiation, despite also expressing the undifferentiated stem cell genes, POU5F1 (OCT4) and NANOG, whereas such apparently lineage-primed cells are absent from the Adapted population. These results suggest that the selective growth advantage gained by genetically variant, culture adapted human embryonic stem cells may derive in part from a changed substate structure that influences their propensity for differentiation.

Substation Design Optimization Research Based on PSO and Value Index Method

In this paper, an combined evaluation process to evaluate the value of substation was proposed. Firstly, a substation function index system was established with consideration of the function structure and features of substation. Secondly, the Analytic Hierarchy Process (AHP) and entropy method were separately used to calculate the subjective and objective weights of the function indexes. Thirdly, the sum of squares of deviations method and Particle Swarm Optimization (PSO) method were used to get the function indexes’ combined weights. At last, the evaluation model was formed by function index compared with the cost index. The substation design data were used to test the evaluation model, the results showed it was feasible.

Phosphorescence lifetimes of organic light-emitting diodes from two-component time-dependent density functional theory.

"Spin-forbidden" transitions are calculated for an eight-membered set of iridium-containing candidate molecules for organic light-emitting diodes (OLEDs) using two-component time-dependent density functional theory. Phosphorescence lifetimes (obtained from averaging over relevant excitations) are compared to experimental data. Assessment of parameters like non-distorted and distorted geometric structures, density functionals, relativistic Hamiltonians, and basis sets was done by a thorough study for Ir(ppy)3 focussing not only on averaged phosphorescence lifetimes, but also on the agreement of the triplet substate structure with experimental data. The most favorable methods were applied to an eight-membered test set of OLED candidate molecules; Boltzmann-averaged phosphorescence lifetimes were investigated concerning the convergence with the number of excited states and the changes when including solvent effects. Finally, a simple model for sorting out molecules with long averaged phosphorescence lifetimes is developed by visual inspection of computationally easily achievable one-component frontier orbitals.

Shared-network scheme of SMV and GOOSE in smart substation

The network structure of the smart substation in common use was introduced, and the technical problems of the shared-network of sampled measured value (SMV) and generic object oriented substation event (GOOSE) were analyzed, such as the processing ability of network device and the intelligent device, the data real-time property and the network reliability, the effects to the substation in the condition of network fault, etc. On this basis, the feasibility of the shared-network of SMV and GOOSE was discussed, the implement scheme was presented, and eventually the solution of the shared-network of SMV and GOOSE was put forward, which based on the applications of the message priority control, restricting the switch number, virtual local area network (VLAN) and GARP multicast registration protocol (GMRP) classification flow control, flow rate limiting, etc. In the test-bed, the cases of shared-network and separate-network of SMV and GOOSE were compared and analyzed, and the result was valuable for reference.

Research on the Shared-network of SMV and GOOSE in Smart Substation

The network structure of the smart substation in common use was introduced, and the technical problem of the shared-network of sampled measured value (SMV) and generic object oriented substation event (GOOSE) was analyzed, such as the processing ability of network device and the intelligent device, the data real-time property and the network reliability, the effects to the substation in the condition of network fault, and so on. On this basis, the feasibility of the shared-network of SMV and GOOSE was discussed, the implement scheme were presented, and eventually came to the solution of the shared-network of SMV and GOOSE, which based on the applications of the message priority control, restricting the switch number, virtual local area network (VLAN) and GARP multicast registration protocol (GMRP) classification flow control, etc. In the test-bed, the cases of shared-network and separate-network of SMV and GOOSE were compared and analyzed, and the result was valuable for reference.

A New Smart Substation Structure with Single Net and Single Equipment

a new generation of single equipment and single network structure of intelligent substation is proposed in this paper on the basis of the current three layers two network smart substation, the key technology of this kind of new intelligent substation needs are also proposed in this paper, such as port mirroring, VLANs and IEEE1588. Examples of key technologies are presented,using industrial Ethernet switch, providing reference for engineering applications of new smart substation .

An improvement to seismic design of substation support structures

The acceleration that the electrical equipment experiences on a structure can be several times the ground acceleration. Currently, substation support structures are being designed according to ASCE (Substation Structure Design Guide 2008), without any consideration about effects of these structures on dynamic behavior of mounted equipment. In this paper, a parametric study is implemented in order to improve seismic design of candlestick substation structures based on this design guide. To do this, dynamic amplification factor (DAF) of different candlestick support-equipment combinations is evaluated and compared to the target DAF presented in IEEE STD 693 (2006). Based on this procedure, a new criterion is developed to restrict maximum acceleration at support-equipment intersection.

Dynamic properties of substation support structures

Substation electrical equipment is usually mounted on different kinds of structures, which can have a very significant effect on the motion that the supported equipment will experience during an earthquake. In this paper, a parametric study is implemented in order to assess dynamic properties of substation support structures.In the first phase of this study, a simplified Four Degrees-of-Freedom (4-DOF) system is proposed in order to model different support-equipment systems and is verified through finite element method (FEM). Based on the proposed model, a practical equation is proposed to calculate the fundamental natural frequency of support-equipment systems and compared to the one proposed by ASCE (substation structure design guide, 2008). Furthermore, dynamic amplification factor (DAF) of substation support structures is calculated, and effect of different parameters (e.g. support mass, height and stiffness) is discussed. Finally, a new criterion is developed to restrict maximum acceleration at support-equipment intersection.Results of this paper can be utilized in order to design more proper support structures to preserve substation electrical equipment from seismic induced damages.

Switching Transient of 1000-kV UHV System Considering Detailed Substation Structure

The insulation level of power apparatus is mainly determined by the amplitudes and waveforms of system overvoltages. The substation is handled as a lumped equivalent model, and the detailed substation structure is not taken into account in present switching transient calculations. In this study, the influence of considering a substation structure on the switching transient calculation of a 1000-kV ultra-high-voltage system is analyzed, and the factors affecting this calculation are obtained. Generally, considering the substation structure will not affect the calculation of switching overvoltage amplitudes, but it will generate a damped oscillation with a very sharp wavefront and very high frequencies upon the familiar switching transient waveform. Attention should be paid to the insulation withstand level of air gaps and power apparatus to this kind of complex wave of a short-front rapid impulse superimposed on a long-front slow impulse.

IEC 61850 자동화 변전소에 SCL 기반 HMI 개발방법 연구

In this paper, a substation HMI based on IEC 61850 is proposed that uses SCL to have all information in substation to include standard concept of IEC 61850. A proposed substation HMI using SCL based on IEC 61850 expresses different display by each substation structure and component device change in substation. A proposed substation HMI is designed by IEC 61850 standard, and it suits for future substation HMI based on IEC 61850. A proposed HMI is proved by a program that is made by Visual C++ to use SCL file based on XML.

THE MINIMALIZATION OF FILTER EQUIPMENT FOR TRACTION SUBSTATIONS USING BOOSTER CONVERTER

The structure of traction substation 3,2 kV DC power source is considered. It is shown that the output filter choke of traction substation with voltage added converter may be excluded. A dynamic model of voltage added converter is developed, its features, as an active filter, are described.

Study on the bolting top-joint of substation truss–column

A new type of bolting top-joint of the substation truss–column was put forward and investigated in this paper. The top-joint is composed of one cover plate and two built-up tubes connected with high-strength bolts. The members of the bolting top-joint are much smaller than the common welding top-joint, the members are more convenient for fabrication, transportation and installation and the zinc process is much easier and cheaper. Firstly, as the dimensions and design loads of the welding truss–column in a 500 kV substation is concerned, the mechanic characteristics of 28 m long truss–columns including three bolting columns and one welding column were investigated numerically using finite element method. The results show that the mechanic characteristics of the proposed bolting truss–columns are comparative with those of the traditional welding truss–column. Then, the experimental model of bolting top-joint with 1:1 scale was built and the mechanic characteristics were studied experimentally. It was obtained from the numerical and experimental results that both the stiffness and the intensity of the proposed bolting top-joint depend on the thickness of the vertical plate as well as the number of bolt connections in the cover plate, and the bolting truss–column with this new kind of bolting top-joint could be used in substation structures instead of the common welding truss–column.

Ionic Current Blockades from DNA and RNA Molecules in the α-Hemolysin Nanopore

We characterize the substate structure of current blockades produced when single-stranded polynucleotide molecules were electrophoretically driven into the α-hemolysin protein pore. We frequently observe substates where the ionic current is reduced by ∼50%. Most of these substates can be associated with a molecular configuration where a polymer occupies only the vestibule region of the pore, though a few appear related to a polymer occupying only the transmembrane β-barrel region of the pore. The duration of the vestibule configuration depends on polymer composition and on which end of the polymer, 3′ or 5′, subsequently threads into the narrowest constriction and initiates translocation. Below ∼140 mV a polymer is more likely to escape from the vestibule against the applied voltage gradient, while at higher voltages a polymer is more likely to follow the voltage gradient by threading through the narrowest constriction and translocating through the pore. Increasing the applied voltage also increases the duration of the vestibule configuration. A semiquantitative model of these trends suggests that escape has stronger voltage dependence than threading, and that threading is sensitive to polymer orientation while escape is not. These results emphasize the utility of α-hemolysin as a model system to study biologically relevant physical and chemical processes at the single-molecule level.