Main Substation Research Articles

Analysis of the number of switches of on-load tap changer of a power transformer for field substation, taking into account discrete time and voltage level sampling

The introduction of “smart grids” technologies poses the problems of multi-criteria determination of the optimum voltage in the main substation of the object under study. In this study the busbar sections of the field substation of the oil and gas company is considered as the main substation. This paper studies regulation of voltage level in an electrical network using on-load tap changer (OLTC) of a power transformer for field substation of an oil and gas enterprise. Considered are approaches for voltage regulation taking into account the development of smart grid technologies. The authors have developed a universal method for determining the optimal voltage level on the busbar sections of a field substation, which allows for selection of the optimum voltage in accordance with certain parameters: loss of active, reactive power, voltage, electricity consumption, specific consumption or efficiency factor of artificial oil lift. The actual daily graphs of consumption of active, reactive power and voltage level at one of the field substations of PJSC Tatneft were studied. The operation mode of on-load tap-changer drive of the field transformer was modeled, taking into account the calculated optimal values of voltage and the dead zone. The paper presents the results of study of automatic voltage regulation on busbar sections of a field substation, taking into account the constraints for tap changer switches of a power transformer.

The influence of switching actions with redundant components on the main reliability substations

In this paper is presented a substations reliability analysis based upon substation’s component outage or failure modes. The switching actions can be modelled in the reliability evaluation indices we used the three-state model of the substation components (for example circuit breaker). The reliability indices are evaluated using the minimal cut-set method for each components of substation.

A Wideband Single End Fault Location Scheme for Active Untransposed Distribution Systems

This paper presents a single end fault location scheme for distribution networks with distributed generation (DG). The high frequency transients generated when a fault occurs are used to locate the fault point. An equivalent circuit at high frequencies is derived for both inverter based and synchronous DGs. The voltages and currents measured only at the main substation are used in conjunction with the proposed DG model to create the fault location scheme. The distributed parameter line model is employed in the derivation to account for the line characteristics, e.g., inductive and capacitive mutual coupling and untransposed lines. The inverter based DG model is validated experimentally on a 400 V, three-phase system. The IEEE 34-bus feeder is simulated and used to evaluate the proposed scheme for different operating conditions, e.g., fault resistance and DG conditions. The extensive simulation studies show the accuracy of the proposed scheme with 95.3% of the test cases having an absolute error in estimation of less than 200 m.

Placement of photovoltaic and capacitors in the 20 kV Jeneponto Distribution Network

Indonesia is located on the equator which has a good intensity of solar radiation throughout the year. This radiation condition gives the potential for photovoltaic placement in Indonesia. Jeneponto Regency is one of the areas in South Sulawesi that has the high potential for the construction of photovoltaic (PV) with irradiation levels reaching 5.404 kWh/m2/day. This research aims to determine the location of photovoltaic and capacitor interconnection points in the 20 kV Jeneponto distribution system for optimizing voltage stability and minimizing power losses. The optimal simulation of the determination of interconnection points is carried out by simulating photovoltaic placement in different main buses, which are Jeneponto main distribution substation, Jeneponto switching substation, Tolo switching substation and Benteng switching substation. The results analysis showed that the photovoltaic interconnection point in Benteng switching substation produces the smallest power losses and all loads have a voltage profile that complies with both IEEE and PLN voltage standards.

Cloud-Fog-based approach for Smart Grid monitoring

Continual, safe, secure, reliable, and efficient delivery of high-quality power is the main goal of the Smart Grid (SG) defined as the energy network integrated with the novel Information and Communication Technologies (ICTs). This paper focuses on the development of communication system models to be used for voltage profile monitoring and power losses estimation in SG. Existing research on communication technologies in SG is briefly overviewed with the main focus on Cloud and Fog computing approaches. With rising numbers of smart devices in SG, the amount of measurement data rapidly increases demanding more efficient communication architectures. Two communication architectures are selected and modeled with the main goal to support real-time monitoring and data analysis in SG. Cloud- and Cloud-Fog-based approaches are proposed and analyzed as communication system models for SG real-time monitoring. Posting immense quantities of data on Cloud commonly represents a serious challenge due to latency, locality, and network congestion. The best approach to overcome Cloud challenges is to perform decentralized and intelligent processing closer to the location where data are being generated, which is known as Fog computing. A MATLAB/Simulink-based model of a well-known IEEE test grid topology is modified to support real-time communication with open source IoT platform ThingSpeak used for Cloud computing. Fog computing layer is conceptualized to be located in the main distribution substation and it is modeled by MATLAB function blocks. The proposed modeling procedure is given step by step to highlight the most important building blocks necessary for creating a combined power and communication system model capable of providing meaningful data related to SG monitoring. The developed model is tested using simulation events common in distribution networks. The simulation results of Cloud and Cloud-Fog approaches for voltage profile monitoring and power losses calculation in SG have confirmed the benefits of the Cloud-Fog-based approach.

A Communication-assisted Scheme in Radial Distribution Systems Using Phasor Measurement Units

Automation of the distribution system may be an essential requirement in the smart grid architecture. In this paper, the architecture of the distribution system has been proposed, where Phasor Measurement Unit (PMU) has been placed at the main substation receiving supply from the grid through the incoming feeder, as well as at all distribution transformers (DTs). PMU installed at the main substation is linked to master controller through IEC 61850. PMUs placed at DTs are connected to the corresponding local controller through the IEC 61850. Estimated voltage and current phasors together with frequency are transmitted from PMU to the local controller through IEC 61850 communication protocol. Controllers perform different tasks based on the data received from PMUs. Each local controller is linked to master controller as well as to all smart meters placed at loads supplied by the DT. Bidirectional exchange of information takes place between master and local controllers as well as between local controller and smart meter. PMUs are also linked with the smart meters using PLC communication link. In this paper, information about the available power at the substation and at the distribution transformer is developed in real-time with the help of PMU by considering the load disconnection/connection based on available power (from time t = 0.56sec to time t = 0.75sec), protection of feeder against overcurrent (from time t = 0.15sec to time t = 0.20sec), and power theft detection and elimination (from time t = 0.21sec to time t = 0.23sec) through eMEGASim® OP5600 OPAL-RT real-time simulator.

Substation Monitoring and Control using Rs485 Transceiver

Through this project, prioritization of distribution of two power stations by monitoring and detecting the power imbalance at the earliest and reversing the data’s so it can be rectified. RS485 is utilized as the solid layer underlying several routine protocols employed to execute industrial control systems. This system is programmed to also convey the real time electrical parameters recurrently and thus enable the main substation to monitor the parameters. This main station apparatus is developed to cut off subsequent substation power whenever the voltage or current exceeds the predefined limits.

STUDI TRANSFORMATOR PADA GARDU INDUK PANAKKUKANG PERUSAHAAN LISTRIK NEGARA WILAYAH III

The operation failure of one of the main substation equipment, resulting in a number of end-users of electricity will be impaired. Maintenance on major equipment substation needs to be done to prevent damage and disruption as early as possible, and can extend the life of the equipment. Thus, the system of maintenance of equipment at a substation needs to be maintained and improved, especially on equipment - equipment that is essential for channel function and securing of a power interruption.

GA-based optimization for optimally placed and properly coordinated control of distributed generations and Static Var Compensator in distribution networks

This paper presents the impact assessment of distributed generations (DGs) (such as T2 and T4 i.e operating at different power factors such as 0.85, 0.90, 0.95 and 0.99 leading and lagging, respectively) and flexible alternating current transmission systems (FACTS) controllers like SVC with different load models (DLMs) in distribution power system networks by using genetic algorithms (GA) from minimum total MVA intake of main substation viewpoint. The different type DGs (such as T2 and T4 i.e. operating at different power factors such as 0.85, 0.90, 0.95 and 0.99 leading and lagging, respectively) and FACTS controller like SVC with DLMs are considered by employing GA in DPSs form minimum total MVA intake of main substation viewpoint. Different distribution power system (DPS) performance indices viewpoint, such as minimization of real power loss, minimization of reactive power loss, improvement of voltage profile, reduce the short circuit current or MVA line capacity and reduce the environmental greenhouse gases like carbon dioxide (CO2), sulfur dioxide (SO2), nitrogen oxide (NOx) and particulate matters in an emergency e.g. under fault, sudden change in field excitation of alternators or load increase in DPSs are considered. This paper also investigated the comparisons of different DGs (such as T2 and T4) and FACTS controller like SVC with DLMs by employing GA in DPSs form minimum total MVA intake of main substation viewpoint. The effectiveness of the proposed methodology is tested on IEEE 37-bus distribution test system. All the simulations are done on MATLAB package toolbox.

Insulation failure caused by special pollution around industrial environments

In the recently years, the industrial process has increased his production, in this way, the energy consumption has grown significantly with more substations and overhead lines around the industrial plants with lime production. There are many challenges in this kind of industry. One of the main polluting agents is the lime, in a Gold concentrator plant for power substation. The lime is composed primarily of hydroxide, oxides, and their composed. The porcelain is usually used for the insulation between the electrical devices as the circuit breaker, Insulators, current transformers, surge arresters, among others. The insulation has some changes with the climatic change and his manifestation as the moisture, fog, rain and snow. Although the electrical engineering has important advances, about the insulation and maintenance, the insulation failure caused by lime pollution and fog condition has an important relevance, associated to the partial and corona discharge, this condition has been found in the insulation associated to the bus bar Insulators. The main characteristic is the influence of lime and fog, in an area of heavy pollution with high voltage substations. In this research, the partial and corona discharges are described in the section 2, with the electronic devices for the diagnosis and the description of the components for the failure in the insulation, besides, in the section 3 is described the case study with the largest Industrial process in Chile associated to the main substation in 220 kV. In addition, the section 4 has the results and discussion about this phenomenon with the alternatives for assessment and corrections in this environment, accordingly, the results of this research should make available a reference to improve the efficiency of the maintenance and fault diagnosis.

Tokamak T-15MD—Two years before the physical start-up

At the present time, in the NRC Kurchatov Institute under the auspices of the Federal Target Program “Nuclear energy-technologies of new generation for period 2010–2015 and to the prospect until 2020” the tokamak T-15MD and supporting facilities are being built. The preassembly of the tokamak T-15MD magnet system together with the vacuum vessel was completed at a plant in Bryansk. All elements of the magnet system and vacuum vessel have been delivered to the NRC “Kurchatov Institute” in Moscow for the tokamak T-15MD assembly. It is expected that the T-15MD assembly will be completed in March of 2019. The reconstruction of the sub-station 110/10/04 kV for own needs was completed in 2017 and the reconstruction of the main sub-station 110/10/1 kV, 300 MW was completed in 2018. Twenty- two of the new transformers 10/1 kV and 20 new thyristor convertors will be installed during 2018–2019 period. One gyrotron with output power 1 MW for pre-ionization should be installed in 2019. Tokamak T-15MD connection to water and electrical communication and also the adjustment of control system will be completed in the middle of 2020. Physical start-up T-15MD is scheduled for December 2020 year.

CHARACTERISTIC LAYOUTS OF DISTRIBUTION NETWORKS WITH THE ANALYSIS OF VOLTAGE DEVIATIONS AND EXPEDIENCY OF ITS CONTROL

Urgency of the research. It is well-known that electric energy characteristics are the levels of electromagnetic compatibility of electric grid providing adequate performance of any electrical means connected to the grid if the electric energy characteristics do not exceed permitted values. In the context of general idea of electromagnetic compatibility of consumers within power supply grids, power quality is the topical problem of modern electric-power supply industry. Target setting. The issue of assessing the possibility of ensuring the quality of electricity in terms of voltage deviation by consumers is very important. The problem of voltage fluctuations is relevant, so that voltage deviation have a negative impact on functioning electrical equipment Actual scientific researches and issues analysis. Papers [2-11] are devouted the effective management methods of electrical energy consumption. The articles [6-8] shows that under present conditions only system approach ensures accurate identification and prediction of electric power losses in distribution networks that are characterized by considerable ambiguity. Uninvestigated parts of general matters defining. Generalized diagram of the voltage modes characterizes the state for the entire distribution network connected to the main substation; it consists of the branched 10 kV network, all the distribution transformers, and all the 0.4 kV networks connected to those transformers. Along with the generalized diagram, values of the available voltage losses have been obtained; those values occur within 10 kV and 0.4 kV networks in terms of the favourable conditions of voltage control and the initial values of the admissible voltage deviations of electrical receivers. Moreover, that is the basis to determine operating position of control tappings of distribution transformers. The research objective. Since one of the important characteristics of electrical energy is the deviation of the voltage in the network, it is advisable to carry out its analysis in the urban distribution networks in terms of Levanevska substation, town of Zaporizhzhia. To simplify practical representation of possible voltage modes on the main substation buses and within the whole distribution networks, it is expedient to use graphic representation – so-called generalized diagram of voltage modes. That diagram helps make the analysis of voltage modes more demonstrative than analytical calculation; besides, the diagram gives great possibilities for further study. The statement of basic materials. While analyzing voltage mode in the distribution networks and determining the required law of voltage control in the main substation (MS), one should take into consideration great amount of factors effecting and complicating that study. Those factors include the following: changes in the operating mode of the network, differences in the points of connections of electrical receivers (ER) to the distribution network, differences in possible operating positions of the control tappings in the distribution transformers (DT), differences in the points of DT connections to 10 kV network, available dead zones of automatic voltage controller etc. Owing to that fact, it is required to perform generalized analysis of the voltage mode and conditions of its control within 10 kV and 0.4 kV distribution networks and on main substation buses. To do that, one should apply probabilistic calculation methods. At the same time, it is expedient to use graphic depiction (so-called generalized diagram (GD) of the voltage modes) to simplify representation of possible voltage modes on MS buses and within the whole distribution network. That diagram will help make the analysis of the voltage modes more clearly arranged than analytic calculations; moreover, it gives great opportunities for further study. Conclusions. Voltage deviation in the distribution networks has been performed and expediency of the voltage deviation control for electrically closest and farthest consumers have been analyzed in terms of Levanevska substation, town of Zaporizhzhia. Expediency of practical application of generalized diagrams for that purpose has been demonstrated. It has been defined that in the modes of maximum and minimum loads, voltage exceeds the admissible deviation norms of ± 5 %. Conclusion has been made on the expediency of more careful voltage control. Generalized diagram for 0-1 and 9-10 hours with the maximum voltage deviations has been constructed. Graph of dependences has been developed; formula of voltage deviations in the main substation, due to the voltage passing along that line, has been defined. According to the voltage data before and after the implementation of control, graphs of voltage deviations on the distribution transformer and in terms of the farthest consumer have been constructed.

CAD: Command-Level Anomaly Detection for Vehicle-Road Collaborative Charging Network

A large number of charging piles installed on roadside parking spaces and smart poles on the roadside of the Internet have become essential substation infrastructure (roadside) for building a vehicle-road coordinated charging network for electric vehicles. The management system of China National Grid’s network-load interaction includes the interaction between these main stations (traffic control stations) and substations (roadsides). The Internet-friendly interactive communication protocol for China’s vehicle-road coordination is IEC 60870-5-104 (104 protocol). The control network of the vehicle-road collaborative charging network has many characteristics, such as multiple levels, multiple types, and frequent information exchange for monitoring and control. Various types of operational information and control commands are subject to eavesdropping, tampering, and interruption during collection, transmission, and triggering. This paper proposes a command-level anomaly detection (CAD) method for a vehicle-road collaborative charging network. The CAD method analyzes the protocol for the specification format and business command characteristics of the 104 protocol. This paper uses the dynamic analysis protocol fuzzy test to realize the dynamic information in the program to guide the generation of test cases and pass the Markov state transition diagram. We describe the state transition and abnormality identification of protocol messages. We also design a long-term memory network to implement instruction-level anomaly feature mining. The experiment proved the validity of CAD. If we adopt other new protocols for the vehicle-road coordinated network in different countries or regions, the analysis of the new protocol can be completed in the same way, which has strong application value and prospect.

Designing of a distance protection stage based on data on branched line supply end currents

At present, in 110–220 kV transmission lines the problem of interphase short-circuits in the long-distance backup protection zone, in most cases, is solved by a backup level of current or distance protection. The existing protection solutions for lines with branching are based on the use of special high-voltage equipment, various current components and their ratios, a virtual resistance relay; on the control of emergency and orthogonal current components with adaptive braking and signal correction as well as with correction of the response characteristics according to the data on the voltage change and the state of the switching devices of the main substation. A number of developments are aimed at increasing the sensitivity of back-up protection of branch substations by changing the connection circuit, improving the response characteristics and refining the method for selecting the settings. However, these protection solutions in many cases do not provide the required sensitivity during short circuits on the low voltage side of a low-power branch transformer. All this means that an urgent problem to be solved is developing an algorithm for the operation of backup protection, providing the required sensitivity to short circuits on the low voltage side of the branch transformer. Analytical methods and simulation in the Simulink and SimPowerSystems packages of the Matlab modeling system were used to determine the impedance measurement of the distance protection measuring element. A mathematical model of the lumped-parameter line was used. When deriving analytical expressions, the impedances of the positive and negative sequences were assumed to be equal. Analytical expressions were obtained for determining the impedance measurement of the proposed and existing distance protection during phase-to-phase short-circuits appearing after a branch transformer and under load conditions. The studies have shown that the proposed distance protection has the required sensitivity to short circuits on the low voltage side of the branch transformer and the necessary detuning from load modes. The characteristics and methods for selecting response parameters of the additional stage of distance protection were determined using information on the currents of the line supply ends. The use of an additional distance protection stage developed by the authors based on the sum of currents of the line supply ends can ensure the required sensitivity to phase-to-phase short circuits on the low voltage side of the branch transformer with a star-delta connection circuit and solve the problem of distant backup protection of low power branch substations. The reliability of the data obtained is confirmed by the correspondence of the results of the analytical research and simulation modeling.

A simulation model of electric actuator unit of electric centrifugal pump with a submersible individual compensation installation

The substitution scheme and the system of differential equations for electrotechnical complex of producing well are given. The mathematical and simulation models of electric drive of electric centrifugal pump installation with submersible individual compensating installation are developed. The scheme of inclusion and practical realization of individual compensating installation consisting of the static capacitor battery with non-standard nominal voltage which is connected directly to the stator clips of submersible electric motor in a well is proposed. The simulation model of electric actuator of the electric centrifugal pump allows one to simulate the operation mode of electric actuator in steady-state and transient modes, as well as the group start of electric drives of electrical complex of the producing well. The optimal level of outgoing line voltage, energy parameters and the optimal parameters of individual, node and centralized compensating installations, as well as the rational voltage level of the main substation were determined from simulation.

Mechanical Properties and Numerical Analyses of Basalt Fiber Crumb Rubber Mortars in Soft Rock Roadways

The strength of crumb rubber mortars can be improved by the addition of basalt fibers. However, limited studies have been conducted on basalt fiber crumb rubber mortars (BF‐CRM), and the constitutive model is still very immature. In this paper, uniaxial compressive stress‐strain curves are obtained for several groups of BF‐CRM specimens with different contents. By comparison with the GZH model, modified GZH parameters that can be used in a BF‐CRM constitutive model are obtained. Then, taking the support scheme of the main substation of a mine as the background, FLAC3D is used to simulate the roadway support, BF‐CRM replaces the ordinary mortars in the original support, and triaxial compression tests are performed at different confining pressures. In this way, the application of BF‐CRM in roadway support is studied and analyzed.

Economic Scheduling of Microgrid Based on Energy Management and Demand Response

Abstract Currently, microgrids are regarded one of the main substations in distribution networks that generate electrical energy locally. The advantages of microgrids include easy management, optimization, and highly reliable supply. In this paper, the recommended model is based on economic and emission optimal scheduling in connection to the main grid mode; implementation model implies the short-term mode with optimal operation units and the use of real-time pricing (RTP) plan. In this study, a multi-objective function for operating costs and emission with the augmented ɛ-constraint method has been considered; fuzzy decision-making process has been employed to obtain the best solution. In addition, it has been considered that a microgrid has interruptible and shiftable loads that can participate in demand response programs. The presented results have been evaluated based on different demand response programs.

Unified traction power supply mode for trunk railway and urban rail transit

Based on the cophase power supply system in trunk railway and industrial frequency alternating current traction power supply system in urban rail transit, a novel unified traction power supply system of trunk railway and urban rail transit is proposed to realize the connection of trunk railway and urban rail transit with continuous power supply and no phase split. The novel traction power supply system is composed of the main substations and traction power supply networks which contain power supply networks, traction substations and traction networks. Stepped power is adopted in power supply network and traction network. Connection scheme of traction power supply networks between two adjacent main substations and its effect on suppressing equalizing current are studied. A novel contact power supply and power collection scheme is also proposed in this paper, in which contact power supply is realized by what is called “contact band”, power collection is realized by what is called “electric plough”. The advantages of contact band and electric plough are discussed. The main influencing factors of the voltage level of contact band are analyzed. The implementations of main substation traction scheme, separated power supply scheme and mixed power supply scheme are discussed. Segmented protection and state identification technology are elaborated in detail. Compared with current scheme, the novel traction power supply system proposed in this paper has many advantages and deserves further study.

Study of Transformer Lifetime Due to Loading Process on 20 KV Distribution Line

Power transformer is very important in electric power system due to its function to raise or lower the voltage according to its designation. On the power side, the power transformer serves to raise voltage to be transmitted to the transmission line. On the transmission side, the power transformer serves to distribute the voltage between the main substations or down to the distribution voltage. On the distribution side, the stresses are channeled to large customers or lowered to serve small and medium customers. As the power transformer is so importance, it is necessary to protect against disturbance, as well as routine and periodic maintenance, so that the power transformer can operate in accordance with the planned time. Some factors that affect the duration of the power transformer is the ambient temperature, transformer oil temperature, and the pattern of load. Load that exceeds the maximum efficiency of the transformer which is 80% of its capacity will cause an increase in transformer oil temperature. Transformer oil, other than as a cooling medium also serves as an insulator. Increasing the temperature of transformer oil will affect its ability as an isolator that is to isolate the parts that are held in the transformer, such as iron core and the coils. If this is prolonged and not handled properly, it will lead to failure / breakdown of insulation resulting in short circuit between parts so that the power transformer will be damaged. PLN data indicates that the power transformer is still burdened exceeding maximum efficiency especially operating in the work area of PLN South Bali Area. The results of this study, on distribution transformers with different loads, in DS 137, DS 263 and DS 363, show that DS 363 transformer with loading above 80% has the shortest residual life time compared to DS 263 and DS 137 which loading less than 80%.

Reconfiguration of Power Supply System Distribution 20 Kv: PT. PLN (Persero) Dumai Area Case

The electricity in Bagan Siapiapi is distributed 20 kV feeder distribution system. The main supply of Bagan Siapi-api from the Diesel Power Plant which is located ± 1.5 kms from the load center and the main substation of Duri is ± 102 kms from Bagan Siapi-api city through the Substation circuit Ujung Tanjung. The long distances between the Duri Mainstation and Bagan Siapi-api city resulted in a 14.85 kV end-voltage and a power loss of 988.7 kW. Voltage loss results in a lack of optimum service to the consumer and a large loss of network power become uneconomical for power supply operation. The result of end voltage calculation is 11,542 kV, and the power loss is 988.7 kW. After the main relay station in the village of Pedamaran operates, reconfiguration-1 produces the lowest end voltage calculation of 16.21 kV and a power loss of 136.59 kW, while reconfiguration-2 produces a low-end stress calculation of 17.37 kV and a power loss of 56.93 kW.