•Dynamic thermal model of an indoor transformer station.•Buoyancy and air flow in kiosk transformer substation.•Influence of sun irradiation and wind to heating of an indoor transformer ...station.•Experimental verification of the thermal model.
This paper presents a dynamic thermal model of an indoor transformer station – transformer, high voltage and low voltage compartments are placed in a kiosk with inlet and outlet ventilation openings. The well-known dynamic thermal model of an oil immersed power transformer is extended with thermal models of walls and ceiling of the kiosk and natural air ventilation through the ventilation holes. The influence of wind velocity and the direction to convective heat transfer on each of the outer surfaces is taken into account. The solar calculator is developed and applied to determine the sun irradiation on each of the kiosk surfaces, taking into account shadows on some of the walls. The natural ventilation is modeled using equilibrium of pressure produced due to thermal buoyancy and pressure drop on the air path. The model is validated by comparing calculation results with the results of measurements on the transformer kiosk, with different surfaces of ventilation inlet and outlet openings. The model can be used in design phase to optimize ventilation openings (jalousies). Another application of the model is the estimation of the maximum possible load in forecasted ambient conditions, possible being applied in scope of smart grid concept.
The paper presents general aspects regarding the nature of loads that are generated and circulate in low voltage networks, the influence on the null conductor and the calculation of the actual value ...of the current on the null. The paper considers the measured values of null current in networks with deforming and unbalanced loads related to transformer stations. The calculation of power and energy losses in symmetrical and non-symmetrical balanced three-phase networks allows the determination of the CPT growth rate (own technological consumption) and its comparison with that determined from the graphs given by the standards. Balancing measures of phase loading and reduction of deforming regime are analyzed.
This paper describes a reliability study that has been performed at Hydro One to compare the reliability of two deterministic criteria used in the planning of high voltage auto-transformer stations. ...One criterion calls for designing the station to withstand the loss of one unit transformer (single contingency criterion) while the other calls for designing it to withstand the loss of two units (double contingency criterion). Two system reliability measures are used in the comparison namely the system availability index and the loss of energy index. The study proposed a number of Markov models to evaluate the probability of system failures under each criterion. Examples are provided to illustrate these models and see how the two deterministic planning criteria are compared from the reliability point of view.
The paper will present experiences in the reconstruction of the transformer station, which supplies the industrial factory. The previous version of the medium voltage (MV) substation with oil-filled ...transformers, and the new MV substation with dry and more energy efficient transformers, will be presented. An analysis of the operation and maintenance methods of oil transformers will be given. As oil transformers have many disadvantages, the reason, choice and cost-effectiveness of replacement with new dry transformers will be presented. Tests and measurements of insulation resistance of the winding and transformer protection during commissioning will also be presented. PT100 probes, which are connected to the thermostat, are installed in each low voltage winding of the dry transformer. Testing of this thermal protection of the transformer will be presented as well. Since transformers supply industrial consumers, mostly nonlinear ones, it is important to analyse the losses and life span of transformers. Nonlinear consumers lead to early aging of winding insulation, premature failures and reduction of transformer life. The newly designed and installed MV substation with Ring-main unit is ABB type SafePlus, and its installation and operating instructions will also be presented. The MV is equipped with a protection terminal, so settings and measurements of this terminal in transformer cells will be done. After the commissioning of the transformer station, the most important are diagnostics and periodic tests. Methods of periodic testing of MV substations will be presented in this paper.
Previous studies have shown that populations of multiapartment buildings with indoor transformer stations may serve as a basis for improved epidemiological studies on the relationship between ...childhood leukaemia and extremely-low-frequency (ELF) magnetic fields (MFs). This study investigated whether classification based on structural characteristics of the transformer stations would improve ELF MF exposure assessment. The data included MF measurements in apartments directly above transformer stations ("exposed" apartments) in 30 buildings in Finland, and reference apartments in the same buildings. Transformer structural characteristics (type and location of low-voltage conductors) were used to classify exposed apartments into high-exposure (HE) and intermediate-exposure (IE) categories. An exposure gradient was observed: both the time-average MF and time above a threshold (0.4 μT) were highest in the HE apartments and lowest in the reference apartments, showing a statistically significant trend. The differences between HE and IE apartments, however, were not statistically significant. A simulation exercise showed that the three-category classification did not perform better than a two-category classification (exposed and reference apartments) in detecting the existence of an increased risk. However, data on the structural characteristics of transformers is potentially useful for evaluating exposure-response relationship.
In the power distribution network , transformer station is the most common device, which is related with the power supply security , the landscaping , and has the most maintenance .It is also a large ...number device that realize standardized equipment very difficult . According to the original power distribution transformer station which has poor ability to withstand the natural disasters, unreliable operation, the low intelligent level, non-insulation, easy to rust, backward technology, environment is not harmonious and other problems, adopt the industrial design concept and method, developing standard modular all insulation transformer station. New type transformer station materials are advanced and reliable, complete all insulation,free-maintenance,have effect for security, anti-corrosion, environmental protection, beautiful, portable, simple.Further ensure personnel and equipment security, convenient operation and management.This article respectively introduces from the new type transformer station research contents, technical route, play the role, application effect and so on.
As an important responsible entity for promoting the energy revolution under the target of carbon emission peak and carbon neutrality, the power industry is exploring ways to save energy and reduce ...emissions in the five major links of the power system, namely generation, transmission, transformation, distribution, and end-use. As a key place to realize the voltage and current transformation in the power system, the transformer station also grows rapidly with the increase of the whole society's electricity consumption. This paper studies the carbon emission assessment and carbon reduction measures of a 35kV transformer station in Taixing, Jiangsu Province, China, namely "Guxi Station", which is to be decommissioned and upgraded in the second half of 2023. The life cycle analysis method and the emission factor method are adopted to trace and evaluate the whole life carbon emission after it is upgraded to 110kV level. The final calculation result is 68794.75 ton, of which carbon emissions in the construction stage account for 81.54%. From the perspectives of equipment carbon reduction, energy supply substitution, and building energy saving, several effective carbon reduction schemes have been proposed, which can reduce the whole life carbon emission by 61770.08 ton.
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