Abstract
- 1. The urgency of the problem of modernization of urban electrical networks
- 2. The use of deep input in urban electrical networks
- 3. Design of the "deep input" system
- 4. Distribution network with deep input system
- 5. Use of the circuit for household power supply systems
- 6. Advantages of the "deep input" system
- Conclusions
- References
The urgency of the problem of modernization of urban electrical networks
Over the past decades, the share of the urban population throughout the world is constantly and rapidly increasing. According to some forecasts, literally by 2050, urban residents will represent 70% of the world's population.
The growing pace of urbanization carries a huge burden for urban infrastructure and for the environment. An extremely important aspect of the development of the city’s infrastructure is an efficient and environmentally friendly electricity supply.
It is obvious that it is impossible to build power plants in the city, besides, the construction of high–voltage power lines of 10–20 kV from external power sources to consumers is unpromising. Therefore, the use of power input in power supply systems, as one of the ways to reduce losses in the transmission of electrical energy, is very important.
The use of deep input in urban electrical networks
Deep input is a power supply system in which the highest voltage is as close as possible to the electrical installations of the consumer. At the same time, the number of stages of intermediate transformation and apparatus is minimized.
The deep commissioning and crushing of substations at industrial enterprises has made the task of voltage regulation easier. Substations of deep inputs are located approximately in the center of the groups of localized power consumers. Voltages on the TSC tires do not differ significantly, which means that their regulation is much easier to implement. This means that a sufficient level and sufficient voltage quality can be ensured by using an auto–regulated transformer and automated capacitor batteries.
Design of the "deep input" system
With a system of deep bushings, step–down transformers 110/10, 35/6 or 35/0.4 kV can be installed at enterprises, and this significantly reduces the cost of installation and reduces power loss. Intermediate distribution points are not required, which are obligatory at GPP.
Distribution network with deep input system
Distribution network with the deep injection system can be in the form of radial or trunk lines. Radial diagrams of deep inputs 110–220 kV allow the use of the simplest primary switching circuits of deep input substations – the line–to–transformer circuit. When the main circuits are used schemes that allow you to disable the damaged transformer at the substation itself and re–enable the line with the automatic reclosing device.
Fig. 1 – Radial power supply with deep injection system
Fig. 2 – Trunk power supply system with deep injection system
Use of the circuit for household power supply systems
It should be said that the system of deep input has not yet achieved widespread use. It can be assumed that until recently, the reason for this was the lack of electrical equipment for the implementation of power supply systems using this system. Currently, this problem is almost solved.
In the electrical equipment market, high–voltage cables with XLPE insulation (XLPE insulation) with voltage up to 500 kV inclusive are offered. Started production of TMG–SESCH–35/0.4 transformers designed for operation in 35 kV electrical networks.
As the industry masters the production of current lines up to 330 kV with gas–insulated insulation, their use for deep–input circuits with a high density of the industrial site and the presence of an aggressive environment increases.
Advantages of the "deep input" system
From the foregoing, it follows that with a two–transformer PRT system, uninterrupted power supply to the responsible consumers is provided with the required power reserve of the selected transformers when using their permissible after–accident overload and the presence of ATS at the secondary voltage of the transformers.
It must be emphasized that without the use of simplified substation schemes for deep input and main switchgear, it would be practically impossible to introduce deep inputs and decentralize the system of receiving electricity (or the method of unbundling the main substation). This became possible without reducing the reliability of power supply through the use of automation.
Conclusions
The use of the system of deep inputs allowed: to increase the reliability of power supply, reduce capacitive currents and short–circuit currents, to abandon the construction of intermediate switchgears, reduce the length of the low–voltage network and thereby reduce power loss and voltage.
References
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- Тихомиров П. М. Расчёт трансформаторов. / П. М. Тихомиров. – М.: Альянс, 2016. – 528с.
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