Systematic solution for voltage quality evaluation and optimization of low-voltage transformer area distribution networks

Abstract

The invention discloses a systematic solution for voltage quality evaluation and optimization of low-voltage transformer area distribution networks. The systematic solution comprises the following steps: collecting topological structures, circuit parameters, phase sequence of tail end users, and load curve characters of the distribution networks in all low-voltage transformer areas to establish a low-voltage transformer area mathematical model; calculating average power or instantaneous power of users according to user consumption data in a marketing system of a power supply enterprise, and computing an active power, a line loss rate and each node voltage value of each section of a line through a forward-backward sweep distribution system power flow calculation method; performing optimal design and simulation analysis on the low-voltage transformer areas through modes of transferring load, newly increasing lines, changing lines and adjusting phase sequence to realize the optimal line loss rate and investment costs comprehensively. According to the solution, with a developed software platform, workload of line patrol and modeling in the low-voltage transformer areas can be greatly reduced, real-time data updating of the low-voltage transformer areas can be realized by basic-level power supply stations (offices) through combining with corresponding management measures, and the operation and maintenance level of the low voltage distribution networks can be improved.

Description

technical field [0001] The invention relates to a systematic solution method for voltage quality assessment and optimization, in particular to a systematic solution method for voltage quality assessment and optimization of a distribution network in a low-voltage station area, and belongs to the technical field of power systems. Background technique [0002] Voltage is one of the important indicators of power quality. Voltage quality is directly related to the safety and economic operation of the power system and the service life of electrical equipment. "Low voltage" and "stuck neck" have long been troubled by power supply problems in rural areas. How to Using low-cost methods to completely eradicate and cure this problem is the top priority of the new round of rural power grid upgrading and reconstruction projects. There are many reasons for the increase of rural low-voltage users, including irresistible factors, such as the rapid growth of rural electricity consumption cau...

AI Technical Summary

Problems solved by technology

[0004] With the continuous improvement of rural people's living standards, especially the policy of sending home appliances to the countryside stimulates the massive use of household appliances such as air conditioners, refrigerators, rice cookers, and induction cookers among rural residents, and even a large number of electrical appliances above the kilowatt level. The rapid development and the substantial increase in rural electricity consumption make it difficult for many distribution transformers to meet the requirements of normal and economical operation

[0005] (2) The line equipment is in poor condition

[0006] First of all, the construction time of the current operating lines is relatively early, and the technical requirements and construction standards at that time must not meet the current electricity demand in rural areas. Due to the phenomenon of insulation aging caused by long-term operation, the problem of low voltage becomes more and more serious

[0007] Secondly, the power supply radius of the distribution line is too large

Since the layout of substations in the rural power grid has not realized the power supply pattern of one township and one station, the geographical distribution of individual substations is unreasonable, resulting in the distribution of 10 kV lines with too long power supply radius, and the low-voltage line power supply radius seriously exceeds the standard requirements, resulting in large line losses, The phenomenon of low terminal voltage

Moreover, the layout of the transformer is unreasonable, so that it cannot go deep into the load center to achieve the most economical power supply radius, and the low-voltage power supply line is radial in one direction, resulting in low terminal voltage

[0008] Finally, the rural power grid is at the end of the power system, the reactive power supply is inherently insufficient, and the rural power load consumes a large amount of reactive power, resulting in a serious lack of reactive power in the rural power grid

However, due to the one-sidedness of understanding, it is quite common to pay attention to active power and ignore reactive power in rural power supply stations. The survey found that reactive power compensation is not in place in distribution stations with serious low-voltage problems in rural areas, and scattered in-situ There is basically no follower compensation. For example, some family factories have simple power distribution devices and do not configure reactive power compensation capacitors at all.

The centralized compensation device in the station area is useless, either the capacitor has been damaged, or it has not been put into operation

[0009] (3) Inadequate operation and management

[0010] First of all, part of the distribution network operation management is not in place, resulting in serious unbalanced three-phase load, excessive line loss, and equipment not in the optimal operating state, resulting in unstable voltage quality

[0011] Secondly, the low-voltage monitoring management system, organization, and responsibilities are not clear, and a complete low-voltage management system has not been established. Low-voltage data collection mainly relies on user complaints and voltage monitors, and the low-voltage normal analysis system has not been effectively carried out.

The monitoring, statistics, and analysis of the low-voltage power grid are not normalized, institutionalized, and the monitoring methods and methods are not systematic and complete, and the demand side management lacks effective means

In terms of operation management, the monitoring methods are relatively lagging behind, the layout of voltage monitoring points is not enough, and the monitoring is not comprehensive, so that the voltage analysis of the distribution transformer area is not in place, and effective measures cannot be taken in time

[0012] Thirdly, the management of user reporting, installation and connection is not detailed and standardized enough, and a large number of single-phase loads are used out of order, resulting in unbalanced three-phase loads in the station area, equipment not in optimal operating state, resulting in unstable voltage quality

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