On the comprehensive measures of voltage quality r

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On the comprehensive measures of county-level power voltage quality regulation

voltage is one of the important indicators of power quality. Traditional power quality includes three aspects: frequency, voltage and reliability

1 determine the voltage central point and select the voltage monitoring point

for county-level power, the ultimate purpose of voltage quality regulation is to ensure that the voltage at the user's power receiving end is within the specified allowable deviation range. In practical work, it is impossible for us to monitor the voltage quality of each user, so it is necessary to select some representative power plants and substations as the central points of voltage monitoring. If the voltage quality of these points meets the requirements, the quality of other points in the power can basically meet the requirements

For example, relevant limit parameters such as current and voltage, working environment temperature and humidity, equipment load, etc.

the selection principle of county-level electric voltage central point is:

(1) high voltage bus of backbone hydropower plants and thermal power plants

(2) hub substation and main 110kV substation bus

(3) terminal step-down substation bus with important users

after the voltage central point is determined, the voltage adjustment of electricity is mainly the voltage adjustment of the central point

the allowable deviation range of central point voltage is usually based on the point with the largest voltage loss and the point with the smallest voltage loss. When the minimum voltage of the central point is equal to the maximum load at the county level, the lower limit of the user's voltage at the lowest point plus the voltage loss to the central point; The maximum voltage at the central point is equal to the minimum load at the county level. The upper limit of the user's voltage at the highest point plus the voltage between the central points. Users must pay attention to losses when selecting

the selection of voltage monitoring points should truly reflect the voltage quality offset level of most power receiving end users. The conditions for the safe and hazard free use of aluminum alloy cables in power system voltage and reactive power are: the aluminum alloy cables that meet the standard requirements and the supporting aluminum alloy connectors that are consistent with the cable performance, and the electric liquid crystal display fully meet the same kind of experimental force management regulations. It is stipulated that all substations and 10 (6) kV buses of power plants with county-level power supply loads are the voltage monitoring points of medium voltage distribution, A group of representative users shall be selected as the voltage quality assessment points, including 110kV and above power supply users and 35 (63) kV special line power supply users; For other 35 (63) kV users and 10 (6) kV users, at least one important user with high voltage requirements and the end user of representative lines on the 10 (6) kV bus of the substation shall be set for every 10000kw load; At least one voltage monitoring point shall be set for every 100 distribution transformers of low-voltage users. Instruments or meters with specific continuous monitoring and statistical functions shall be used for voltage monitoring. For unattended substation, the voltage of its bus shall be monitored and regulated by the dispatcher at the dispatching end

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