The line loss rate of a station area increases abnormally for several months, and the line loss rate of adjacent stations is obviously low or even negative. The line loss rate between stations is complementary.
The public transformer in the substation area does not correspond to the supplied users.
This phenomenon often occurs after the technical transformation construction in the substation area. The main reason is that the corresponding relationship between "transformation and household" in the substation area is not clear. Because most of the low-voltage lines in the urban area are buried cables, and the route of the lines is relatively concealed, but the original cables in the old area have not been labeled or updated for some reasons. Once the tables of the new public transformer need to be changed, it is easy to fail to correctly distinguish the subordination between the distribution transformer and the household table due to incomplete original data or unclear cable identification.
The marketing system did not update the corresponding information according to the actual "change and user" changes in time, so that the corresponding information of "change and user" saved by the marketing system did not conform to the actual situation, resulting in the deviation of line loss statistics.
Check and verify the corresponding relationship between "transformer and customer" in the station area with abnormal line loss rate. Call the marketing system to check the information of users in the platform area with the original data, check the actual sampling on site, and change the user information in the marketing system according to the sampling results on site. If the corresponding relationship between substation and household is not clear and the route of the line is not clear, it can be checked with the transformer by the substation area identifier, which can solve the historical problems simply and efficiently.
Abnormal phenomenon II
The original line loss rate in the station area is normal and stable for a long time, and it changes greatly in a short time, and then lingers near a certain value for a long time.
Wrong wiring or failure of the general table, sub table and TA of the common station.
Seasonal power consumption and temporary power consumption, power recovery, power stealing by users, master and sub meters of public station transformer, wrong wiring or fault of TA, power consumption after meter and Ta replacement does not enter the station area line loss report statistics, etc.
The following aspects shall be checked: whether there is temporary and emergency power consumption, whether there is power stealing in the area where the power is not included, whether the meter reading is in place, and whether the three-phase power supply line of the users in the area is balanced. If the line loss rate drops significantly, check whether there is temporary power recovery and storage.
Effective management of meters in the station area: establish complete user meter files, keep complete replacement records and failure table registration; regularly check the working status of the master meter and user meter to eliminate possible TA and meter wiring errors; promote the use of advanced energy meters to speed up the replacement of high energy consumption meters; install or remove energy metering devices in strict accordance with the system and process, and strictly prevent Collude with the inside and outside to steal electricity; adhere to the station area patrol, and find the hidden trouble of equipment as early as possible.
Abnormal phenomenon 3
The line loss rate in the station area is on the high side and the power factor is on the low side.
The line reactive compensation is not ideal.
Due to the understanding, management and system, the low-voltage reactive power management is extensive.
Low voltage reactive power local balance loss reduction. Install capacitors at the low-voltage side of the distribution transformer for compensation; install capacitors at the middle point of the low-voltage line or at the load concentration for compensation; and locally compensate the motor (random compensation).
Abnormal phenomenon IV
For a long time, the line loss rate in Taiwan area is high for unknown reasons.
It is usually caused by unbalanced three-phase load of transformer when common loss increasing factors are excluded.
In the three-phase four wire power supply mode, the neutral current is zero and the line loss is minimum under the ideal balance condition of the same load of each phase. In fact, due to the change of the power load of the power supply line in the substation area, the current of the neutral line cannot be zero, and the line loss of the neutral line cannot be ignored. Therefore, the technical specification for power supply stipulates that "in general, the current of the public neutral line shall not be greater than 25% of the rated current".
The power consumption of production is further increased, while the section of neutral conductor is generally 50% of the section of phase line, and the unbalanced loss increasing factors of three-phase load of transformer in substation area are increasingly prominent.
Therefore, it is necessary to reasonably adjust the load of each phase, improve the technical condition of the line, and realize the local balance and loss reduction of the three-phase load.
For the stations equipped with low voltage side network tables of distribution transformer, the operation records of distribution transformer can be transferred from load control management system to analyze data and check the real-time distribution of three-phase load distribution. In general, the unbalanced three-phase load of transformer can also be confirmed by load measurement in the distribution room, that is, the low-voltage three-phase four wire incoming current, the low-voltage three-phase four wire outgoing current and the neutral line to ground voltage can be measured in three different time periods, i.e. the low-voltage low-voltage low-voltage low-voltage three-phase four wire outgoing current and the power peak The three-phase load distribution of the time period is the benchmark.