First, the overall table and not on the points table
1. The issue of performance
A dormitory area, found that the cumulative power of the total accumulated charge table brought a few points to their table and not on, and vary greatly.
2. Analysis and Processing
This table is three-phase four-wire meter, it is the cumulative power should be brought in a few points of its own table of accumulated power and, so it is the basis for charges.
But under normal load, suddenly found the cumulative power of this form declined, and the accumulated data is always a big difference. Judging from the appearance of the table is not unusual, the rotation of the dial and counters and work were normal. Then check the end of the table if there is virtual connection wiring phenomenon, also found no abnormalities, the wiring is correct. But in the active table when the end of one of the lines (B-phase voltage line) and found that this line has a very soft (the lines are used in single-strand plastic hard wire), suspected internal metal part has been disconnected. After careful examination has confirmed that this phase circuit breaker.
As a result, the cumulative power of this table will be lost for the normal cumulative power 1/3. When the B-phase voltage circuit breaker, the cumulative power of this table is only A-phase and B-phase power sum. Since the B phase disconnected is this table instead of the current loop voltage circuit, so do not affect the sub-tables as well as user load carried by normal use.
Based on the above analysis shows that this failure is not normal. Because the total exemplar tail lines are connected by a single strand of plastic hard-line, and the metal part of the thick, usually from the inside is not easy broken. Thus, the many investigations and understanding fully proved this failure is indeed caused by man. Since the end of the table covers are sealed with a clamp closure has been unable to open, had to use pliers to break inside the metal, but the insulating sheath intact, it is difficult to be found, so as to achieve the purpose of stealing. This problem has to pay the relevant departments for processing.
Second, the correct choice of site energy meter measurement data
In recent years, more and more people focus on high accuracy measurement site current, voltage, phase, power and energy meter. To achieve this purpose, often through repeated demolition, wiring the high accuracy measurement instrument current transformer string into the circuit, which is neither safe and time-consuming. Meanwhile, with the increasing number of tests will lead to the junction box terminal screw slider, resulting in poor contact and even the current open circuit, causing the accident. However, the existing split core current transformers due to the opening, this will make the permeability coefficient is greatly reduced, and it is also a great relevance and location, which greatly limits the improvement of measurement accuracy, making the measured data generated suspicious. To solve this problem and to make full use of existing measurement instruments, the method is to first understand the additional error before the measurement itself split core current transformers produced, then the scene of the measured data by subtracting its own additional error The actual result is measured.
General field calibrator when calibration cycle in two steps. First, the voltage and current output of the calibrator voltage and current input and check devices are connected through a wire, then measure out of a set of data. The second is then split core current transformers wiring under the same conditions of load points, a second set of measured data, and finally subtracting the first set of data is the current clamp additional error with a second set of data.
As a result, this issue basically resolved, while the field test efficiency is greatly improved. Before the test site timing table, appear even larger error tolerance, measurement testers blind to conclusions, that the failure or poor performance in this table, it is not true, these test data may be related to inappropriate test methods and processing methods have relationship, it was not to forget.
Third, the power meter speed instability
Usually meter speed instability are caused due to mechanical failure. Such as:
1. When the meter on, leaving the lower bearing friction torque increases due to lack of oil, sometimes accompanied by the creak of friction vibration noise, so slow speed meter.
Approach: The case is open, the upper and lower bearings plus a little table oil, the problem can be solved. If the upper and lower pivot bearing is damaged or badly worn, may get a new device.
2. Due to the long-term use or due Meter poor quality brake magnet, resulting in loss of magnetic phenomena, so that the brake torque reduction, faster speed dial. Treatment: The brake magnets magnetized or replace magnet.
3. When there is debris between the magnets or iron slag, will slow when the fast speed dial. Solution: clean up debris and uneven dial corrected.
These phenomena are caused by unstable rotation meter main reason, but it can not be generalized. Meter speed and the above reasons related not only, but also, and it brought about the nature of the load. Three-phase three-wire power meter, for example, when it is purely resistive load (ie, the power factor is 1.0, Φ angle is 0 °), its two elements will have a rotational torque on the turntable. Its power is calculated as: PZ = UABIAcos (Φ + 30 °) + UCBICcos (Φ-30 °) [wherein: PZ is a total power; Φ is the phase angle between the voltage and the phase current; (Φ + 30 Angle] °) and (Φ-30 °) are line voltage and phase current.
When the load is inductive or capacitive (power factor of 0.5, Φ angle of 60 °), the two elements in one set of power is zero, so that its total power is half the total power of the original, of course, speed than the load is purely resistive slow speed when. Sometimes due to line load is constantly changing, so the speed meter will also change, but this is normal.
Fourth, the two tables are used interchangeably, resulting in power loss
1. The issue of performance
According to a unit dormitory electrician reflect a user based on his actual load and the usual power consumption to determine that the household electricity meter sudden drop in accrued consumption, the examination also found no anomalies.
2. Analysis and Processing
Based on the above, the officer decided to go to the scene to observe and analyze. After some time, relating to the measurement personnel came to the scene to observe this table, the table is not locked box, observation suddenly found table base and the number of original records in this table and are not on the housing list, but although there are seals end of the table did not cover seals. According to this series of case judgment, the user has the table may be replaced. To prove this user has stealing behavior, we decided to come back trip meter reading. Sure enough, the meter reading table and for a new face, whether it is a table base or numbers are right on the original recording. This family is undoubtedly use alternate use of two tables were stealing activities. That is the first half with a new table, in the second half with the original table (at the end of the meter reading). As a result, the cumulative power of the original table is only 1/2 of the normal cumulative power.
This problem has been handed over to the relevant departments for processing measurement.
Through the above analysis, summed up the root of this problem occurs mainly due to mismanagement. Such as: no formal meter box, seals are not in place and the work is not serious and the like. Therefore, a certain measure of staff from the ideological attention. Only the management and measurement of working closely together, in order to effectively avoid such problems.