Please adopt it.
Question 2: Solution to Three-phase Unbalance The three-phase voltage imbalance of power grid caused by unsymmetrical load can be solved: 1. Asymmetric loads are connected to different power supply points in a decentralized way, so as to reduce the problem of serious imbalance exceeding the standard caused by centralized connection. 2. The unsymmetrical load is reasonably distributed to each phase by cross-equivalent method and balanced as much as possible. 3. Increase the short-circuit capability of the load access point, such as changing the network or increasing the power supply voltage level, so as to improve the system's ability to withstand unbalanced loads. 4. Install the balancing device. Briefly describe the above technical measures to solve the harm of three-phase voltage or current imbalance to power grid and power quality. Which specific measures should be taken is more reasonable and effective, but also according to the actual situation, after technical and economic comparison to determine the implementation. In the low-voltage three-phase four-wire power supply system of urban residents and rural power grids, most users are single-phase loads or single-phase and three-phase mixed loads, and the load size and time are different. Therefore, the unbalanced current between the three phases in the power grid exists objectively, and this unbalanced power consumption situation is irregular and cannot be predicted in advance. Resulting in long-term imbalance of three-phase load in low-voltage power supply system. For the three-phase unbalanced current, the power department has almost no effective solution except distributing the load as reasonably as possible. The unbalanced current in the power grid will increase the copper loss of lines and transformers, increase the iron loss of transformers, reduce the output of transformers and even affect the safe operation of transformers, eventually leading to three-phase voltage imbalance. This problem is effectively solved by adjusting the reactive power compensation device of unbalanced current-automatic adjusting capacitor bank. The device has the function of adjusting unbalanced active current while compensating reactive power of the system. The theoretical results show that the three-phase power factor can be compensated to 1, and the three-phase current can be adjusted to balance. The practical application shows that the three-phase power factor can be compensated above 0.95, and the unbalanced current can be adjusted within 10% of the rated current of the transformer. According to Wang's Theorem, a capacitor connected across phases can transfer active current between phases. A reactive power compensation device for adjusting unbalanced current is designed by using Wang theorem. By properly connecting different numbers of capacitors between phases and between phases and neutral line, not only can each phase be well compensated, but also unbalanced active current can be adjusted. The reversing switch automatically selects the power supply phase through intelligent logic judgment and automatically adjusts the three-phase load imbalance. Reduce the loss of electric energy in the transmission process, maximize the utilization rate of electric energy, and enhance the reliability of power supply.
Question 3: How to deal with three-phase voltage imbalance? Voltage-current transformer can not be used to adjust three-phase voltage imbalance, because transformer is only a device to convert voltage or current in proportion. The function of transformer is to convert high voltage or large current into standard low voltage (100V) or standard small current (5A or 10A, both refer to rated value) in proportion, so as to realize the standardization and miniaturization of measuring instruments, protection equipment and automatic control equipment. Transformers can also be used to isolate high-voltage systems to ensure the safety of personnel and equipment. 1, the method to solve the current imbalance of three-phase load, carefully find the reason according to the actual situation, such as lighting system, check the number of lamps in each loop, according to the specification, the current of each single-phase loop should not exceed 15A, etc. After finding out the reason, the load capacity of distribution line is planned systematically as required, and the load of each single-phase loop is distributed reasonably to make the three phases tend to be balanced. At the same time, the three-phase load current of distribution line should be tested online, and the neutral current should be tested regularly. In the future construction, when selecting cables and press-fitting equipment, the cross-sectional area of neutral wire should be equal to that of phase wire, so as to fundamentally solve electrical accidents and electrical floods caused by dangerous temperature caused by serious imbalance of three-phase load. Connect single-phase users to phases A, B and C evenly to reduce neutral current and loss. At the same time, the total length of the single-phase load connection line should be reduced. 2. If the power factor of single-phase users is low, reactive power compensation should be carried out. Three-phase open-phase protector can also be installed. When any phase is broken, the power supply can be cut off immediately to eliminate the three-phase imbalance. Power-saving technology and products with three-phase balance system. Such as an economize of a three-phase balanced system. 3. The three-phase four-wire system should be adopted as far as possible for the low-voltage trunk and branch lines from the outlet of the public transformer to the power supply side of the household meter to reduce circuitous and avoid crossing. 4, regardless of overhead or cable lines, the phase line and the zero line should be a, b, c, o with different colors of wires or signs, and arranged in a certain order. Before the erection and assembly of low-voltage lines, the single-phase load users under the transformer should be uniformly planned and evenly distributed to the three phases of low-voltage lines, and records should be made. Check the off-line instrument structure correctly. The meter box number should indicate the phase, such as "* * line and one phase * *". After off-line meter reading is completed, it is necessary to check whether the three-phase load in the actual operation of low-voltage power grid is within the balance range and make some adjustments when necessary. (5) When developing users or changing users in the future, we should consider the problem of three-phase balance, form a normal mechanism in practical work, and constantly improve and perfect it. There is no absolute balance, but it should be relatively balanced. Based on the balance index, load investigation and analysis should be strengthened in practical work, and the maximum and average loads and development trends of various transformers should be recorded. The variable load current of Project 2 should be tested regularly, and the phenomenon of unbalance exceeding the standard should be found in time. At the same time, it is necessary to feed back the load analysis and organize targeted adjustments from time to time. Only in this way can we fundamentally control the occurrence of imbalance and avoid faults and accidents such as damage to electrical equipment.
Question 4: How to manage the three-phase imbalance? Characteristics of imbalanced governance module IGMGD;
1, low loss: fully passive product, low loss, about 50w/a.
2. Low temperature rise: H-class reactor is adopted, and the temperature rise is less than 25K.
3, high reliability: non-power electronic products, with perfect remote communication function, EMC design, strong anti-interference ability, anti-light load oscillation.
4. High cost performance: cheaper than SVG, equivalent to the price of ordinary compensation devices, and can correct active current. It can be used in combination with compensation to improve power factor.
5. High-end quality: unique theoretical calculation and control methods, products recognized by national patents, high-performance single-chip microcomputer STM32 series, unique control system and coding switch, integrated structure technology, and distributed network technology for control software.
6. Strong flexibility: modular design, small size, flexible combination, wall hanging, combination with compensation, outdoor and indoor installation, without changing the terminal phase sequence, and taking into account partial compensation. Automatic identification of phase sequence and flexible wiring between phases. Expandable and easy to install.
The three-phase load is unbalanced. Whether it is three-phase current or three-phase voltage, the three-phase imbalance management module IGMGD device can be used to solve the three-phase load imbalance problem.
Question 5: What should I do if the three-phase electricity is unbalanced after the transformation? 5 points to see if it is weak current, and strong current is not installed separately.
At present, home decoration lines are divided into strong current and weak current. Among them, strong electricity is generally divided into three roads and six paths. Three avenues refer to switches and lights, ordinary sockets, air-conditioning sockets and six paths, which are subdivided on the basis of three avenues.
1? lamp switch
2? Air conditioning special line
3? Kitchen special line
4? Bathroom special line
5? restaurant
6? bedroom
Generally speaking, a route passes through a pipe.
Strong current and weak current need to be separated. Failure to separate them will easily lead to tripping and short circuit, and whether the wire size is used correctly.
The wires used for strong current and weak current are different. Use the big line of 3-3.5 and the weak line of 2.5-3. .
Question 6: What should I do if the three-phase current is unbalanced? If the current is unbalanced at 40HZ, it may be a frequency conversion problem. If it's acceleration or deceleration, it may be time difference. If the vibration of 10HZ is serious, you can set a dangerous frequency band and skip this area with the most serious vibration.
Question 7: What should I do if the three-phase current is unbalanced? I can only adjust the three-phase load to balance as much as possible. There is no other way.
Question 8: How to solve the current three-phase imbalance? Just change the load configuration. If it is helpful, please adopt it. For your mobile phone, click Satisfied in the upper right corner. Thank you! ! .
Question 9: What should I do if the three-phase load is seriously unbalanced in the three-phase four-wire system? If you can't give two phases, you can only thicken the zero line, which will be safer!
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