Sun Kai (Heilongjiang Province Mudanjiang Electric Power Bureau Cable Area, Heilongjiang Mudanjiang 157000) The key link. Reducing the line loss and distribution loss of the power supply and distribution system, minimizing the reactive power and increasing the utilization rate of electric energy is one of the important issues in current building electrical energy conservation. The use of energy-saving technologies in power transmission and distribution circuits is discussed.
The power system itself is a large energy consumer, and the urban distribution network is the main part of the energy loss of the power system. Realizing the energy saving and consumption reduction of the distribution network plays a decisive role for the power company to increase economic efficiency and achieve target profit. Due to the rapid growth of load and the lag in investment in distribution network construction, distribution networks have great potential for energy conservation and consumption reduction. The loss reduction and energy-saving work of the urban distribution network not only can reduce the user's electricity expenses, improve the economic benefits of the enterprise, but also tap the power supply capability of the distribution equipment, and is extremely beneficial to the national energy utilization, environmental protection, and resource optimization. The relevant departments should attach great importance to it.
Since there are certain resistances in the electrical components in the transmission process of the power system, there will be power loss when current flows. The loss of this electric power during transmission in the transmission network is called line loss. Line loss is the loss of power generated by various equipment components and lines during the transmission and distribution of electrical energy in the power grid, including fixed losses, variable losses and other losses. The fixed loss means that the power loss of equipment or lines in the power grid does not change with the change of load, and the variable loss related to the applied voltage, equipment capacity and product quality means that the power loss of equipment and lines in the power grid changes with the load current. Variety. For example, copper loss of transformers, copper losses of coils of other equipment, and variable losses of transmission and distribution lines and other losses refer to losses caused by poor management during the supply and use of electricity.
2 Technical measures for reducing energy consumption in power transmission and distribution systems Urban power grids can reduce line losses through reasonable grid planning. The power sector can make full use of dispatching automation systems, online loss detection systems, and load monitoring systems to improve line loss management. For example, computer software is used to perform forward flow calculation and power flow analysis. When the major changes are made, the load flow calculation shall be carried out in a timely manner, and the best operation mode shall be selected to minimize the loss; the dispatching automation system shall be used to formulate the economic operation curve of each substation main transformer, so that the main transformer substations will remain optimal or Close to the best operating condition to ensure the economic operation of the main transformer.
Use transformers properly. The loss of the distribution transformer is the main component of the loss of the distribution network. Therefore, reducing the loss of the distribution transformer is very effective in reducing the loss of the entire distribution network. The main methods are: use of low-loss new transformers, reasonable distribution transformers and your capacity.
2.2.1 The use of low-loss new transformers If the amorphous alloy core transformer is used, it features low noise and low loss. Its no-load loss is only one-fifth that of conventional products, and it is completely sealed and maintenance-free. low. The S11 system is currently a low-loss transformer that is popularized and applied. The no-load loss is about 75% lower than that of the S9 series, and its load loss is equal to that of the S9 series. Therefore, the use of low-loss transformers should be promoted in the construction of transmission and distribution projects.
Transformer economic operation refers to the lowest power loss of the transformer under the same conditions of transmission power, by selecting the best operation method and adjusting the load. The economic operation of transformers does not require investment. As long as the scientific management of electricity supply and electricity is strengthened, the purpose of saving electricity and improving power factor can be achieved.
The transformer's capacity, voltage rating, and core material are different, so the operating parameters are different. Therefore, the economic operation of the transformer is to select the transformer with the best parameters and the transformer operation with the best combination of parameters.
A large amount of reactive current in the power grid will lead to increased line losses, reduced transformer utilization, and user voltage drop. Reactive power compensation is one of the important measures to reduce the line loss by using technical measures. The rational distribution of reactive power is achieved while the active power is allocated rationally. Reactive power optimization is to reduce the active power loss of the network by adjusting the distribution of reactive power flow, and maintain the best voltage level, so as to achieve the purpose of reducing line losses. Reasonable choice of reactive power compensation methods, compensation points and compensation capacity can effectively stabilize the voltage level of the system and avoid a large amount of reactive power loss caused by long-distance transmission over the line. Reactive power compensation of the capacitor of the distribution network usually adopts a centralized, decentralized, and on-site combination; the automatic switching of the capacitor can be based on the level of the bus voltage, the direction of the reactive power, the size of the power factor, and the size of the load current. Divide the time of day and night, the specific choice should be determined according to the characteristics of the load power.
After the shunt capacitor is installed, the harmonic impedance of the system has changed, and it will amplify the harmonics of the specific frequency, which not only affects the life of the capacitor, but also makes the system harmonic interference more serious. Therefore, there should be additional filtering devices for locations with large harmonic disturbances and compensation for reactive power.
3.2 Series compensation refers to the installation of capacitors on long distance transmission lines to compensate for the line reactance, shorten the electrical distance and increase the stability of the system. By installing series compensation devices, it is possible to increase the power transmission capacity of long-distance large-capacity systems and achieve optimal allocation of resources in a wider range.
Multiple-circuit lines on the same tower means that two or more lines are set up on the same line tower to save transmission corridors and reduce construction costs. Under the increasingly tense situation of environmental resources, making full use of the space of the transmission line corridors and erecting multi-circuit lines on the same tower can achieve more transmission of electric energy while occupying the same environmental resources.
4 Selection of Distribution Lines 4.1 Expanding Current Carrying Level of Conductors According to the selection principle of conductor cross sections, the minimum cross-section conductors that meet the requirements can be determined. However, in the long run, it is not economical to use the smallest cross-section conductors. If the theoretical minimum cross-section conductor is increased by one or two levels, the cost savings from line loss reduction can be recovered in a relatively short period of time. After the cross section is increased, the reactive power loss of the line will also decrease. Since the service life of wires is generally more than 10 years, the economic benefits created by increasing energy consumption and reducing cross-sections are very significant.
4.2 Selection of Overhead Insulated Leads Overhead insulated conductors have great advantages. With the deepening of energy saving and consumption reduction of transmission and distribution lines, overhead insulated conductors will be further promoted and applied. The advantages of using insulated conductors are: a. Improve the reliability of line power supply. Lines with insulated conductors can prevent phase-to-phase short circuits caused by external forces and special conditions, reduce the number of power outages during the operation of the crowbar circuit, reduce the maintenance workload, and increase the utilization rate of the line. The structure of the tower can be simplified, and it can even be laid along the wall, which not only saves the material of the circuit, but also beautifies the environmental road. Reduce the power loss of the line and reduce the voltage loss, especially the overhead insulated wire, because the distance between the lines is very small, the line reactance is only 1/3 of the resistance of the ordinary bare wire line; d reduce the corrosion of the wire, extend the service life of the line .
Conclusion In summary, through the research on various energy-saving and energy-reduction technologies in transmission and distribution lines, the technical measures for reducing energy consumption in power transmission and distribution systems have been proposed. With the rapid development of our country’s economy and the continuous improvement of people’s living standards, electricity has become an indispensable part of the lives of people in both urban and rural areas.
In this situation, the power supply is very tight and energy saving has become an urgent task.
According to the actual situation of the company, the most appropriate energy-saving measures can be selected to achieve the purpose of saving energy and reducing consumption.
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