Key technologies for energy saving and consumption reduction of transformers
With the rapid development of urban social economy, the contradiction between energy supply and demand has become increasingly prominent. For the power supply and distribution system, it is particularly important to promote energy-saving and consumption-reducing technical measures and equipment. Transformers are the core power distribution and dispatching equipment in the power supply and distribution system. Their energy-saving and economical dispatching operation is the top priority of the energy-saving research of the power grid system. Reasonable measures to reduce transformer energy consumption are the key to the power supply and distribution system.
1. Key technologies for energy saving and consumption reduction of transformers
1.1 Use of new materials
In the manufacturing of transformers, the use of new materials instead of aluminum alloy or steel materials can enhance the corrosion resistance of transformers and reduce resistance, thereby achieving the purpose of energy saving and consumption reduction. At present, there are mainly two new materials that are more popular. The first is oxygen-free copper material, which can effectively reduce the internal resistance of the coil of the distribution transformer and achieve the purpose of energy saving and consumption reduction. Oxygen-free copper material has the characteristics of simple processing technology, convenient material acquisition and low cost, and it is also conducive to enhancing the ability of distribution transformers to resist short circuits. The second is to use amorphous alloy materials as the magnetic material of the distribution transformer. The iron core made of amorphous alloy materials can effectively reduce electromagnetic losses, thereby achieving the purpose of improving the economy of distribution transformers.
1.2 Installing an automatic voltage regulator
The loss of the transformer is closely related to the voltage of the distribution network. By installing the corresponding compensation capacitor on the load tap position of the transformer, the operating voltage of the distribution network can be appropriately optimized and adjusted. The automatic voltage regulator is a device that uses a three-phase coupling transformer to automatically adjust the ratio according to the actual input voltage value of the distribution transformer to ensure the stability of the output voltage, so that the input voltage value is automatically adjusted within 3% of the normal value, and the internal corresponding controller is used to control the voltage of the entire system in real time to achieve the maximum energy saving and consumption reduction.
1.3 Economic operation mode of distribution transformer
The energy consumption of the distribution transformer is not only related to the manufacturing materials and processing technology of the distribution transformer, but also has a great relationship with the operation mode of the distribution transformer. Therefore, optimizing the operation mode of the distribution transformer is the key to energy saving and consumption reduction of the distribution transformer. my country currently still adopts the traditional operation mode of the distribution transformer. This traditional transformer operation mode is not reasonable enough, resulting in high energy consumption of the transformer operation and failing to meet the requirements of economy. . In the actual distribution system, the non-power consumption compensation method can be adopted. The specific measures are to install parallel transformer reactive compensation components in the distribution system, so that the reactive power consumed by the inductive load can be provided. Commonly used methods also include: first, group compensation of distribution transformers, installing parallel non-power-consuming components at low voltage. Second, adopt advanced technical means to keep the three items of transformers in a balanced working state for a long time during operation. In addition, an important technical means to reduce the operating loss of distribution transformers is to make the distribution transformer basically balanced by adjusting the balance of three-phase loads. In actual distribution transformers, when the three-phase load is unbalanced, it will cause negative sequence voltage, causing the system voltage to fluctuate, thus affecting the energy consumption of the distribution system. When the three-phase distribution transformer is unbalanced, it will not only increase its own energy consumption, but also increase the loss of the line, so it is necessary to balance the three-phase electricity.
2. Analysis of measures for energy-saving operation of transformers
2.1 Optimize energy-saving and economical distribution transformers
In the process of selecting and designing the model and capacity of distribution transformers, energy-saving and economical products with low control loss rate should be selected on the basis of technical feasibility. For example, the S11 and S13 energy-saving and economical distribution transformers, which are currently used in engineering, have a control loss of about 30% lower than the S9 series transformers, and a control current of about 40%. At the same time, they have strong overload capacity and a more obvious comprehensive energy-saving effect. The S13 series distribution transformers have relatively small line losses and are more suitable for distribution systems with large load fluctuations, and can meet the engineering fields of modern distribution systems with large load fluctuations.
2.2 Energy-saving dispatching method using multiple distribution transformers for joint operation
With the continuous expansion of the scale and capacity of the distribution network system, the system load capacity changes frequently, and the losses under various operating modes are also very different. The optimal operating condition point and dispatching method should also change accordingly to achieve the purpose of energy saving and consumption reduction.
During the operation of the distribution transformer, the no-load loss and load loss generated by itself together form the active loss of the transformer operation, which will change nonlinearly with the load change. Among them, the no-load loss is a specific coefficient, which basically does not change with the change of the transformer load rate; while the load loss is a variable value that fluctuates with the load, and it is directly proportional to the square of the transformer load current. In the joint operation of multiple transformers, there is always a minimum point where the load factor is the lowest point, that is, the lowest point of the comprehensive power economic load factor of the joint operation of the distribution transformer. According to the actual situation of the distribution system, the optimal load operation point and economic load area of the transformer should be reasonably calculated, and multiple distribution transformers should be jointly economically dispatched and operated. According to the operating characteristics of the load from small to large, the optimal number of transformers and the control operation mode in different load areas should be calculated. The optimal economic operation area of the joint operation of multiple distribution transformers should be reasonably determined according to the comprehensive power load relationship to avoid the occurrence of non-economic operation conditions such as "big horse pulling a small cart", and effectively improve the power supply safety, reliability and energy saving economy of the distribution transformer.
2.3 Adjust the interphase unbalanced load rate of distribution transformers to achieve energy-saving and economical operation
Due to the large proportion of single-phase power load in distribution transformers and their power supply and distribution systems, and with the widespread promotion and use of various energy-saving electrical equipment, energy-saving lamps, etc., the three-phase load imbalance of distribution transformers, especially public distribution transformers, is large, and the corresponding loss is large. This shows that the load loss caused by three-phase imbalance is very large, which is a key point in the study of transformer energy-saving and economical operation. Through reasonable interphase load optimization adjustment, the three-phase load imbalance is reduced, and the three-phase load of the distribution transformer is almost close to the balanced relationship, so that a better interphase balance relationship can be obtained, the active loss and reactive consumption during the operation of the distribution transformer can be reduced, and the conversion efficiency of power distribution and scheduling can be improved.
2.4 Perform appropriate reactive compensation
From the operating conditions of the distribution transformer and its load curve with the load, it can be seen that the reactive load of the distribution transformer is mainly concentrated in the light load or no-load operating conditions, at which time excitation reactive power will be generated, and the reactive capacity consumed is about 10% to 15% of the rated capacity of the distribution transformer. Therefore, centralized reactive power compensation measures can be taken. By reasonably selecting reactive power compensation devices such as SVC, SVG, and TSC, the mortgaged reactive power compensation capacitors can be connected to the bus side of the distribution transformer through the load switch. When the system is operating under light load or no-load conditions, the capacitors can be reasonably switched to perform reactive power compensation in real time, improve the power factor of the 10kV distribution system, effectively reduce the operating loss of the distribution transformer, and achieve the energy-saving and economic effect of improving the end low voltage and improving the voltage quality.
III. Conclusion
In summary, in the distribution network, reasonable energy-saving measures such as selecting energy-saving distribution transformers, jointly economically dispatching multiple distribution transformers, optimizing and adjusting three-phase loads, and performing appropriate reactive power compensation can reduce the operating loss of distribution transformers and achieve the purpose of energy-saving and consumption-reducing economic regulation and operation.
