The Research On On-load Arcless Automatic Capacity Regulating Distribution Transformer Control System

The transformer is one of the main equipments in the electricity industry. It also consume energy during the transmission of electrical energy. The transformer loss is the largest in the entire power loss in our country, which accounts for more than60%of the total power loss. Lots of distribution transformers are used in the low-voltage distribution network, which make the power loss of distribution transformers occupy30%i n the total transformers power loss. Therefore, developing and spreading the efficient energy-saving transformer become the main work in the field of energy saving in electric power system.The rural loads in our country have such characteristics, for instance electric centralized, seasonal load changing greatly, obvious difference between peak and valley and the low annual average load rate. Therefore, it is difficult to choose the proper capacity of distribution transformers. If the capacity of distribution transformers is chosen according to the average load or minimum load, then, it will emerge serious overload phenomenon in the peak of power consuming; If the capacity of distribution transformers is chosen according to maximum load, then, the transformer can not be fully operational in long time,and caused a lot of waste of electric energy. Based on these, the regulating capacitive transformer will not only make it run with the economic state under low load, but also make sure the transformer can supply enough power energy during the peak of consuming. Finally, it can reduce the comprehensive energy consumption of transformer. Therefore, researching regulating capacity technology of distribution transformer is of great realistic significance.According to the characteristics of China’s rural distribution network, and aiming at the shortcomings of no-load regulating capacity distribution transformers and mechanical on-load regulating capacity distribution transformers, this paper studies distribution transformer on-load automatic regulating capacity technology without arc.Based on the regulating capacity principle and loss reduction and energy saving principle, it proposes a kind of selection strategy of critical economic capacity for distribution transformer on-load automatic regulating capacity technology without arc. The method is selected based on the economic operation and calculates the critical economic capacity.Based on this, it analyses the relationship between the active power loss rate and the load rate of the on-load regulating capacity distribution transformers. Meanwhile, this paper takes the example of SZ11-M-T315(100) and S11distribution transformers, and compares the efficiency characteristics. In this paper, Calculating and analysising the dynamic loss of the on-load regulating capacity distribution transformers and the single capacity distribution transformer based on the daliy and monthly load curve, the results show that the regulating transformer has an obvious power saving effect.Based on the defects and shortcomings of existing regulating capacity transformer, the paper proposes the overall arcless on-load automatic capacity regulation design and regulating capacity switch arrangement.By calculating the withstand voltage and conduction current, it proves the feasibility about the issue which was proposed above that the thyristor is used as the regulating capacitive switch. Based on the introduction of thyristor working principle, characteristics and related parameters, the paper calculates the numbers of the thyristors series in thyristor valve group,and circuit parameters of dynamic and static average voltage.This paper proposes a kind of arcless automatically regulating distribution capacity control strategy. This control strategy bases on online load and the load prediction from grey load forecasting model, takes the actual data from a single-shift system as real examples, then regulates the capacity using the control strategy, which avoid the malpractice that causes by the regulating capacitive switch changes frequently. Build a simulation model for arcless on-load automatic capacity regulation distribution transformer under the MATLAB/SIMULINK,and simulation analysis the arcless on-load automatic capacity regulation distribution transformer to some single-shift enterprise, test and verify the validity and practicability of this control strategy.This paper researchs and designs the control system of arcless on-load automatic capacity regulation distribution transformer. The system captures the voltage and current data from low-voltage side of the transformer through a three-phase power metering chip ATT7022B, which generates a online load. The master chip ATmegal28sends corresponding control command. MOC3061low voltage side thyristor trigger circuit triggers the regulating capacitive switch which is corresponding to the low voltage side of the arcless on-load automatic capacity regulation distribution transformer, meanwhile, thyristor valve photoelectric trigger and online monitoring together triggers and monitors corresponding thyristor valve group of the high-voltage side of the transformer.According to the different kinds of optimization methods of arcless on-load automatic capacity regulation distribution transformer, this paper analyzes the caculation and simulation.The results show the scheme that is introduced in the paper is correct and effective.