In the low-voltage reactive power automatic compensation, the reactive power consumption of the distribution transformer is not enough to compensate for the problem that the single power factor is affected. It is proposed that the automatic controller controls the switching of the phase control capacitor, which can compensate the reactive power consumption of the transformer and improve the primary power factor. What is the automatic compensation function of the distribution transformer? What is the point? (1) Reactive power consumption of distribution transformer The reactive power consumption of the transformer is the same as the active loss, which is also composed of iron loss and copper loss. The reactive power consumption of the transformer can be obtained by the following formula: Due to the reactive power consumption of the transformer, especially the no-load reactive power consumption, the power factor of the transformer itself is very low. (II) Influence of reactive power consumption of distribution transformer on power factor When assessing the user's power factor, it is usually to check the power factor value of the primary side of the transformer, that is, the active and reactive power consumed by the transformer also participate in the calculation of the power factor. If it is a user of high-voltage metering, the active and reactive power consumed by the transformer has already gone to the table. At this time, the power factor value calculated by the electric energy meter is the primary power factor; if it is the low-voltage metering user, the electric energy meter should be The power factor value calculated by copying the power plus the active and reactive power consumed by the transformer is the primary power factor. The metering method has no effect on the calculation of the power factor, but the load factor of the transformer and the power factor of the load are affected by the primary power factor. The lower the load rate, the greater the impact on the primary power factor, and vice versa. The load factor is determined by the production power usage, and the load power factor can be increased by capacitor compensation. What we want to discuss is that when the secondary power factor of the transformer is compensated, when the secondary power factor has reached 0.95 or higher, the reactive power consumption of the transformer has a influence on the primary power factor due to the low load factor of the transformer. The following is an example to illustrate. Here, the reactive power consumption of the transformer and its primary power factor are obtained by calculation. The calculated primary power factor value is equal to the power factor value measured at the same time. A user transformer is SJ type 10kV, 320kVA, short circuit voltage UK% is 4.5%, no-load current I0% is 7%, no-load loss P0- is 1.4kW, copper loss PK is 5.7kW, low-voltage electric energy meter monthly electricity The active power is 54720kW·h, the reactive power is 17920kvar·h, and the secondary side has capacitor compensation. 1. Calculate the resistance of the transformer's active loss transformer 2. Calculate the reactive power consumption of the transformer and so: It is not difficult to see from the above example that the secondary load is compensated by the input capacitor, and the power factor is increased to 0.95. However, due to the influence of the reactive power consumption of the transformer itself, the power factor drops to 0.85, which is 0.05 lower than the national standard. The above example is an SJ type transformer. Although the S7 type energy-saving transformer has less reactive power consumption than the SJ type, if the load rate is too low, the power factor is also greatly affected. (3) Automatic compensation for reactive power consumption of distribution transformers In the low-voltage power factor automatic compensation, the capacitor is placed on the secondary side of the transformer, and the automatic controller controls the switching of the capacitor according to the phase angle ø2 of the secondary load of the transformer, so the reactive power consumption of the transformer is not compensated; At no load, the automatic controller stops working because the transformer has no load current twice, and the no-load reactive loss of the transformer is not compensated. For the compensation of transformer reactive power consumption, some measures have been taken in the past, but the effect is not good. This paper proposes to change the original wiring mode of the controller in the automatic compensation of low-voltage power factor. The automatic controller controls the switching of the capacitor according to the magnitude of the phase angle ø1, which can compensate the variable reactive power consumption and the no-load reactive power consumption. , can achieve the effect of automatic compensation. 1. Connection method. The original voltage loop is unchanged, and the current is connected to the secondary circuit of the transformer primary side transformer. Since ø1>ø2, the purpose of compensating for the reactive power consumption of the transformer is achieved. 2, sensitivity. Control by one phase of the transformer. When the transformer is unloaded, the primary current of the transformer is only the no-load current of the transformer, then whether the no-load current of the transformer can meet the operating current of the controller, we take the S7 315kVA transformer as an example to illustrate. The sensitivity of the general controller is 50mA, the rated current of the primary side of the 315kVA transformer is 18.18A, the percentage of no-load current is 2.3%, and the actual ratio of the current transformer is 20/5, then: (4) Calculation of economic benefits 1 can save corporate electricity costs. High pressure metering of a weaving factory. After the wiring compensation, the power factor reached 0.98, and the annual electricity cost was 4,200 yuan. 2 Reduce the loss of distribution lines. Taking the textile line as an example, after 12 transformer compensation capacitors change the control mode, the annual loss of power is 10030kW·h, saving 300.09 yuan. 3 reduce system network loss. After changing the control mode, the system will lose 367.189kW·h of electricity per year and increase the electricity collection fee by 110.16 yuan. Universal Back Sticker, Back Film, TPU Back Sticker, Back Skin Sticker, PVC Back Sticker, Back Skin,Custom Phone Sticke,Custom Phone Skin,Phone Back Sticker Shenzhen Jianjiantong Technology Co., Ltd. , https://www.tpuprotector.com