The loss of power network is divided into management line loss and technical line loss. Manage line loss through management and organizational actions to reduce; The technical line loss is reduced by various technical measures. Technical measures to reduce network loss include measures that require increased investment in the technical transformation of the power network and measures that do not require increased investment only to improve the operation of the grid.

Due to various reasons, the power transmission and transformation capacity of the grid is insufficient, and the "jam neck" and the power supply radius are too long. These problems not only affect the safety and quality of power supply, but also affect the line loss. (1) Adjust the unreasonable network structure, set up new transmission and distribution lines, transform the original lines, increase the cross section of the wire, and use low-loss transformers. (2) Power grid boost, simplify voltage levels and transformer levels, reduce repeated transformer capacity.

Economic operation of power networks and equipment

Economic operation of power systems and networks The economic operation of power systems is mainly concerned with determining the combination of units and distributing loads economically. At this time, the economy of the whole system is considered, and the line loss is not a decisive factor. Therefore, under the premise of economic distribution of system active load, the economical operation of power network and its equipment is an effective measure to reduce line loss.

(1) Reasonable distribution of reactive power: When the active power is reasonably distributed, the reactive power should be reasonably distributed. In accordance with the principle of proximity arrangement to reduce reactive power long-distance transmission. Reasonable operation modes should be formulated for line loss calculation in various ways; Compensation equipment should be reasonably adjusted and used to improve the power factor.

(2) Determine the reasonable operation mode of the ring network: whether it is loop operation or open loop operation, and at which point open loop is related to the safety, reliability and economy of the power grid. In order to enhance the reliability of power supply and improve the economy of power supply, loop operation should be carried out, but loop operation will lead to the complexity of relay protection, thus affecting the reliability. In open-loop operation, the descaling point should be selected according to the calculation result of network loss.

(3) The reasonable operating voltage of the power network: the operating voltage of the power network has an impact on the no-load loss of the components in the power network. Generally, in the 35kV and above power supply network, increasing the operating voltage by 1% can reduce the loss by about 1.2%. To improve the voltage level of the power grid, it is mainly to improve the reactive power balance of the whole network, including increasing the voltage of the generator port, increasing the power factor of the user, using reactive power compensation device. Adjust transformer taps on the premise of reactive power balance. In the 10kV distribution network, because the no-load loss accounts for about 50% to 80% of the total loss, especially in the late night, because the load is low, the proportion of no-load loss is larger, so the voltage should be appropriately reduced according to the user's requirements for voltage offset. For low-voltage power grid, the no-load loss is very small, so it is advisable to increase the operating voltage. It can be seen that in the operation of the power grid, a large number of on-load voltage regulating equipment can reasonably adjust the operating voltage of the power grid under different load conditions.

(4) Adjust the load curve and balance the three-phase load: the load peak and valley difference is large, and the line loss is large in the case of the same power supply. When the three-phase load of the transformer is unbalanced, especially in the low-voltage network, the safe operation of the transformer is affected and the line loss is increased.

The loss of transformer accounts for 30% ~ 60% of the total line loss of the whole system, and reducing the loss of transformer is an important content of power grid loss reduction. Generally, in addition to the selection of energy-saving transformers, more than two transformers should be installed in parallel operation in the substation. This not only improves the possibility of power supply, but also can reasonably stop the number of parallel operation transformers according to the load, and reduce the transformer loss.

Reactive power compensation of power grid

Improving the power factor of the load Improving the power factor of the load can reduce the reactive power sent by the generator and the reactive power transmitted through the line and transformer, so that the line loss is greatly reduced, and it can also improve the voltage quality and improve the transmission capacity of the line and transformer.

The installation of reactive power compensation equipment should reasonably select the reactive power compensation capacity and determine the distribution of the compensation capacity according to the reactive power load and reactive power distribution in the power network to further reduce the loss of the power network.

The economic operation of smart grid is an effective way to reduce power supply cost. Reasonable selection of technical measures to reduce network loss is a very important work. In addition to understanding various technical measures, power grid management workers also need to choose more appropriate loss reduction measures according to the actual needs of the power grid, so as to get twice the result with half the effort.

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