RU2205490C2 - Single-wire distribution mains - Google Patents

Abstract

FIELD: power transmission to users. SUBSTANCE: distribution mains has power supply; three-wire line connected to the latter; isolating transformer whose primary windings are connected in star and secondary ones, in open delta, one of windings being differentially connected to two others; single-wire power transmission line connected to one of open-delta terminal leads; single- phase step-down transformer on user's end. EFFECT: facilitated organization of mains affording reliable power supply under normal and abnormal conditions. 1 cl, 2 dwg

Description

 The invention relates to electrical engineering and can be used to create reliable and cost-effective power supply systems for low power consumers, located at a considerable distance from the power supply nodes.

 Known distribution network, consisting of a two-wire line and ground, which is used as the third wire of the network [1].

 The disadvantage of such a network is the low reliability of power supply to consumers with out-of-phase modes and earth faults, as well as significant construction costs.

 Also known is a three-phase single-phase network [2], adopted as a prototype, containing an energy source, a three-wire network connected to it, to which two-wire branches are connected, at the end of which lowering single-phase transformers are included.

 The disadvantage of a three-phase-single-phase network is its inefficiency and low reliability of power supply in case of violations of normal operation.

 The objective of the present invention is to simplify the organization of the network while observing the requirements for the reliability of power supply to consumers in both normal and abnormal modes of network operation.

 This problem is solved by the fact that in a single-wire distribution network containing an energy source, a three-wire network connected to it, a step-down single-phase transformer, an intermediate transformer is additionally installed at the branch from the three-wire network main having a connection of the primary windings in the "star" circuit, and the secondary windings in an “open triangle” circuit in which one of the windings is turned on in opposition to the other two windings, while one of the terminals of the “open triangle” is connected ene to ground and via a second single-wire line is connected to one of the terminals of single-phase step-down transformer, a second terminal of which is connected to ground.

 The single-wire distribution network diagram is represented by Figure 1, and the vector diagrams of Figure 2 show the operation of the network in various operating modes.

 A single-wire distribution network contains a power source 1 (Fig. 1), a three-wire trunk of a network 2, an intermediate transformer 3, a single-wire line 4, a step-down transformer 5, and a power consumer 6.

 A single-wire distribution network provides electricity to consumers as follows.

In the normal mode of operation of the main three-wire network, a symmetrical system of phase voltages U _A , U _B and U _{C is} applied to the primary windings of the intermediate transformer (Fig. 2). At the terminals of the "open triangle", an output voltage U is formed, which at the end of the single-wire line is lowered by the transformer 5 to the consumer level. With common single-phase earth faults, such as phase A (FIG. 2), the phase voltages of the undamaged phases increase in the limit to the line voltages U ' _B and U' _C. The output of the intermediate transformer 3 and in this case there is an output voltage U '. Similarly, an output voltage will be present if an earth fault occurs in any other phase. In the event of a phase failure, for example A, the vector diagram of the primary phase voltages applied to the transformer 3 will occupy the positions U ' _B and U' _C. And in this case, the voltage U '' will be present at the output of the secondary windings. Similarly, the voltage is maintained if an out-of-phase mode of any other phase occurs.

 Thus, the use of a single-wire distribution network not only saves scarce bimetallic wire, but also increases the reliability of power supply during the most common operating conditions, and increasing the voltage on a single-wire line to a linear value allows to reduce power loss during transmission.

Sources of information
1. Kernoy V.V., Pospelov G.E., Fedin V.T. Local electrical networks. - Minsk: Higher School, 1972, p. 11 (Scheme 1).

 2. Kernoy V.V., Pospelov G.E., Fedin V.T. Local electrical networks. - Minsk: Higher School, 1972, p. 11 (Scheme 2 - prototype).

Claims (1)

 A single-wire distribution network containing an energy source, a three-wire network connected to it, lowering a single-phase transformer, characterized in that an intermediate transformer is additionally installed on the branch from the trunk of the three-wire network, having a connection of the primary windings according to the star circuit, and the secondary windings according to the open circuit triangle ", in which one of the windings is turned on in relation to the other two windings, while one of the conclusions of the" open triangle "is connected to the ground, and in Ora, through the single-wire line is connected to one of the terminals of single-phase step-down transformer, a second terminal of which is connected to ground.

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