UA52793C2 - Set of facilities for merging two electrical power systems - Google Patents

Abstract

The proposed set of facilities for merging two electrical power systems contains two transformers which windings are connected according to the star-delta-11 and star-delta-1 circuits. The primary windings of the transformer are connected to the corresponding electrical power systems. To the secondary windings, two thyristor-reactor units are connected so that one unit is connected to the phases of the same name and the other unit is connected to the phases of different names. The load is also connected to the secondary windings. The proposed design provides for the possibility to isolate the electrical power systems at a short-circuit in one of the systems as well as to regulate exchange of active and reactive power between the systems.

Description

The invention relates to the field of electric power engineering and can be used in power distribution systems.

A known device for combining two power systems, which consists of three-phase transformers, the primary windings of which are connected to the power systems, and the thyristors, connected in a triangle and connected to the secondary windings of the transformers (A.S. Mo 936211 (USSR) Device for the unification of two energy systems / A.S.

Zekkel, L.A. Kotses, A.V. Posse and A.V. Cherkassky -- B.I. 1982, Mo 221.

Such a device reduces power flows and reduces the installed power of the equipment and does not allow to regulate the flows of active and reactive power, as well as the division of the combined two power systems in the event of short circuits and thereby reducing the levels of short circuit currents.

The closest in technical essence to the proposed device is a device for combining two energy systems, which has two transformers, the beginnings of the phases of the main secondary winding of the first transformer are connected in a star, and the ends of each phase of the main secondary winding of the first transformer are connected to the ends of the phases of the two additional secondary windings located on the adjacent magnetic cores of the first transformer, and the core of the second transformer is split into two half-cores, in addition, the primary windings are wound on both half-cores, on each half-core there are two secondary windings, connected in series, and each the phase of the additional secondary winding of the first transformer is connected phase-by-phase to the connection point of the secondary windings of the second transformer, and the free ends of the secondary windings of the second transformer are connected to the switching elements, (A.S. Me 1365239 (USSR) Device for combining two power systems / M.V.

Agunov, F.D. Goldenberg, D.A. Zaitsev and A.L. Kalinin -- B.I. 1988, May 11.

Such a device has low efficiency in regulating reactive power flows, does not regulate active power flows and power system division, and thereby does not ensure sufficient reliability of the power system as a whole.

The invention is based on the task of creating a device for combining two power systems, in which the limitation of short-circuit currents in power systems, as well as the regulation of active and reactive power flows between power systems, would increase the reliability of the power system as a whole and improve the quality of electricity.

The task is ensured by the fact that there are two transformers in the device for combining two power systems, the beginnings of the phases of the main secondary winding of the first transformer are connected in a star, and the ends of each phase of the main secondary winding of the first transformer are connected to the ends of the phases of two additional secondary windings , located on the adjacent rods of the magnetic circuit of the first transformer, and the rod of the second transformer is split into two half-rods, in addition, the primary windings are wound on both half-rods, on each half-rod there are two secondary windings, connected in series, and each phase of the additional secondary windings of the first transformer is phase-phase connected to the connection point of the secondary windings of the second transformer, and the free ends of the secondary windings of the second transformer are connected to the switching elements, according to the invention, two transformers, one with the connection group "star/delta - 11" , and the second - "star/triangle - 1", primary conditions wires are connected to the corresponding power system, and two thyristor-reactor groups are connected to the terminals of the secondary windings, one of which is connected to the phases of the same name, the other to different phases.

Such a scheme allows you to divide the power system into two in the event of short circuits, and thus to achieve a reduction in the levels of short circuit currents, as well as to regulate the flows of active and reactive power between power systems by means of an angular displacement between the secondary voltages of the transformers of both power systems by 60" and to regulate the amount of current through reactors with the help of thyristors, and thereby increase the reliability of the power system as a whole and improve the quality of electricity.

Fig. 1 shows the scheme of the device for combining two power systems, and Fig. 2 shows the vector diagram of voltages between the terminals of the secondary windings of transformers and currents, where 1 and 2 are three-phase thyristor-reactor groups TRH 1 and TRH 2, C is the first power system, 4 - the first transformer, 5 - the second power system, 6 - the second transformer, 7 and 8 - the load of the first and second transformers, respectively, A, B, C and A", B", C" - buses of the secondary voltage of the first and second transformers in accordance.

The device for combining two energy systems contains two transformers 4 and 6, one with the connection group "star/delta - 11" and the other - "star/delta - 1", which are connected by primary windings to two different power systems C and 5, the beginnings of the phases of the main secondary winding of the first transformer 4 are connected in a star, and the ends of each phase of the main secondary winding of the first transformer 4 are connected to the ends of the phases of two additional secondary windings located on the adjacent poles of the magnet wire of the first transformer 4, the pole of the second transformer 6 is made of two half-rods, in addition, the primary windings are wound on both half-rods, two secondary windings are located on each half-rod, connected in a coordinated series, and each phase of the additional secondary winding of the first transformer 4 is connected phase-by-phase at the beginning connection of the secondary windings of the second transformer 6, and the free ends of the secondary windings of the second transformer 6 are connected to the switching elements. Load 7 is connected to buses A, B, C of the secondary voltage of transformer 4, and load 8 is connected to buses A", B", C" of the secondary voltage of transformer 6. To the buses of the secondary voltage of transformers 4 and 6, two are connected thyristor-reactor groups TRG 1 and TRG2, where TRG 1 is connected to the same phases of transformers 4 tab, and TRG2 - to different phases of transformers 4 and 6.

In normal mode, the amount of current flowing through thyristor-reactor groups 1 and 2 is changed by a proportional regulator depending on the voltage in power systems Z and 5, as well as the shortage of active power in these power systems.

Power system separation is carried out by closing thyristors TRG 1 and TRG 2. In normal mode TRG1 It

TRH 2, which are connected to the secondary windings of transformers, allow changing the amount of active and reactive power flows between power systems Z and 5, thus regulating the voltage and frequency.

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Claims (1)

A device for combining two power systems, which has two transformers, one with the connection group "star/delta-11" and the other "star/delta-!I", the beginnings of the phases of the main secondary winding of the first transformer, connected in a star, and the ends of each phase of the main secondary winding of the first transformer are connected to the ends of the phases of two additional secondary windings located on the adjacent rods of the magnetic circuit of the first transformer, and the rod of the second transformer is made of two half-rods, in addition, the primary windings are wound on both half-rods , on each half-rod there are two secondary windings, connected in series, and each phase of the additional secondary winding of the first transformer is connected phase-by-phase with its beginning to the point of connection of the secondary windings of the second transformer, and the free ends of the secondary windings of the second transformer are connected to switching elements, which differs in that the transformers are connected to the corresponding power supply by means of primary windings topics, and two thyristor-reactor groups are connected to the terminals of the secondary windings, one of which is connected to the phases of the same name, the other to different phases.