The compensator with series capaci tance of high series compensatnig degree
Technical field
The utility model relates to a kind of compensator with series capaci tance of high series compensatnig degree.
Background technology
Along with high pressure length apart from the applying of ac transmission network, the inductive reactance of power transmission line becomes the main factor of restriction circuit ability to transmit electricity.The method that solves this bottleneck at present has four kinds: one, increase erects power transmission lines, and improves the ability to transmit electricity from the sending end to the receiving end, and this kind method is costly, because the investment of one thousands of kilometers high voltage transmission line is tens billion of units.Two, on the way or be subjected to the in parallel or series connection fixed capacity compensation arrangement of electric terminals at power transmission line, this kind method can effectively reduce the influence of power transmission line inductive reactance, but will reduce the stability of whole network system greatly, as: may cause the subsynchronous resonance between cluster engine and the electrical network, cause unit to damage, even mains breakdown etc.Three, insert the thyristor controlled series capacitor device in the power transmission line loop, this kind method can effectively reduce the influence of power transmission line inductive reactance, and can change the equivalent impedance of power network line as required at any time, thereby guarantees the stability of network system.But this method price is comparatively expensive.Four, at power transmission line on the way or be subjected to electric terminals and connect static reacance generator or Static Var Compensator, according to the load needs, dynamic adjustments is idle.Thereby effectively reduce the influence of power transmission line inductive reactance, guarantee the stability of network system simultaneously.But this method same price costliness.
Summary of the invention
The purpose of this utility model is to provide a kind of compensator with series capaci tance of high series compensatnig degree.By resonance of serial connection in the power transmission line circuit the series circuit of work frequency increase network system in subsynchronous frequency range on the occasion of resistance, thereby improve the stability of network system and the compensativity of traditional series capacitor compensation.
The technical solution adopted in the utility model is as follows:
Scheme 1: in the middle of each the root power transmission line between first electrical network and second electrical network, insert resistance, transformer, the compensator with series capaci tance that inductance and another electric capacity are formed respectively by series compensation capacitance; One end of the former limit of transformer winding behind series compensation capacitance, is connect the power transmission line of first electrical network; The power transmission line of another termination second electrical network of the former limit of transformer winding; Resistance is attempted by the two ends of the former limit of transformer winding; Be attempted by the two ends of transformer secondary winding behind inductance coil and another capacitance series.
Scheme 2: in the middle of each the root power transmission line between first electrical network and second electrical network, insert resistance, transformer, the compensator with series capaci tance that inductance and another electric capacity are formed respectively by series compensation capacitance; One end of the former limit of transformer winding behind series compensation capacitance, is connect the power transmission line of first electrical network; The power transmission line of another termination second electrical network of the former limit of transformer winding; Resistance is attempted by the two ends of transformer secondary winding; Be attempted by the two ends of transformer secondary winding behind inductance coil and another capacitance series.
Said series compensation capacitance is fixed compensation capacitor or variable backoff electric capacity.
The utility model is compared with background technology, has the following advantages:
1) for traditional series compensation circuit, can improve the compensativity of series compensation greatly, the compensativity of series compensation is brought up to more than 90%, thereby improved the ability to transmit electricity of power transmission line greatly, save the electric power investment;
2) relatively controllable series compensation circuit, static reacance generator or Static Var Compensator can reduce the cost of device greatly;
3) can improve the stability of whole electrical network greatly, save the power grid operation cost.
The utility model can be widely used in the transmission line of ac high-voltage long distance electricity or need power consumer of series compensation etc.
Description of drawings
Fig. 1 is a structural principle schematic diagram of the present utility model;
Fig. 2 is an another kind of structural principle schematic diagram of the present utility model.
Embodiment
As shown in Figure 1, on the wall scroll power transmission line between first electrical network 1 and second electrical network 2 with an end of the former limit of transformer Tb winding behind series compensation capacitance C1, connect the power transmission line of first electrical network; The power transmission line of another termination second electrical network of the former limit of transformer Tb winding; Resistance R is attempted by the two ends of the former limit of transformer Tb winding; Be attempted by the two ends of transformer Tb secondary winding after inductance coil L1 and another capacitor C 2 serial connections.
As shown in Figure 2, on the wall scroll power transmission line between first electrical network 1 and second electrical network 2 with an end of the former limit of transformer Tb winding behind series compensation capacitance C1, connect the power transmission line of first electrical network; The power transmission line of another termination second electrical network of the former limit of transformer Tb winding; Resistance R is attempted by the two ends of transformer Tb secondary winding; Be attempted by the two ends of transformer Tb secondary winding after inductance coil L1 and another capacitor C 2 serial connections.
Its operation principle is: the operation principle of this circuit is: series compensation capacitance C1 is serially connected in the power transmission line between first electrical network 1 and second electrical network 2 and carries out reactive power compensation with the inductive reactance of offsetting transmission line; Inductance L 1 is formed the series resonant circuit of resonance on work frequency point with capacitor C 2, this resonant circuit provides the approximate zero impedance channel with transformer Tb and resistance R for the electrical network fundamental current, for other harmonic currents provide high impedance channel, make whole electrical network in subsynchronous frequency range, show positive resistance characteristic simultaneously, thereby can effectively suppress the subsynchronous resonance that electrical network may cause because of series compensation, increase the stabilization of power grids.The utility model can use single-phase, and in the electrical network of three-phase and heterogeneous transmission of electricity, wherein series compensation capacitance can be variable backoff electric capacity, perhaps is the fixed capacity compensation.