• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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  • 优先权
    • 专利摘要:
    SUMMARY The invention relates to a method for regulating both the voltage on the primary side and the voltage on the secondary side on transformers, which are parallel or in parallel lines in electrical power systems and are equipped with means for changing the operation of at least two of the parallel transformers during operation. A system according to the invention comprises means which are arranged to be able to use independent winding couplers on at least two transformers, so that the winding coupling layers are selected in such a way that both the secondary side and the primary side voltage can be influenced, within certain limits, in a predetermined direction, or towards a predetermined direction. level, or against a predetermined interval.
    公开号:SE537599C2
    申请号:SE1400136
    申请日:2014-03-12
    公开日:2015-07-14
    发明作者:Daniel Karlsson；Sture Lindahl；Martin Bojrup；Lars Messing；Fredrik Sjögren；Tomas Johannesson
    申请人:Gothia Power Ab；
    IPC主号:
    专利说明:

    Technical Field The present invention relates to a method, a device and a system for regulating voltage in electrical power systems. The invention relates in particular to a device which controls the winding coupler control, for two or more parallel transformers, where at least two of the transformers are equipped with winding couplers, so that both the primary side and the secondary side voltage on each transformer are regulated by certain given limits. The invention regulates the voltage on the secondary side of parallel transformers in the traditional way, at the same time as the reactive power consumption in the parallel transformers is regulated by the invention so that it contributes to the voltage regulation on the primary side of the transformers.
    In addition to the option of using the winding couplers to regulate the secondary side voltage on parallel transformers in power systems with certain given limits, under the additional condition of minimizing the circulating currents, the winding coupler control is also used by the invention to consume reactive power in the transformers. to the voltage regulation on the primary side of the transformers by helping to lower the voltage when it is advantageous. For two identical parallel power transformers with identical winding couplers, the process meant that the secondary side voltage depends on the absolute law of the winding couplers (eg weighted sum or weighted average), while the circulating reactive current in the transformers and thus the reactive power consumption depends on the difference between the transformer layers. Since the voltage on the primary side of the transformers is affected by the reactive power consumption in the transformers, the voltage on the primary side can be affected by means of the winding switches, independently of the voltage regulation on the secondary side. Since the voltages depend on both the weighted turnover of the transformers and on the reactive consumption in the transformers, both the voltage on the primary side and the voltage on the secondary side can be regulated independently of each other. The phenomenon that with several independent control variables (in this case the law of the winding couplers), which affect the same process, regulate several quantities (in this case the primary side voltage and the secondary side voltage) separately and independently are called sarcoupling, in English decoupled control see for example [ Gilbert, E., G., "The Decoupling of Multivariable Systems by State Feedback", SIAM J. Control, Vol. 7, no. 1, February 1969].
    With transformers understood, all types of power transformers have the challenge that the turnover between the transformers' windings can be varied. With winding couplers, mechanical electrical couplers, semiconductor electrical couplers and other power equipment are capable of shaping the operation of a power transformer during operation. Background of the invention and state of the art Regulation of the voltage on one of the primary side and the secondary side, preferably the secondary side, on power transformers in electrical power systems by means of winding couplers, which with mechanical or power electronic switching changes the transformer turnover, is optional. There are also known methods for regulating the voltage of one side, in parallel operation of two or more transformers, with winding coupler control. The secondary condition for regulating parallel transformers with two or more winding couplers is often to minimize the circulating reactive current, in the parallel transformers [ABB Transformer protection RET670, Technical reference manual RET670 1.2].
    It is also the case that reactive power is generated in the distributed capacitances of overhead lines and cables and is consumed in the distributed inductances of overhead lines and cables as well as transformers in electrical power systems. The generation of reactive power in the power system is dependent on the voltage and is thus fairly constant (the voltage varies more than ± 5% around normal operating voltage), while the consumption of reactive power depends on the load (the load varies by about a factor of 4 on average, but locally significantly more). excess reactive power during low load time, especially in high voltage (typically Over 100 kV) overhead night and in cable night, and deficit of reactive power during high load time, especially in regional transmission night and in distribution night, with much overhead and relatively low voltage levels, then becomes a problem.
    Since the transfer of reactive power gives rise to active power losses, creates voltage drops in the systems and uses transmission capacity, it wants to compensate for reactive imbalances as close to the cold as is reasonably and economically possible. For a long time now, therefore, there have been shunt reactors on the main grid that are switched on under rated loads to lower the voltage and shunt capacitors on lower voltages 3 to keep the voltage up during high loads. The load on the power system as a whole has increased in recent years and shunt capacitors have also been installed at mains level. Furthermore, large parts of the medium voltage network in southern and central Sweden have been flooded through extensive cabling, which has led to large reactive power surpluses, which are currently transported up the systems during low load times, with increased voltages as a result. Therefore, shunt reactors have also been installed in regional transfer nights.
    Thus, there is a need to, preferably in lAglass situations, be able to consume reactive power in the power system. Achieving such consumption of reactive power and associated voltage reduction through other procedures and with the help of existing power transformers and existing high voltage equipment seems attractive. Objects and most important features of the invention An object of the invention is to provide a method, a method or a device for parallel power transformers, i.e. two or more transformers connected via one or more busbars and / or one or more wires on both the primary and secondary side, equipped with winding couplers (or equivalent power electronic equipment), where the winding couplers for the parallel transformers are regulated so that the secondary side voltage as the primary side voltage is regulated against predetermined independent voltage ranges, given by the desired mains voltage on the transformer side considered and the size of the winding switch stages.
    The need for the invention is mainly based on the following: 1) Reactive power surpluses give rise to active power losses and high voltages, especially in connection with widespread intermediate voltage cable and low load. 2) The current method of compensating for this reactive power surplus is to install shunt reactors, with or without winding couplers, whose only task is to switch on and consume reactive power for voltage regulating purposes. 3) With the help of the invention, the problem according to 1) above can be largely solved with the power transformers that other shells must have in the power system, a) whereby the need for investments in high voltage equipment, apparatus, control equipment, etc., is reduced in the power system; b) whereby the operational reliability of the power system increases as a result of fewer components; c) thereby reducing the environmental impact, as a result of reduced space requirements in plants and reduced need for shunt reactors, which often contain oil and are based on manufacturing processes with a negative environmental impact; and d) whereby the operability becomes better as a result of the fine regulation of the primary side voltage which can be achieved with the aid of the invention, compared with switch-coupled or winding-coupled regulated shunt reactors.
    These and further objects are achieved according to the invention by a method according to claim 1 or by a system or device according to claim 6 or by a computer program according to claims 11-13.
    According to a preferred embodiment of the invention, the method of regulating both the primary side voltage and the secondary side voltage is accomplished by suitably selecting winding coupler layers for each of two or more parallel transformers, so that the secondary side voltage is regulated to the lamp level by means of the winding couplers at the edge. such as minimum circulating current, Master-Slave, or the like, and that the primary side voltage thereafter, if required, can be collected by increasing the circulating reactive current through the parallel transformers, by increasing the distance between the winding coupler layers. Thus, the parallel transformers contribute with finely regulated reactive power consumption capacity, up to the transformers' capacity.
    In another embodiment of the invention, a computer program which controls a computer or a computer process comprises the control systems for winding couplers 30 of parallel transformers in accordance with the invention.
    In a further embodiment of the invention, inputs and outputs are adapted to be connected to simulation equipment, instead of to winding couplers of real transformers, such as various types of analog, digital or hybrid power system simulators [Edstrom, 6 A., Waive, K., "A Highly Interactive Fast Simulator Covering Transient Stability and Long Term Dynamics in Large Power Systems ", CIGRE Report 38-204, Paris, August 28 - September 3, 1994] Further developments of the invention fall within the scope of the following description, summary and patent claims.
    Brief description of the drawings The invention is described in more detail below with reference to the accompanying drawings, in which Figure 1 shows two parts of an electric power system, K1 and K2, respectively, with two parallel transformers, T1 and T2, between the power system parts, and the control equipment R, according to the invention. and control signals.
    Figure 2 shows an embodiment of the invention as a flow chart based on the components of Figure 1.
    In the control equipment it is examined whether the conditions 1Vp, ref-Vp1.
    The device according to the invention comprises a plurality of means / means, shown in the figures in river diagrams and block diagrams. These block diagrams can be interpreted as signal flow diagrams as block diagrams describing equipment for the device. A function challenged in a flow chart or of a block, shown in the block diagram, can in applicable parts be implemented by analog and / or digital technology, but is advantageously performed as a program in a microprocessor, in a computer program or as a computer program code element executed in a computer or in a computer process.
    It is to be understood that since the rivers and blocks shown in the figures are referred to as in a physical embodiment as devices, apparatus, etc., they are, in particular when the function of implemented as software in a microprocessor, to be perceived as a means of achieving a desired feature. Consequently, as it may be in this case, the term signal can also be interpreted as a value generated by a computer program and may also appear only in this form. The blocks below are only described as a function because they per se can be easily implemented by a person skilled in the art.
    In order not to burden the presentation with distinctions obvious to the person skilled in the art, the same terms are generally used below for the quantities appearing in lines, in automation devices and in calculation units, as for the food values corresponding to these quantities and signals / calculation values which are discussed below. described control equipment.
    Figure 1 shows two parts of an electric power system, K1 and K2, respectively, between which two parallel transformers, T1 and T2, 8 are connected, in such a way that the primary sides of the transformers are assumed to be electrically connected via busbars or sufficiently short wires in power system part K1 and secondary sides on the transformers are assumed to be electrically connected via busbars or sufficiently short wires in power system part K2. The pad transformers are equipped with winding couplers, LK1 and LK2, respectively, or similar devices, so that the conversion of the pad transformers can be done independently of each other. The control unit, R, is supplied with representative food values for voltage on the primary side, Vp, voltage on the secondary side, Vs, and at least one current on either the primary or secondary side, Ip or Is, for each transformer. With the control signals LKS1 and LKS2, respectively, from the control unit, R, the respective winding couplers are stepped to fulfill the control functions of the control algorithm, preferably 1) the secondary voltage as close to the setpoint as possible, a) within acceptable voltage range, set with i) as close to the drill bit as possible, given the voltage regulation on the secondary side without overloading any of the transformers with an acceptable voltage range, set with regard to i) the size of the winding switch stages.
    Figure 2 shows two similar embodiments of the invention as flow charts, based on the components of Figure 1. The process is started by reading relevant parameters. Then you enter a control loop which begins with regulation of the secondary side voltage and then of the primary side voltage. The control loop is then run through repeatedly for as long as the regulation is to continue. In the left flow chart, only one winding switch step is taken at a time to regulate the voltage on the secondary side before a corresponding winding switch step is taken to regulate the voltage on the primary side. In the right-hand flow chart, in the control loop, the required number of 9 winding coupler steps is first taken to achieve an accurate voltage on the secondary side. Only then is the voltage on the primary side regulated with the required number of winding switching steps to achieve an accurate voltage. Then the procedure is repeated so the Lange regulation pays off.
    The invention has been described above with reference to a number of different preferred embodiments. Of course, however, it is the case that the invention is not limited to these, but also a number of other embodiments are fully possible with regard to the scope of protection of the patent claims. 10
    权利要求:
    Claims (13)
    [1]
    A method for voltage regulation in electric power systems containing at least two voltage levels and at least two transformers, electrically connected and equipped to enable the operation of other respective power transformers, independently of each other, provided that the regulation of the conversion of two or more transformers used for regulating both the voltage on the primary side and the voltage on the secondary side, for two or more transformers not included in the transformation;
    [2]
    Method according to claim 1, characterized by co-coupled regulation of the voltage on the primary side and the secondary side, respectively;
    [3]
    Method according to claim 1 or 2, characterized in that the respective control layers of the turnover are used to regulate the voltage of the secondary side and that the difference between the respective control layers of the turnover is used to regulate the voltage of the primary side;
    [4]
    Method according to claim 1 or 2, characterized in that the voltage of the primary side is increased by stepping up the flap or winding coupler of some transformers and / or stepping down the winding coupler of some or other other transformers, in order to reduce some or some distance between the winding coupling layers and thereby reduce it. circulating reactive current; 11
    [5]
    Method according to claim 1 or 2, characterized in that the voltage of the primary side is reduced by stepping down the winding coupler of one or more transformers and / or stepping up the winding coupler of some or other transformers, in order to increase some or some distance between the winding coupler layers and thereby increase it circulating reactive current;
    [6]
    Voltage control system or device in electric power systems containing at least two voltage levels and at least two transformers, electrically connected and equipped to enable the operation of other respective power transformers, independently of each other, characterized in that the system is arranged to regulate the turnover of two one or more transformers input to the transformer to regulate both the voltage on the primary side and the voltage on the secondary side, for two or more transformers input to the transformer;
    [7]
    7. A system or device according to claim 6, characterized in that the system is arranged for sarcoupled regulation of the voltage on the primary side and the secondary side, respectively;
    [8]
    A system or device according to claim 6 or 7, characterized in that the system is arranged to regulate the voltage of the secondary side by regulating the respective control laws of the sales and that the system is arranged to regulate the voltage of the primary side by regulating the difference between the respective laws of sales;
    [9]
    A system or device according to claim 6 or 7, 12 characterized in that the system is arranged to increase the voltage of the primary side by stepping up some winding couplers of some transformers and / or stepping down the flag or some winding couplers of some other transformers, in order to reduce something or some distance between the winding coupler layers and thereby reduce the circulating reactive current;
    [10]
    A system or device according to claim 6 or 7, characterized in that the system is arranged to reduce the voltage of the primary side by stepping down a winding coupler of any or some transformers and / or stepping up a winding coupler of any other transformer, in order to increase some or some distance between the winding coupler layer and the clamed Increase the circulating reactive current;
    [11]
    Computer programs comprising program instructions for performing a method according to any one of claims 1-5.
    [12]
    A computer program according to claim 11 which, at least in part, is transmitted via a local or global network, such as an intranet or the Internet.
    [13]
    Computer readable medium comprising at least a part of the program instructions according to claim 11. 13 DRAWINGS K1, s - f • Vp, lp T2,1 — A, r-f LK2 LKS2 LK1 TtA • LKS1 ... ... Vs, ls
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    同族专利:
    公开号 | 公开日
    SE1400136A1|2015-07-14|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1400136A|SE1400136A1|2014-03-12|2014-03-12|Method and device for voltage control|SE1400136A| SE1400136A1|2014-03-12|2014-03-12|Method and device for voltage control|
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