SU691989A1

SU691989A1 - Method of limiting field and stator overcurrent of a synchronous machine

Info

Publication number: SU691989A1
Application number: SU772487348A
Authority: SU
Inventors: Виктор Семенович Костелянец; Максим Иосифович Покровский; Олег Иванович Яковлев; Олег Андреевич Леус; Татьяна Ивановна Дорина
Priority date: 1977-05-16
Filing date: 1977-05-16
Publication date: 1979-10-15

Description

1one

Изобретение относитс к электротехнике.The invention relates to electrical engineering.

Известны способы ограничени перегрузки синхронной машины по току статора и обмотки возбуждени путем измерени токов статора и обмотки возбуждени , сравнени их с заданной уставкой, фиксации наличи перегрузки в случае превышений заданной уставки и подачи сигнала на отключение выключател 1, 2 и 3.Methods are known for limiting the overload of a synchronous machine to the stator current and the excitation winding by measuring the stator currents and the excitation winding, comparing them with a given setpoint, fixing the presence of an overload in case of exceeding the setpoint, and giving a signal to turn off the switches 1, 2 and 3.

Недостатком известны) способов вл етс необходимость отключени синхронной маш.йны без предварительного воздействи на ее возбудитель в цел х ликвидации перегрузки ..A disadvantage of the known methods is the need to disconnect the synchronous machine without first acting on its causative agent in order to eliminate overload.

Указанный недостаток устранён в известном способе, вл ющемс прототипом изобретени 4, согласно которому при возникновении перегрузки синхронной машины по току статора или обмотки возбуждени эти токи измер куг, выбирают из них большую относительную величину, сравнивают ее с заданной зависимостью допустимой перегрузки обмоток статора и возбуждени по току от времени, формируют сигнал об истечении этой выдержки времени, срайнивают ток возбуждени с уставкой, задающейThis disadvantage is eliminated in the known method, which is the prototype of invention 4, according to which when a synchronous machine overload occurs in the stator current or excitation winding, these currents are measured, select a large relative value from them, compare it with the given dependence of the allowable overload of the stator windings and excitation to a current from time, they form a signal about the expiration of this time delay, they drive the excitation current with a setpoint

уровень ограничени тока возбуждени , фиксируют наличие превышени током вбзбуждени уставки ограничени и при по влении сигнала об истечении выдержки времени -допустимой перегрузки обмоток статора и возбуждени воздействуют через возбудитель на уменьшение тока возбуждени до уровн ограНичеНИ : the level of excitation current limiting, records the presence of an excitation current exceeding the limiting setpoint, and when a signal appears about the expiration of the time delay, a permissible overload of the stator windings and excitation affect through the exciter a decrease in the excitation current to the limiting level:

Недостатком прототипа вл етс то, что в р де режимов синхронной машины, в частности при пониженном напр жении на ееThe disadvantage of the prototype is that in a number of modes of a synchronous machine, in particular, under reduced voltage

зажимах, возникающа опасна дл обмотки статора перегрузка по току не приводит к .возрастаний тока возбуждени выше уставки уровн его ограничени , установленной, как правило, исход из номинального режима синхронной машины, и при этом синхронна машина может либо повредитьс , либо отключаетс защитами. .the terminals causing a stator overheating hazardous to the stator winding does not lead to an increase in the excitation current above the setpoint of its limitation level, which is usually based on the nominal mode of the synchronous machine, and the synchronous machine can either be damaged or turned off by the protections. .

Claims

The aim of the invention is to expand the functionality of the method. This is achieved by the method of limiting the overload of a synchronous machine to the stator current and the excitation winding by measuring the stator currents and the excitation winding, choosing from them a larger relative value, comparing it with a given dependence of the allowable overload of the stator windings and excitation over current from time, forming a signal about the expiration of this time delay, comparison of the excitation current with the setpoint of the excitation current limit, the detection of the presence of the excitation current exceeding the setpoint of the limitation and the occurrence of and from the expiration of Mi-, the time delay for the overload of the stator windings and the excitation through the exciter to decrease the excitation current to the limiting level, the voltage at the terminals of the synchronous machine is formed up to a voltage proportional to the disconnection of this voltage from the nominal and by this signal. stator overloads reduce the above set point setting the level of excitation current limit. The block diagram of the device implementing the described method is shown in FIG. one; in fig. Figure 2 shows the dependences of the stator current of the synchronous generator (/ s) on the excitation current (/ v) at nominal active POWER. ST. The device for limiting overload of the synchronous generator contains blocks 2 and 3 for measuring the currents of the stator and the excitation winding, respectively, block 4 for selecting the larger of NCK relative value, performing the function OR, and detecting the presence of overload in the stator current, block 5 comparing this value with the specified dependence of overload stator windings and current excitation from time and generating a signal about the expiration of this time delay, block 6 comparing the value of the excitation current with the statute that defines the level of current limitation ozbuzhdeni and fixations presence prevyschenn drive current setpoint slice level function block 7jvypoln yuschy And exciter 8 Measurement unit 9 the terminal voltage of the synchronous machine 10 and the signal generating unit. The proportional deviation of this voltage is bt the set value. The device operates as follows. The magnitudes proportional to the currents of the stator and the excitation of the generator 1, measured in blocks 2 and 3, are fed to the block 4 for selecting a larger relative value that performs the functions of OR and fixing the presence of a stator current overload. The selected large relative value is supplied to block 5, where it is compared with a predetermined dependence of the permissible overload of the stator stresses and excitation over time T and a signal is generated that this time delay has expired. In block 6, the magnitude of the excitation current is set by the setpoint, which sets the excitation limit level, and the presence of a revisit excitation current in the setpoint is set to the limitation level, which in block 6 is reduced by the signal generated in block 10 proportional to the voltage deviation at the terminals of the synchronous machine when it decreases from the set value. The voltage is measured in block 9. So, when a cTiaTopa overcurrent occurs and a lower voltage is applied at the terminals of the synchronous machine to a value of 0.9, the part of the excitation current limit level is shifted from the nominal value indicated by the dotted line a to the value marked by the dotted line li: nia b. Thus, the use of the described method will allow, under reduced voltage, to limit the overload of a synchronous machine - to the stator current and to increase the reliability of its operation in the power system. The invention method for limiting overload of a synchronous machine over the stator current and excitation winding by measuring the stator and excitation winding currents, choosing a larger relative value from them, comparing it with a given dependence of the permissible overload of the stator windings on the current versus time, generating a signal about the expiration of this time delay, comparing the excitation current with the setpoint of limiting current, detecting the presence of an excitation current by the setpoint of the limiting and when a signal appears The duration of the permissible overload of the stator windings and excitation, affecting the exciter through the exciter; reducing the excitation current to the limiting level, which differs by 7, with the aim of expanding the functionality of the method by limiting the overload of the synchronous machine when the voltage on its terminals is less nominal, additionally measure the voltage at the terminals of the synchronous machine, form a signal proportional to the deviation of this voltage from the nominal, and this signal in the presence of a current overload ora reduce the aforementioned setting specifying levels of drive current limitation. Sources of information taken into account in the examination