SU855919A1 - Device for limiting synchronous generator excitation - Google Patents

Description

(54) DEVICE FOR RESTRICTING THE EXCITATION OF SYNCHRONOUS GG; GRDTOR

one

This invention relates to the automatic regulation of the excitation of synchronous generators.

Devices are known for limiting the upper and lower excitation limits of the synchronous generator 1 and 2.

The disadvantage of these devices is the separate execution of the upper and lower excitation limiters and the large losses in the measuring voltage and current circuits.

The closest in technical essence to the invention is a device for limiting the upper and lower limits of excitation of a synchronous generator, comprising generator voltage meters, a generator current meter connected to the input of the generator current to voltage converter, made on the active resistance. A resistor is used as a converter of the stator current into a voltage and to obtain a nonlinear characteristic of the reactive current as a function of the active current. The measuring body reacting to the voltage module is supplied with the geometric sum of the generator voltage and the aforementioned voltage from the active resistance. Typically, two limiters are used to control the generator mode: one for the upper limit limits and the second for the lower excitation limit 3.

The disadvantage of this device for limiting the excitation is that the resistance used to convert the generator current to voltage is significant and when using two limiters it is associated with the need to connect these resistances in series to the current circuit, which creates a significant load for current transformers. Considering that current transformers of generators are used both for measurement purposes and for accounting, their load is already significant, which in a number of cases makes it difficult to use excitation limiters. In addition, in active resistances occur

Claims (3)

20 significant voltage losses from the consumption of measuring organs of limiters, which in a number of cases leads to the output of the measured voltage beyond the limits of the apparatus settings, which can be used as limiters. The purpose of the invention is to simplify the circuit, reducing consumption and losses in the voltage and current measurement circuits. The goal is achieved by the fact that in a device for limiting the excitation of a synchronous generator, containing upper and lower limiters, generator voltage meters, a generator current meter connected to the input of the generator current converter to a voltage performed on the active resistance, different polarity meters of voltage meters generator terminals are connected to one resistance terminal of the generator current converter in a voltage, the second terminal of the converter resistance is connected to the same nnym input terminals limiter upper and lower limit excitation while other clamps gauges voltage generator connected to the second terminals of limiter upper and lower limit excitation .. In FIG. 1 shows the device; in fig. 2 a, b - vector voltage diagrams on the upper and lower limiters of the excitation in the modes of overexcitation and under excitation, respectively. The device contains I and 2 voltage meters of the upper and lower excitation limiters, active resistance 3 used as a functional converter of the generator to voltage, current meter 4 in the form of an intermediate current transformer, limiters 5 and 6 of the generator's upper and lower excitation limits. The device works as follows. The limiter responds to the voltage y (KiU + KJp) 2 + () and the generator voltage; lojlp- active and reactive components of the generator current; K | , K - constant coefficients, Under the conditions when the upper excitation limiter (overexcitation mode) is to be triggered, a voltage goes to its measuring body and 1- At the same time, the voltage of the lower excitation limit current goes to the measuring body of the lower limit, which is less than its setting (Fig. 2 a). Under the conditions when the exciter lower limit limiter should be triggered (under-excitation mode), the voltage U C is applied to its measuring unit, while the voltage supplied to the measuring body of the upper limit limiter and 4 is less than its setpoint (Fig. 26 ). Thus, the voltage generated on the active resistance is introduced into the measuring circuits of the upper and lower excitation limiters with opposite polarity. The excitation limiting device allows the use of a single functional generator current-voltage converter at the same time to limit both the upper and lower excitation limits, with half the consumption in current circuits. At the same time, the voltage drop across the resistance 3 from the current caused by the consumption of the measuring bodies of the limiters 5 and 6 is almost eliminated due to the fact that the currents simultaneously consumed by the measuring bodies of the stops 5 and 6 are opposite in phase. Apparatus of the invention for limiting the excitation of a synchronous generator, containing upper and lower excitation limiters, generator voltage meters, a generator current meter connected to the input of the generator current to voltage converter, made on active resistance, characterized in that, in order to simplify the circuit , reducing consumption and losses in the voltage and current measurement circuits, the opposite polarity of the generator voltage meters are connected to one resistance terminal generator current in the forming voltage, the second clamp resistance transducer coupled with similar input zazhi.mami limiter upper and lower limit excitation while other clamps gauges voltage generator connected to the terminals vtory.m limiter upper and lower limit excitation. Sources of information taken into account during the examination 1. USSR author's certificate No. 538468, cl. H 02 R 9/10, H 02 R 9/14, 01.24.73. 2. Labor VEI, vol. 81, 1970, p. 3. Author's certificate of the USSR L 613473, cl. H 02 R 9/10, 1975 (prototype). noo CHH J