SU851628A1 - Device for measuring slipping of synchronous generator - Google Patents

Description

(54) DESIGN FOR MEASURING SLIDING SYNCHRONOUS GENERATOR

.one . The design of the system is electrical engineering and can be used as a fast-acting measuring element in the emergency control system of the power system. A device for measuring the slip of electric machines, consisting of a pulse speed sensor connected to the input of the first pulse length former, an AC voltage source connected to the input of the second duration driver, pulses, pulse generator connected to the second shaper inputs is known. the pulse duration, the output g of each of which is connected to the input of the key element connected to the input of the adder through a filter whose output is connected to the input of the amplifiers tel DC, an additional filter, the third key e "cient one input of which is connected to an amplifier DC, and the other input with the input of the first & th element of the key; the third input of the adder is connected to the output of the third key: the element is through an additional filter C × A disadvantage of the known device is the low immunity due to the use of analog signal for measuring the slip of the signal. In addition, the use of filters to convert a discrete signal to analog reduces the accuracy of the slip measurement. The closest to the proposed technical entity is a device for measuring the dynamic change of the angle of departure of the rotor of a synchronous generator and its derivatives, consisting of a sensor (speed of rotation of the generator connected to its output of the automatic control unit of the high-frequency pulse generator, measuring unit of the angle of departure, connected with an output of an automatic control unit and a high-frequency pulse generator, a storage unit containing exemplary and comparing pulse counters in, the counting inputs of which are connected to a high-frequency pulse generator, and the control is connected to the automatic control unit, and comparison elements, to the two inputs of which are connected the outputs of the reference and comparison pulse counters, and its output terminal is connected to the automatic control unit and to the control one by the entrance

a comparing counter, an arithmetic differentiation device connected to a departure angle measurement unit 21,

However, in the known device, the slip amount S is determined by differentiating the magnitude of the offset angle dP of the rotor of the synchronous generator using an arithmetic differentiation device. When ets, differentiation practically reduces to finding the spacing between the half period value corresponding to the model frequency fg of the tires of infinite power and the half period value corresponding to the current frequency f of the synchronous generator emf, i.e.

VQ-J)

where K is the proportionality coefficient.

The actual amount of slip is

. UU.T-TO To f t t

As can be seen from the above formulas, the amount of slip S obtained in the known device differs from the actual value of the slip by - f which causes the presence of error in the measurement of slip using the known device.

The purpose of the invention is to improve the accuracy of measuring the slip of a synchronous generator.

The goal is achieved by the fact that a device containing a generator rotation speed sensor, an automatic control unit, to the input of which a generator rotation speed sensor is connected, a high-frequency pulse generator, reference and comparing counters, the counting inputs of which are connected to the high-frequency pulse generator, and the control ones with a block automatic control, a dividing unit is entered, the first input of which is connected to the reference counter, the second input is connected to the comparison counter, and the third one is connected to the block automatic control and subtractor having a first input connected to the dividing unit, and the second - to the automatic control unit.

The drawing shows a block diagram of the proposed device.

The device contains a sensor 1 speed; rotational speed of the generator, an automatic control unit 2 connected to its output, a high-frequency generator of 3 pulses, a reference counter 4, used to measure the duration of the first integer following after the arrival of a signal from the half-time relay protection of the EMF of the generator taken as the reference, comparing counter 5, serving for measuring the duration of the current half-periods, starting with following the reference half-period. The counting inputs of both counters are connected to a high-frequency generator of 3 pulses, and the control ones - to an automatic control unit 2, the Device also contains a dividing unit 6, the first input of which is connected to a reference counter, the second input to a matching counter 5, and the third to automatic 2 control, IU and subtraction unit 7, connected to the division unit B, and automatic control unit 2.

The device works as follows.

Before the enable control signal from the automatic control unit 2 arrives from the relay protection, the blocks 4-7 emit zero signals.

In the event of an accident in the power system detected by the relay protection of the permits, the signal from the relay protection enters the automatic control unit 2. At the end of the half period, during which an accident occurred,

5, block 2 introduces an enable signal into a reference counter 4, which measures the duration of the first integer after a half-period failure by the number of NO pulses coming from high-frequency generator 3. The value is taken as the reference half-cycle corresponding to the frequency fo of the tires of infinite power. The NO number is stored in the reference counter 4 until the end of the transition mode. According to the signal of the automatic control unit 2 of the comparison, the counter 5 measures and records the duration of the half period -s-, following the reference, the number of pulses N of the high-frequency generator 3 pulses. Upon completion of the measurement of the half-period, the automatic control unit 2 outputs a signal to the operation of the dividing unit 6, in which the division of the number

NQ by N, which corresponds to the operation of dividing the value of the reference half-period by the value of the current half-period -3. With the start of operation of the division unit 6, the automatic control unit 2 resets the number N in the comparison counter 5 and gives a command to measure the next half period of the generator EMF. The signal from the output of the dividing unit b is fed to the input of the subtracting unit 7, where the signal from the automatic control unit 2 is subtracted from the unit. Thus, at the output of the subtraction unit 7, the slip value of the generator is output. After this, the automatic control unit 2 commands the following operation to be performed in the division unit 6 and in the subtraction unit 7,

After the end of the transition process and the arrival of the second signal from

Claims (1)

Claim A device for measuring the slip of a synchronous generator containing a generator rotation speed sensor connected to the input of the automatic control unit, the output of the high-frequency pulse generator is connected to the counting inputs of the reference and comparing counters, the control inputs of which are connected to the automatic control unit, characterized in that, for the purpose of increase the accuracy of measurement, division and subtraction blocks are introduced into it, with the first input of the division block connected to a reference counter, the second to a comparison counter, the third with an automatic control unit, the first input of the subtraction unit is connected to the division unit, and the second to the automatic control unit.