SU741370A1 - Device for emergency unloading of power system unit - Google Patents

Description

The device relates to power engineering and can be used in devices for additional unloading of power systems in the event of emergency situations with a large deficit of reactive capacity, resulting in the violation of the stability of the load nodes.

Unloading devices of the power supply unit 1 are known. A disadvantage of these devices is that they have a characteristic delay of 2-4 from the start of the implementation of emergency measures, which leads to a sharp increase in the volume of unloading, which is detrimental to the consumer.

Closest to the proposed invention is a device for emergency unloading of a power unit ECT eNttJ containing a current transducer associated with a relay element responsive to an increase in load current, a second relay element and a time relay, the output contacts of the relay elements connected in series with the winding of a time relay, and it is also equipped with an active power converter and a relay element responsive to

a decrease in active power whose input is associated with the output of an active ms converter of value 2.

5 A significant disadvantage of this device is that the device reveals only the fact of the violation of the load node stability in the zone of supercritical slip, not

10 determines the minimum amount of unloading required to ensure the stability of the load node.

The volume of unloading in the zone of supercritical slip significantly depends on the time of unloading and value

15 constant mechanical inertia of deigators. And only at the beginning of the transitional emergency T1rC) process, the magnitude of the load's disconnected power is minimal and does not depend on the value of the stationary mechanical energy of the engines.

The purpose of the device is to increase the reliability of the power supply of consumers by reducing the emergency power of the load.

This goal is achieved by the fact that a device for emergency unloading of a power system node containing an active power converter is equipped with a squared critical load voltage squaring unit, a squared equivalent EMF unit of the system, a voltage summation unit, a dividing unit, and an external resistance summation unit. network, the output unit of the summation, and the outputs of the squaring blocks of the critical load voltage and the construction in square-equivalent EMF of the power system are connected to the inputs of the voltage summation unit, the output of which is connected to the first input of the dividing unit, the second input of which is connected to the output of the summation unit, and the outputs of the dividing unit and the active power converter are connected to the inputs of the output summation unit. FIG. Figure 1 shows a graph of the dependence of the disconnected load (power) on the discharge time; in FIG. 2 is a block diagram of the proposed device. The output of the critical load voltage block 1 in quadratures and the output of the square block of the equivalent emf of the power system are connected to the inputs of the voltage summation unit 3, the output of which is connected to the first input of the division unit 4, the second input of which is connected to the resistance summation unit 5 the external network, the outputs of the dividing unit and the converter of the active power of the load are connected to the inputs of the output unit 7. The device works as follows. Under normal operating conditions, the power system's negative or zero output value of the output unit 7 of the summation blocks the output device acting on the load shedding. In an emergency situation, characterized, in particular, by an increase in the magnitude of the reactance of the external network Hsili by a decrease in the equivalent EMF of the power system E, at the output of dividing unit 4 there occurs a decrease in the value of the maximum permissible power consumption load1 (and Pfip and, if its value is less than the load power P, then a signal appears at the output of the summation output unit 7 that is proportional to the minimum required load power to ensure stability. The output device performs unloading put Simultaneous shutdown of consumers, the total power of which is equal to the difference between the limiting and current load power.Thus, the proposed device has the ability to shut off the minimum required load power, which significantly reduces the volume of emergency shutdown of consumers and increases the reliability of power supply to responsible consumers of electricity. achieve the specified goal. As is well known, an asynchronous load node with a homogeneous composition of consumers (for example, pumping stations of oil pipelines, gas pipelines, etc.) can be represented by an equivalent motor replacement circuit. Then the value of the maximum power RD of the equivalent engine is determined by the relation: 4 P.) where B, Xp are equivalent. Network parameters; reactive impedance scatter n engine. The magnitude of the resistance X is found from the expression of the CCR (2) 2P where P is the power consumed by the motor load; the value of the critical angle voltage without taking into account the external resistance of the network (X 0) Substituting (2) into (1) we obtain: m- The boundary condition for stable operation is equality consumed. And the maximum active power PP, from which taking into account (3) find the maximum allowable e my active load power sa. and Р „- -У Then.the value of the minimum required power to be switched off to ensure the stability of the remaining load is determined by the ratio POTK - P-VFormula of the invention The device for emergency unloading of the node power system containing an active power converter, in order to increase the reliability of power supply to consumers due to the reduction of emergency power, the unit for squaring the critical load voltage / unit for squaring the equivalent EMF of the power system is introduced into it, power accumulation unit, dividing unit, external power supply suppressor unit, output summation unit, with the outputs of the squaring blocks of the critical load voltage and squaring the equivalent EMF connected to the inputs of the summation unit of the voltages connected to the first input of the unit the second input is connected to the output of the cyt & mpomaHKa resistance unit, and the outputs of the division unit and the active power converter are connected to the input terminal of the scanned sum block.

Sources of information taken into account during the examination

I. Copyright Certificate of the USSR 489180 from 1973, kl.n 02 S 3/24.

2. USSR author's certificate 542292, cl. I am 02 J from 1974.

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Claims (1)

Claim A device for emergency unloading of a power system unit, comprising an active power converter, characterized in that, in order to increase the reliability of power supply to consumers by reducing the emergency shutdown power5, a block for squaring the critical voltage of the load, a block for squaring the equivalent EMF of the power system are introduced into it, a voltage summing unit, a division unit, an external network resistance summing unit, an output summing unit, and the outputs of the squaring blocks are critical the load voltage and squaring the equivalent EMF are connected to the inputs of the voltage summing unit, the output of which is connected to the first input of the division unit, the second input is connected to the output of the resisting unit, and the outputs of the division unit 5 and active power converter are connected to the input of the summing output unit