SU1525808A1 - Method of shaping control setting of power overflow controller in inter-system connection - Google Patents

Abstract

The invention relates to electrical engineering and is intended for use in interconnection mode control systems. The purpose of the invention is to increase the efficiency of the use of weak communication of the energy combination under the conditions of the variable mode of communication operation. To achieve the goal, the power flow is measured by intersystem communication, the probability characteristics of the ordinates and the rate of change of the ordinates of the flow are calculated, by their values, the limit value of the flow and the specified number of time intersections of the limit per unit time, which corresponds to the required mode the reliability of the connection, compare it with the setpoint of flow and, based on the results of the comparison, form the setpoint. 1 hp f-ly, 3 ill.

Description

The invention relates to electrical engineering and can be used in intersystem communication control systems.

The aim of the invention is to increase the efficiency of the use of weak communication of the energy combination in the conditions of the variable mode of communication.

FIG. 1 shows a block diagram of the device that implements the proposed method; in fig. 2 and 3 - Comparison and Relay Unit, examples of execution.

The device contains a power flow sensor 1 over the power transmission line, a flow 2 summation unit, a random component allocation unit 3 in the power flow fluctuations, a probability flow characteristic calculation unit 4 of the flow flow fluctuations, a differentiating element 5, a unit 6 of the probability characteristics of the change of the ordinate power flow fluctuations , block 7 of forming the required value of the flow, body 8 setting the limit value of the flow, body 9 setting the average per unit time of the intersection of the limit value of current, unit 10 comparison and relay, organ

11Zadan flow setpoint and block

12 summing up the settings with a memory device.

The method is carried out as follows.

The measured value of the power flow through the power line from the output of the sensor 1 is fed to the input of the primary circuit.

 SP

CX)

about

00

2 summations of flows, where the summation of flows occurs if the interconnection is formed not by one, but by several power lines. The first output of unit 2 is connected with the input of unit 3 for the selection of a random component in the power flow fluctuations, and the second output is connected with the unit for comparison and generation of control action ARPM. In block 3, random flow oscillations are filtered, i.e. the low-frequency component of the overflow, which is transient in nature, as well as the rapid oscillations determined by the dynamics of the power system, are suppressed. Thus, fluctuations in the flows that have the greatest effect on the stability of electrical transmission, with a period from 0.5-1 to 10 minutes, are made. From the first output of block 3, the filtered signal of the power flow enters the input of block 4, where during the operation cycle of the device the calculation of such probabilistic characteristics of random oscillations of the flow, as the standard deviation of 6p asymmetry A and excess E,

Since the inlet of block 4 receives filtered random oscillations of the overflow, i.e. the regular component is suppressed, the oscillations can be considered centered. Then the indicated probabilistic characteristics will be determined by the following expressions:

E

BUT,

de Lp is the standard deviation (sko) of random oscillations by the exchange power; E - asymmetry and process excess

flow fluctuations; . 50 mathematical expectation of the desired value;

P - centered. E value of random fluctuations of the flow.

It follows that the practical definition of these quantities consists in erecting the filtered oscillations to the appropriate degree:

Q 5 0

Q,

0

for C.K.O. - in the second, for asymmetry - in the third, for the excess - in the fourth; connection during the cycle of operation of the device of the processes of change of the second, third and fourth degrees of flow fluctuation; dividing the corresponding averaged values by a cube C.K.O. for asymmetry and for the fourth degree of C.K.O. followed by subtracting the number 3 for kurtosis. Other options for calculating the likelihood characteristics are also possible.

From the output of the block 4, the values of C.K.O. asymmetry and kurtosis are fed to the first input of the block 7 to form the required value of the overflow. From the second output of the random component allocation unit 3, the filtered oscillations of the overflow arrive at the input of differentiating element 5, from which the signal of the rate of change of the ordinates of the flow fluctuations enters the input of the block 6 for calculating the probability characteristics of the rate of change of the ordinates of the fluctuations of the overflow. Block 6 calculates the CKO values. and the kurtosis of the rate of change of ordinates, which are fed to the second input of the block 7 forming the required value of the flow.

The averaging of the corresponding degrees of flow change processes filtered by band-pass filters, as well as the speed of change of the flow cross-section ordinates, is performed by a smoothing filter in the case of blocks 4 and 6 on an analog basis or by counting

one

mGh- - Y x - p.

  I -

five

0

five

in the case of executing these blocks on a digital basis (n is the number of signals, determined by both the duration of the device operation cycle and the quantization frequency of the signal over time).

The third and fourth inputs of block 7 from the outlets of the organ 8 setting the limit value of the overflow and the organ 9 setting the average per unit time of the number of intersections of the limit value of the overflow receive the corresponding specified values. In this case, both in the value of the specified limit value of the flow P, and in the value of the set average per unit time of the number of intersections of the limit value of the flow, additional corrections can be included.

The fifth input of block 7 from the first output of block 12, the summation of the setpoints to the sum storage device receives a signal of the current value of the setpoint, which in the first approximation can be considered equal to the mathematical expectation of the flow.

Block 7 generates, by incoming signals to its inputs, the value of the mathematical expectation of the power flow Fp, which is required to maintain the specified value

reliability of power transmission are used expressions:

-gu

For this7

R 21g

| ..-.

. (2 - BGW) | - |,

() +

24 (1)

Where

6v is the mean square deviation of the rate of change of the ordinates of the power flow; Z-- relative detuning. The calculation of the required value of the flow is best done using microprocessor technology. The solution of the transcendental equation (1) with respect to Z is the same and known methods (for example, the golden section method. When block 7 is performed on an analogue basis, determining the value of Z corresponding to a given mode reliability of the interconnection, possibly changing the value of Z, calculating Npn using the formula (1) and comparing it with the number of intersections of the limiting value of the overflow, given the average per unit time. When the discrepancy between them becomes zero, this will be the solution of equation (1) with respect to Z.

From the second output of block 7, the signal of the required value of the flow flows through the contacts 10.1 to the first input of the block 12, the summation of the settings with the sum memory device. From the first output of block 7, the same signal goes to the first input of the block, 10 compared to the first and relay, to the second input of which the flow setpoint signal is received from the first output of the organ 11, which sets the flow setpoint. The second outlet of the organ 11 through the contacts 10.2 is connected to the second input of the block 12, the summation of the settings with the memory device su

ten

15

20

. 25

thirty

we, where the given value of the overflow setpoint enters.

The design of unit 10 shown in FIG. 2, is required when the regulation of the flow continuously, except for the first cycle of operation, is carried out according to the required value of the flow generated by the unit 7. Such regulation is made according to the need for the maximum possible load of interconnection communication taking into account the requirements imposed on the operating mode reliability of communication. When a positive signal is detected from block 7, the relay 13 for monitoring the presence of a signal is triggered, closes its contacts 10.1 and opens the contacts 10.2. As a result, the unit receives a positive signal of the required value of the flow, which is memorized by block 12 and is controlled by the flow.

In the first cycle of the device operation, when the probabilistic characteristics are not yet calculated by blocks 4 and 6, and the block 7 does not generate a signal of the required flow value, the signal control relay 13 is inactive and the input of the block 12 receives a signal from the flow setting authority 11, which The first cycle is flow regulation. Thus, in this case, block 10 represents the actual signal monitoring relay.

The design of unit 10 shown in FIG. 3, is required when the regulation of the flow on the required value of the flow is conducted only at the indicators of the current mode reliability, the worst specified, i.e. when the required flow value is less than the specified setpoint value. If

45, the required flow value is greater than the specified setpoint value, i.e. the current mode reliability indicators are better than the specified ones; the regulation is carried out according to the specified setpoint value. This regulation is made when the free power of the transmitting power system is limited by some conditions (for example, in a dry year with water discharge at hydroelectric power plants) and the balance power flow implying interconnection should be constant or simply limited for a certain time interval. On this balance sheet overflow50

55

random exchange power fluctuations occur, therefore, continuous monitoring of the mode reliability should be carried out.

In this case, block 10 operates in a scant way.

In the first cycle of operation of the device, when there is no signal from block 7, relay 13 is open, therefore, there is no feed from reference 14 of relay 15, contacts 10.1 are open, contacts .10.2 are closed and input from block 12 is received from organ 1 1 set the flow settings. The adjustment in the first cycle of the device operation will be carried out according to the specified setpoint value. When a positive signal appears from the output of the block 7, the relay 13 monitoring the presence of the signal triggers, you close your contacts and the relay 15 characters can receive a boost from the reference organ 14. Relay 15 is activated only if the difference between the setpoint and the required value of the flow is positive, i.e. in the presence of a positive signal from the organ 14 of the comparison. In this case, the contacts 10.1 are closed, the contacts 10.2 are opened and the flow regulation is carried out according to the required value of the flow. When a negative signal appears at the output of the organ 14, i.e. for a given setpoint value greater than the required flow value, the relay 15 characters returns to its original position, closes the contacts 10.2 and opens the contacts 10.1.

When using the proposed method of automatic correction of the characteristics of the power flow regulator via intersystem communication, in comparison with the known methods for correcting the characteristics of the ARPM, the resulting operating mode increases.

 reliability of weak interconnection, i.e. the number of emergency disconnections of power transmission lines is reduced due to the excess of the exchange power of the power systems to the limit of the transmitted power of the transmission; the indicator of the possible number of power line outages for this reason is monitored during the process, which makes it possible to change the power flow in a timely manner to maintain a given mode reliability

five

Q 5 0 0 j

connection; and it also becomes possible to load the intersystem communication over the flow without reducing mode reliability as compared with the given one, which allows for 10–15% (and in some cases even more) with respect to the given detuning to increase the power flow and thus it is better to use the advantages of parallel operation of power systems.

Claims (1)

1. The method of forming the settings of the power flow regulator via inter-system communication, according to which its predetermined value is used as the initial flow setting, and then the changed settings are changed in order to increase the efficiency of using weak communication of the energy combination in the varieties of the variable mode of communication, measure the power flow over the interconnection link, extract the random component from the measured flow, calculate the root mean square 6p deviation, asymmetry A and kurtosis E fluctuations of the ordinate overflow, as well as the standard deviation 6h / and kurtosis E fluctuations in the rate of change of the overflow ordinates, according to their values, the limit value of the overflow P and the given average per unit time of the number of intersections by the exchange power power transmission N pr in terms of:   etc x (z -6Z +3) IT I; 1n-a P lr -m p where Z is the relative detuning of the power flow, calculate the required value of the flow rate Fp, which is used in the case of the difference of the obtained value from zero as a modified value of the setpoint flow. 2, the method according to claim 1, characterized in that in order to use it at power lines, the operating reliability of which, according to the operating conditions, must not be lower than the predetermined one, use the calculated value of the flow rate Pr in the case of a value less than the initial setpoint flow. The unit is aligned with J. and the generation ynpOD / tftch ig. 1 of the 6th decade ARTA  But 5k comparison equal to effect / fPHM // 10-2 12 one htL oFig .1 Fa.H.