SU915201A1 - Method of control of steam power plant power - Google Patents

Description

The invention relates to energy and can be used in thermal power plants (TPP) with power units, which are involved in power control in power systems.

The closest in technical essence and the achieved result is the method of controlling the power of a thermal power plant with at least two groups of power units, the first of which has lower maneuverability, by changing the load of power units in accordance with the distribution of the error signal between the groups and the total power and with taking into account the resolution formed on the basis of monitoring the exhaustion of the range of regulation of all energy blocks in the direction of increasing and decreasing the load [1].

The disadvantage of this method is reduced efficiency of the power plant, since, according to this method, power units are involved

2

in the regulation of system parameters, regardless of their maneuvering qualities and the magnitude of the total losses when the regime of a group of power units changes.

The purpose of this method is to increase the efficiency of the power plant.

To achieve the purpose of the distribution of the error signal, they are allowed to reduce the load of power units of the first group while exhausting the control range of power units of the second group in the direction of reducing or increasing the load, increasing the load of power units of the first group while exhausting the control range of power units of the second group to increase the load exhaustion of the regulation range of power units of the first group in the direction of reducing the load or when alichia range pe3 91

power units of the second group go up in the direction of increasing load.

Figure 1 is a diagram of the implementation of the proposed method ;, figure 2 diagram of the testing of the changing signal of the job.

In figure 1 it is designated: 1 - the block of a task of power of power plant,

2 - the regulating unit, 3 - the first integrator, 4 - blocks of the equity factors, 5 - blocks of limiting the task and 6 - the load adder.

All power units of the power plant are combined into two groups of the same type of power units: with smaller dynamic losses, more maneuverable, and with large losses.

8 in accordance with the division of power units into two groups, according to their type are also grouped the control circuits that form the N34.5 ^ signals of the assignment of power units - groups 7 and 8.

To implement the new operations, the second integrator 9, logic 10 and normally closed contacts of the control relay for the control range exhaustion upward (contacts 11) and decreasing (contacts 12) of the load of all power units of the first group and contacts 13 and 14 are introduced for the second groups of power units.

The integrator 9 is executed similarly to the integrator 3. Logic circuit 10 in general is a combination of AND, OR, etc. schemes that allow transmission of control actions along the influence circuit to integrators 3 and 9 if the load condition of the power units is acceptable and the specified sequence logical operations on the choice of chains of influence.

8 as a condition for the admissibility of a change in the load of a power unit, the presence of an adjustment range, not exceeding, can be considered. maximum permissible rate of change of the load of the power unit, etc. Circuit 10 can be implemented using both contactless elements and relay contacts.

The power control of power units of TPP proceeds as follows.

The task of the station is formed by block 1, which can be used as a communication device with

system regulator of frequency and power flows. The changed assignment to block 2 results in the appearance in the "add" direction (5) or subtract (m) of the control action at its output, which is transmitted via logic circuit 10 to the input of the integrator 3 of group 7 or to the input of the integrator 9 of group 8. After conversion in blocks 4 and 5, the control signal is fed as a task to the power units and as feedback through the adder 6 - to the input of the regulating unit 2.

For the case when all power units are divided into two groups: less maneuverable in the first (group 7) and more maneuverable in the second (group 8), and the desired loading sequence of groups provides; that power units of group 8 should be involved in the regulation first of all and only after their adjustment range has been exhausted - power units of group 7, the logic circuit 10 works as follows.

The circuit for reducing the load of the first group of power units is controlled by normally open contacts of the range exhaustion downwards and increasing the load of the second group, prohibiting the effect on the load reduction, this can be done by the power units of the second group provided that they are not at the maximum load limit. If Znar goblok of the second group are located on the border of maximum loads, then for power units of the first group it should be possible to reduce the load.

The circuit for increasing the load of the first group of power units is controlled by normally open contacts 13 of the range exhaustion relay towards increasing the load of the second group, prohibiting the effect of increasing the load, if power units of the second group can do this.

The circuit for reducing the load of the second group of power units is monitored by normally open contacts 12 of the range exhaustion relay towards decreasing the load of the first group and normally closed contacts 13 of the range exhaustion relay towards increasing the load of the second group, prohibiting this effect when supplied5

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The first group has the adjustment range provided that the adjustment range is exhausted in the direction of increasing the load in the second group.

The circuit for increasing the load of the second group is not controlled by the logic circuit 10.

In addition to the logic circuit 10, the influence circuit on the integrators of the groups is controlled according to the well-known 1 method with its range exhaustion relay: for the first group (integrator 3), the increase circuit is by contacts 11, and the reduction circuit is controlled by contacts 12; for the second group (integrator 9) "chain of increase by contacts 13, and chain of reduction - by contacts 14.

Figure 2 shows the timing diagram of the loading of groups of power units with a harmonic change of the reference signal, starting from the moment when both groups of power units have a margin of adjustment range in both directions.

From figure 2 it is seen that ^ as the time reference signal decreases,

nominal section 0-6, decreases the load of the second group of power units

^{and the} load of the first group (2 ^ e / 1. <&.) remains unchanged. The total load of the power plant (2 Ν ₃ λ5 _Λ ) varies in accordance with the change in load of the second group

At the moment of time b ^, the adjustment range of the power units of the second group in the direction of reducing the load is exhausted, and in the section ΐη –b ^ the load of the second group Σ ^ Ν _3α . _5λ . equal to its minimum and the continuing change of the reference signal Ν ^^ - reduces the load of the first group ^ _3Α5α αο of the moment b ^ when this load 2 Ν _3Α .5 _Λ becomes equal to its minimum

On the section b b ^ the load of the power station remains unchanged

^minimally

possible.

At time b _{3, the} change in the reference signal сигнала ₃ ^. _στ leads to the need to increase the load of the power plant, which is carried out by changing the load of the second group Nzd.5 _L with equal load of the first group and M ^^ to its minimum

5201 6

On the section b _p - 65 the load of the second group is equal to its maximum

and the change in the load of the power plant is made by changing the load 5 of the first group, until equality is established

^her ^ LzA5d ^maximum

In section b ₅ ~ b $, the adjustment range of both groups of power units in O, the direction of increasing load ^ is exhausted (Σ3 _{+ η}

At time 65, the load of the power units of the first group begins to decrease, and in b- | the second one. After '5 moment bd, the change in the load of the power station repeats its change at section b, χ - bd, becoming cyclic.

Thus, according to the proposed emitting method, a predetermined sequence of attracting different types of power units to power regulation in the power system is implemented. If this sequence changes, the logic must be changed.

The implementation of the proposed method allows to increase the efficiency of the power plant due to the involvement of more maneuverable power units in the regulation in the first place.

Claims (1)

Claim The method of controlling the power of a thermal power plant with at least two groups of power units, the first of which has a lower maneuverability, by changing the load of the power units in accordance with the distribution of mismatch signal between the task and total power, and taking into account the resolution, 45 formed on the basis of monitoring the exhaustion of the regulation range of all power units to increase and decrease the load, characterized in that, in order to improve the efficiency of the power plant, the distribution of the error signal is allowed to reduce the load of the power units of the first group while exhausting the power supply unit 55 groups in the direction of reducing or increasing the load, increase the load of the power units of the first group when the control range is exhausted 915201 θ power units of the second group in the direction of increasing the load and reduce the load of the power units of the second group while exhausting the control range of the power units of the first group in the direction of reducing the load or in the presence of the control range of the power units of the second group in the direction of increasing the load.