DD293415A5 - METHOD FOR TASKS OF CONTROL IN MASTER HYDRAULIC PIPING NETWORKS - Google Patents

Abstract

The most important features of the method for tasks of control in intermeshed hydraulic or thermohydraulic piping networks: {state observation; modeling; Simulation; Control behavior; Error Behavior; Pipeline network; Fluessigkeitssystem; Control; Regulation; Print; Flow; Temperature; Meszstellenanordnung; Technical diagnosis}

Description

For this 1 page drawings

Field of application of the invention

The invention relates to the field of operation meshed hydraulic supply networks for the transport and distribution of liquids and is particularly applicable to the regime control of heat supply networks.

Characteristic of the known state of the art

The well-known principles for the technical design of the control of the regime, for the Meßstellenkonfigurierung and the diagnosis of the technichchen state of plants of meshed hydraulic and thermohydrauliscrien pipelines and supply networks can be characterized essentially by the fact that either from the knowledge de ^r object parameters (characteristics of pipelines and hydraulic organs) and predetermined values or measured values of regime parameters (generator and consumer volume flows, pressures in hydraulic fixed points) determine the control variables or the system condition assessment or with sufficient scope of measurement equipment (pressure and Volumenstrommeßstellen) the control variables or the system condition assessment directly or couple indirectly with measured variables. The first group is based on a theoretical analysis and, because of the inaccurate knowledge of plant and process characteristics, is heavily error-prone (the relative error expectation is 20% u.id above) and, due to the high computational time required, is of little use for the operative service.

The second-mentioned problem solution can be estimated as reliable, but requires a very expensive measuring point equipment and remote data transmission especially for large network expansions.

The patent search provided only a few references to solutions for the tasks of the control, the measuring point configuration or the technical state diagnosis in meshed hydraulic piping networks.

From the point of view similar solution requirements for the control can be found with restrictions on the patents for grid control in electric power systems, with a technical analogy is not directly possible. For the measuring point configuration 'mg in extensive networks, no provision is known, the searched patents represent technical functional solutions that are not relevant to the subject matter of the invention.

The current practice of controlling large mesh, intermeshed hydraulic piping networks with multiple pressure sources (feed-in points) and a greater number of pressure sinks (receivers) is characterized by a high degree of unreliability, which can lead to supply restrictions or over-provision of customers and which is not suitable. to solve the technological tasks in terms of cost and security.

Uncertainty is also present in the condition assessment of the plants of such hydraulic networks. Damage and breakdowns of systems and equipment can occur unexpectedly.

The aim of the invention is to ensure high supply and plant safety with cost-effective operation of hydraulic and thermo-hydraulic meshed pipe networks.

Explanation of the essence of the invention

The object of the invention is to establish a functional specification for the control of meshed liquid pipeline networks, to prescribe the distribution structure of sensors for pressures, flow rates and temperatures and to describe a diagnosis of the technical condition of the plant without necessarily knowing the object parameters of the installations and facilities and without the To assume knowledge of all regime parameters. According to the invention the problem is solved as follows:

Utilizing recognized relationships between pressures, volumetric flows and system pressure losses at various points in a closed pipeline network, the control signal parameters for the intended achievement of the values of hydraulic state variables or the most favorable measuring point distribution or the characteristic values for a state evaluation of the systems and facilities are determined. For the application of the invention, the relationships between the pressures and flow rates at different points of the pipeline network or pressure differences over flow sections or hydraulic organs are determined by statistical methods, with only a few of these variables at various system points as measured values or must be known. The number of required quantities depends on the structure and extent of a considered pipeline network and is related to the required accuracy in the solution of task relevant to the invention.

The determination of non-measurable hydraulic state variables is by extended use of the invention

meshed piping systems in a very short time possible, so that both the detection of disturbances (eg.

Load fluctuations in the heat consumers of a district heating network or plant defects) takes place very quickly and the Determining the correcting variables required for the disturbance compensation is possible quickly and safely. With the application

The costs of operating and maintaining hydraulic and thermo-hydraulic systems are negligible

Reduced supply networks, in the MSR equipment with pressure and Volumenstrommeßtechnik and the for the Signal transmission necessary technical means created by the possible savings in measuring points a significant Cost savings. With the implementation of plant diagnoses according to the invention or damage, after-appearance, Dirt and property deviations of technical equipment and system components of Piping networks safely and quickly recognizable and allow timely provision against unscheduled plant and Supply failures. exemplary Figure 1 shows a meshed hydraulic district heating network in terms of its structure. If, for example, a change in consumer heat flows is assumed to be a fault, then this both has an effect

the required total heat output of the generating plants as well as the distribution of the quantity of heating water to be circulated in the pipeline network.

Task of a control device, it is now, according to the procedure described with the following equation system

y = Fx + Gx, (1)

in which

y is the vector of the manipulated variables

x the vector of the measured variables (pressures Pmi to Ρμπ, volume flows V _M i to VMm, pressure differences p _M i to ρMq)

F the coupling matrix with statistically determined elements G is the matrix for the functional boundary conditions

are to determine the manipulated variables yi to y _P so that the measured variables reach their nominal values and at the same time the change of the generator output of the system optimally fulfills the requirements (eg minimum fuel heat costs or

Minimization of the total pump power). The classification of the control device with regard to signals to be recorded and output is shown in FIG. For the pipeline network described in Figure 1 pressure measuring points are locally determined so that with a minimum of Number of measuring points a complete observability for all network nodes is achieved. Starting from a reference model for the dependence of non-measurable nodal pressures p _N) on measurable knee pressures pm,

at fixed points of the network

Pn = M p _m (2) _t

in which M is the coupling matrix, the valid mounting locations are selected by several calculations for different mounting locations for the sensors for the size p _m) such that with the minimum number of sensors each variable p "i is at least one variable p _M jin a statistical dependence, whose correlation coefficient reaches a predetermined value, the z. B. 0.98

For the diagnosis of the technical condition of piping and hydraulic organs, the mass flow related Pressure loss or in the inverse of the relationship of the pressure difference dependent mass or volume flow in one

determined flow section as the basis for the determination of diagnostic characteristics by these variables are compared at different times with each other in order to derive therefrom the detection of fluid dynamic property changes.

If the state of the flow-through section i of a meshed pipe network according to FIG. 1 is to be evaluated, the pressure difference ρι, ι between the end points of the considered flow section can first be determined at time ti after prior determination of the volume flow V |, i. to determine:

(3, At time t ₂ , the characteristic W ^ is obtained analogously:

W ₁ , = 4 ^ (4)

2 | V

From the ratio D _vi = Wi, ₂ / W _u , the difference D ₀ I = Wi ₁₂ -Wi ₁₁ or any other suitable function with several recorded at different times or under different conditions characteristics of the imaginary or other kind may be based on the technical Be closed by making comparisons with known empirical values.

Claims (3)

1. Method for tasks of control in meshed hydraulic piping networks for the Transport and distribution of liquids, characterized in that the manipulated variables: - speed or performance of circulating pumps, - Injecting flows and pressures of pressure boosting systems and storage, - Positions of actuators and specifications for other pressure or volume flow influencing devices be determined depending on statistically determined relationships between pressures and flow rates of different points or pressure losses in the pipeline network or in hydraulic organs, the object parameters are not and the operating parameters only z.T. must be known. 2. The method according to claim 1, characterized in that the arrangement of sensors for pressures, flow rates and temperatures determined on the basis of statistically determined correlation conditions between said state variables and the significance of the o.g. Measuring sensors issued for the state observation of a particular pipeline network area is shown, with the most expedient arrangement of sensors can be seen. 3. The method according to claim 1 and 2, characterized in that in time sequence complexes of measured data hydraulic state variables or operating regime parameters and object parameters are determined, which are used for the detection of changes in fluid dynamic properties and thus enable a diagnosis of the technical system state.