ISSN 0040-6015, Thermal Engineering, 2006, Vol. 53, No. 5, pp. 395–398. © Pleiades Publishing, Inc., 2006. Original Russian Text © N.K. Chertkov, G.B. Barmenkov, B.B. Meshkov, 2006, published in Teploenergetika.

A Simulation System for Power Installations N. K. Chertkov, G. B. Barmenkov, and B. B. Meshkov OAO Chelyabenergo, ul. Rossiiskaya 23b, Chelyabinsk, 454002 Russia

Abstract—Problems of constructing dynamic computer models for training personnel are considered on the basis of developments by OAO Chelyabenergo. DOI: 10.1134/S0040601506050119

While training operational personnel of power stations, the main objective is relaying practical knowledge and developing experience in controlling the equipment. For this purpose, training simulators and computerized training systems (CTSs) are used as engineering teaching means. Creation of such means is connected, however, with high labor and financial expenses. For these reasons, introducing them meets with difficulties. When developing training simulators, the main intricacy is connected with the development of computer programs simulating dynamic systems. Recently, in different branches of science and industry, universal packages for visual simulation have become widely used in constructing models of objects. With the use of these packages, power-engineering equipment is successfully simulated. The MEUS system for simulating power installations was developed based on the American Vissim computer code, which is a dialogue visual envelope designated for constructing continuous, discrete, multifrequency, and hybrid models of dynamic systems. The Vissim standard menu contains a set of instructions for automation of solutions to many problems, along with a set of blocks, which must perform different linear and nonlinear functions. The MEUS system is a program for developing different teaching tools, as well as models for studying dynamic objects. In the course of developing the MEUS system, the possibilities of the Vissim code were extended by introducing new dynamic blocks, special modules, control and automation instruments, and a package of the means of graphic presentation of schemes, etc. The MEUS system is based on analog simulation of physical processes with the aid of digital computational technique. A model is constructed in the form of a structural scheme with the use of common means of simulation. The main elements of this scheme are blocks, modules, and connectors (commutation lines). Blocks and modules are incorporated into technological units. Each block performs a particular mathematical function. A module, including many blocks, executes a complex of 395

ps.s. BSV BCSV MSV BBSV ASV CV

Gs.s. ps.s. upstream of ASV SAS ps.s. downstream of CV ps.s. downstream of COV

ps. b1 SVB-1 SVB-2 SVB-3 SVIB SVP-WH

ps. b2 HPC

ps. IB GIB

ps. b4 CVIB SVB-4 SVB-5 SVB-6 SVHB CVHB

ps. b5 ps.HB LPC

ps.b.p. GHB Gc

Fig. 1. Structural scheme of PT-60-130 turbine model. SAS—steam-admission system; ps.s.—superheated-steam pressure; BSV, BCSV, MSV, and BBSV—bypass steam valve, bypass control steam valve, main steam valve, and blowdown bypass steam valve, respectively; ASV and CV—automated stop and control valves; SVB-1–SVB-6— steam valves of bleed-offs nos. 1–6; SVIB and SVHB— steam valves of the industrial and heating bleed-offs; SVPWH—steam valve of the peak network water heater; CVIB and CVHB—control valves of the industrial and heating bleed-offs; Gs.s.—superheated steam flowrate; ps.b1, ps.b2, ps.b4, and ps.b5—steam pressure in bleed-offs nos. 1, 2, 4, and 5; ps.IB and ps.HB—steam pressure in the industrial and heating bleed-offs; GIB—steam flowrate to industrial needs; ps.b.p.—steam pressure in the turbine back part; and GHB and Gc—steam flowrates to the heating bleed-off and the condenser.

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MMO 1

SVB-1

S1 UDTP

0.1

ps.b1 MDT

MMO

SVB-2 1

ps.b2

S2 UDTP

MDT

S3 UDTP

MDT

0.1

SVB-3

MMO 0.1 0.1 0.1

IB

pIB

1

Σ

IB

SVMWH

*

S4 UDTP

GIB MDT To RS

From LPC

Fig. 2. Structural scheme of the HPC technological unit. MMO—modulus of mathematical operations, MDT—modulus of dynamic transformations, and UDTP—unit for dynamic tuning of parameters.

1

* * Kob

+

1/S

Σ

+

–

Σ

1/S

– t

V>S 2 3 4 5

1/S

T1 T2

T3

x

e–sTd TLL

Fig. 3. Structural scheme of the modulus of dynamic transformations. TLL—transport-lag link.

mathematical operations. Commutation lines are the information carriers, which provide incorporation of blocks, modules, and units in the structural scheme of a model. At the OAO Chelyabenergo (regional power utility) teaching and training complex, CTSs of the PK-14 drum boiler and PT-60-130 cogeneration turbine are developed and used in the training process. These CTSs have the necessary functional capability of simulating equipment operation under different regimes envisaged by service instructions (preparation of the equipment, heating, start-up and shut-down, normal operation, operation under emergency conditions, etc.). The characteristics of the boiler and the turbine obtained experimentally during field thermal tests were taken as the main input data, along with the manufacturer’s diagram of the turbine regimes and the standard

characteristic of the turbine condenser. Mathematic models of the power installations were obtained by approximation of the experimental characteristics and other input data. Accuracy of simulation is determined by a comparison of the model characteristics obtained during its test with the corresponding parameters of the original. For CTSs under consideration, the simulation error is 5– 10%. In general, in the MEUS system, the accuracy of simulation is set while designing CTS, because we are able to correct it through information channels while tuning the model. The CTS models are fully transparent, obvious, convenient for tuning operations, and can be easily reconstructed; moreover, certain changes can be introduced into them, if necessary. This is important for adopting CTSs to the conditions of a concrete power station. THERMAL ENGINEERING

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A SIMULATION SYSTEM FOR POWER INSTALLATIONS

MEUS PT-60-130

ASV closed by protection

Inadmissible frequency of rotation

Live-steam temperature increase forbidden

Inadmissible axial shift

Live-steam temperature decrease forbidden 0

1

×100 t/h 2 3

Inadmissible rotor vibration

Inadmissible pressure of lubricating oil

Oil level in DT is inadmissibly low

TG switched-off by protection

Generator switched off

Oil-seal pumps stopped

Inadmissible pressure in condenser

TG switched off by remote action

Generator internal fault

×10 kPa 1 2 3

4

HP CTS are closed

PNO pumps switched off

Pressure in condenser

LP CTS are closed

×10 MW 4 0 1 2 3 4 5 6 7 8 0

Live steam flowrate

MPa 8 12

4

16 0

ps.s. upstream of ASV

Power

397

Stop

IS, %

100

93

MSV IS, %

0

3000 BSV

BCSV BBSV

COV

100

IS, %

Setting

100

IS, % CV-T

Setting

R

50 54.12

Hz MW Gen

TGD

rpm

FS

WS-5

SCS-1

% R 88.1 IS, % L SET M CV RREhp –0.16 mm

WS-4

SCS-2

SSV-6 SCS-3

SSV-5

SSV-8 SSV-7

R 0.483

To condenser To flanges and studs 130 554 361

R

kg/cm2 t/h CTD IS, % 39

17.1 R 73.2

HPH CTS

2

kg/cm °C t/h

SVB-1

SVB-2

SVB-3

IS, % 53.5

CTS LPH

R

5.58 0

Setting IB

To LPH-1 kg/cm2 t/h Z switched-off

SVMWH

SVB-4

SVB-5

SVB-6

SVHB

SSV-2

Live steam

CAS CPS CFS

HPH

LPH

Heating Fl. and Std.

Lubrication

Condenser

Gen. seals

Water heaters

Nomenclature

Fig. 4. CTS main operational technological scheme for PT-60-130 cogeneration turbine.

As an example, in Fig. 1, the structural scheme of the model of three units of the PT-60-130 cogeneration turbine is shown: a steam-admission system (SAS), a high-pressure cylinder (HPC), and a low-pressure cylinder (LPC). From the left side, input variables, i.e., live-steam pressure and the position of the cut-off and control devices, are inputted, while, from the right side, marked output variables are taken to which monitoring and automation instruments are connected. Technological units consist of modules and blocks. For example, HPC unit (Fig. 2) consists of three modules, each executing the same set of mathematical operations; four modules of dynamic transformations; and several typical blocks. Figure 3 shows a principal scheme of the dynamic transformations modulus. This scheme incorporates a dynamic member of the third order and a transport-lag link. The transport function of the modulus is as follows: for static objects, – τp

k ob e W ( p ) ob = -----------------------------------------------------------------------; 2 (T 1 p + 1)(T 2T 3 p + T 2 p + 1) THERMAL ENGINEERING

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for astatic objects, – τp

k ob e -. W ( p ) ob = -------------------------------------------------------2 T 1 p(T 2T 3 p + T 2 p + 1) All coefficients of the transfer functions are variable. This is necessary to provide the possibility of changing the dynamic characteristics, depending on the load and other factors. Time coefficients should be changed if the simulation time is changed. The main parts of the CTS are the operational-technological schemes (OTSs) of the controlled objects. An OTS is constructed at the computer display with the use of typical graphic elements that depict different pieces of technological equipment (cut-off and control devices, pumps, pulverizers, automatic controllers, measurement instruments, etc.). A special graphic element library is provided in the MEUS for this purpose. The possibility exists for animation of the graphic pictures for additional visual clarity of process representation. The CTS may consist of several operational-technological schemes, one of which is primary (Fig. 4) and from which any other scheme can be called up.

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For constructing an automated control scheme (ACS) of the technological processes, the MEUS contains special modules: an analog-type controller, which can imply P, PI, and PID principles of control; relayimpulse PI controller; differentiator; actuator, and so forth. By means of these modules, any ACS of the thermal power plant can be constructed. In the CTSs of the boiler and the turbine developed, automated control systems are made based on widely used and wellproven relay-impulse controllers. Control of the equipment is accomplished in situ or from control boards. All elements of the automated controllers (control unit, setter, instrument scale, and action indicator) are located in the OTS at a single location and act without a call. Each OTS is equipped with control and measurement instruments. Digital instruments are installed in the operational scheme at the points of the parameter measurements. Indicators with scales and alarm panels are located on the control boards. Recording instruments are called up from the points at which indicators are located.

In the training process, by means of CTSs, concrete technological operations are worked through that are commonly executed by personnel while setting up and carrying out different regimes: changing over from one kind of fuel to another, changing from one feedwater line to another, transition from the cogeneration mode of the turbine operation to the condensing one, switching on and off of the stand-by equipment, maintaining of the efficient regime of operation with the automation system being switched off, etc. These operations are included in department training courses and shift chiefs and operators of the power equipment of the TPP boiler and turbine departments. Local and regional competitions on the professional skill of the operational personnel of the Chelyabenergo and Uralenergo power stations are held based on the CTS. In conclusion, we should point out that the computerized training systems proposed are of interest not only to personnel training centers, but also to specialists that are immediately connected with servicing real objects. Relative simplicity, convenient operation, and the broad ability to simulate real processes make introducing this system very promising.

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No. 5

2006