monitoring of power plants

A DISTRIBUTED DATA BASE FOR REAL-TIME CONTROL/MONITORING OF POWER PLANTS J. B. Lewoc *, E. hsarska**

and A. Tomczyk**

*ZE Elwro, Wrocluw,P&?ld

Abstract.

Real-time monitoring and control of

MU or more power

a

power plant delivering 1000

is a complex task. It involves monitoring

of 10000 or so

analog signals and even more two-state signals. In addition, some data is to be interchanged between the real-time system

and the off-line ones which are

used by the power station staff involved in run preparation

functions.

The

paper describes the basic hardware and software tools designed for development of the distributed data base for a new power plant in Poland, which is a pilot implementation of such data bases.

Control

Keywords.

system,

management

system,

power

generation,

computer

network, performance bounds.

INTRODUCTION

The data base Bade1 (from Polish Baxa danych dla -_ elektrowni data base for power plants) should, invevitably, cover also the power plant dispatch

The Institute for Power System Automation (IASE). Wroclaw is involved in computerization

of

power

plants in Poland. The most complex project is progress

for

the

plant

power

monitor and the off-line service computer network

in

though

under

Opole

development. The power plant is to consist

of

PCU

which

configuration of

is

to

be,

the

power

plant

and the set of services to be

area

synchronized

control

turbine

"sequential"

being

design

of

provided

Bade1

for

the

with

the

power

network

is

of

our

systems RARDWARE ENVIRONMENT OF BADEL

including sequential controlles for PGU

are called here

are

country.

IASE (1986) develops the direct

switching on and off,

Bade1

phase 1 to be in operation when the first PCU

including the city of Opole.

for PM-s

of

The paper presents the logical

a

monitoring/protec-

environment

tion equipment vital for

fact,

in

components

6

power generating units (PCU), 360 MB each, plus a virtual

these

developed by other contractors.

controlles

which

controllers

(SC).

More complex tasks are performed by PGU which were, initially, intended for

The hardware environment is shown in Fig. 1.

monitors

PCU

The I-th PGU (14,. ..n) is equipped with 3s SC

control

-

type control systems which are implemented on the Raster

engineers'aids.

computers

(IASE

(198611based

on

Intel

8080A. The 1-th PCU's monitor is built on kl data After the very initial

phase of the project,

was recognized that it is worthwile and,

at

it

concentrators [DAQ) also

the

same time, feasible to develop a distributed data base for the

power

plant,

using

the

implemented

on

and two MERA 680 minicomputers (Meraster

Raster (198811

compatible with the Digital (1982) family LSL-11:

computer

the

systeem developed for individual purposes.

control

processor

(CP,)

presentation processor (PPll.

75

and

the

data

76

J. B. Lewoc, E. Slusarska and A. Tomczyk

n - number of PGUs = 7

DAQ

tp-

CP - control processor

PGU index

p = I....6 - actual

acquisition

data

computer

processor

PP - presentation

PGU-s

p - 7 - envoronment monitoring

POP BASE - power plant data base

equipment

POP CP - power plant control processor

SC - “sequential” control system I

I

-

i DO - local processing point

LPP

LPP - gateway to POP BASE NOVELLNET

POP

CONSOLE

---

Fig.1.

Power

The lower are

plant

level

micros

interconnected

operating,

automation

and

and the higher

level

via

primarily,

BS

232C

at the

management

(V.241

4.800

network

minis

system

links

problem

b/s

transfer

with

the

(Badel)

in our country. is

given

Some

elsewhere

discussion

(Bfach

of

this

(1989).

rate. DATA STRUCTURES ON THE LOWER LEVEL All

PW

monitors

680 computer Here,

in

front-end via

interconnected

the

BS 232C links

coxuamication

host

are

multiaccess are

used

subsystem

processor a direct

configuration.

too.

is

with

memory access

The basic

However,

provided

connected

MEBA

(DBA]

POP

shown in Fig.

a

The structures

are

held

of

of

a

BASE

channel.

any

filtered

value,

CP ; also (Arcnet

dispatch

run under

one working gateway

central

HERA 8801 and the Novell

station

(1986)

serving

area

NetWare

the

to POP BASE complete

(POP

processor

local

network 286)

functions

with a

of

the Bade1 hardware.

This

solutions

of

the

is

solutions

a poor LOGIC STRUCTDRE OF BADEL

-

the

basic

structure

data

retrieval

files,

data

functions

bottom to the designed

by which

in

practice.

from the to the a successful

interchange

will

top uay,

we

be

just The

here

protocols

described

in

as our solutions opposite

bottom has never

implementation

mean

of

abnormal

and

implies

the

overall

direction,

been resulted

in

a complex computer

primary

collect values

reproduced

excuse

throughput

for

the

on such

demand for

We consider

there

are

communication

conditions serious, performance

the

excuse

the

15% when all

information

and

the

worse, as

load

and archivation

In

solution

traffic

considerably

(CP)

unused while

‘economical’

unnecessary is

still

links

such complex plant

computer

transmission exceed

The

is

popular

computers

in general,

operation

in

- even for monitor

some

and current

not,

lower

value,

topology)

with

low level

subsystem.

in normal

the

were

PCU

one since:

passbands The logic

the

are

commmication

the

the variables

level. is

in

one value

(current

inconsistent

of

latter

the higher

in DAQ-s are

in RAM and only

variable

a bit

where

some history

maintained

2.

type

stored. The power plant

structures

the

with

the

data

a

PM.

implied

of

data is

sent

the by

does to

not the

77

KeaI-time Control/Monitoring

ANALOC: INPUT DATA

HIGHERLEVEL

OVERRIDECCJNT6OLS START OR RESTART

ACQUISITION CYCLE PI LTRATION

CONSTANS VALIDATION HISTEIlESES LIMITVALUES

CURRENT VALUE ------CURRENT STATUS

FILTERED VALUE ------CURRENT STATUS

EVENTAREA CHECKS -

4-J

al Analog data structures

TWO-STATE INPUT DATA

HIGHER LEVEL OVERRIDE CONTROLS START OR RESTART

PGU TOPOLOGY ~-+ I

I

CESI NG

k

INVER!lION & NEGATION

EVENTAREA ELI HINATION

bl Two-state data structures

Fig. 2. Basic data structures on the lower level

higher level in cycles

defined

by

the

THE TRAN!XISSIONPROTOCU WITHIN

process

THE PGUllONITORNETVORKS

control needs, - storing of current data on the higher results in much higher

fault

tolerance

failure sky be "hidden" due to the data

level (a

DAQ

kept

on

the higher level) of the whole system and CP be a source of "safety" data for every the

other

case,

delays may result

rather in

considerable

unsynchronisation

user;

may in

transfer in

the

case

of

the 360 MU monitor network.

Of the 7 layer level, model defined by IS0 (16621 for

the

Open

Systenm

,

Interconnection

physical layer, link layer and application are implemented in the monitor network The design

some data but used by varions users. The above premises were checked for the

General

criteria

for

the

efficiency (required

due

to

latter severe

the layer

protocal. were

the

throughput

limitations] and legibility needed to ensure easy

implementation,

and

Therefore, oriented

the

complex, like

1

FL

were

be

KEY:

1) FL - frame length in octets

DA

0 - 256 octets - 0 - FL octets i 21 DA = DESTINATION APPLICATION FL =

The

Layer SA

physical

protocal

232Cl.

defined

V.24

is

traverse

and

is

31 SA = SOURCE APPLICATION

COHWFtEP

The 4) CS = CBECKSUB

does

distinguish

of

(octets).

entities 6) COI4Fl=WHBAND APPLICATION

(FL1

REPLY

61 REP=

DATA Link

This

is

for:

distinguishing

transmission

called frames, - transmission data validation

realized

with

use of the longitudinal checksum which,

together

with

physical

the

parity

checks

of

the

cs

level,ensures that the error omission probability is not greater than ca. 2*10V5. - transport functions

consisting

the sender identity and, if

OK.

in

testing

delivering

Fig. 3. FRAME STRUCTURE

the

franxz to the application addressed, - flow control ensuring that the high nor level

computer

input

capacity

may

exceeded [we eliminate completely the octet

to

software

be

chance

to

delays),

the

requirements for data acquisition cycles are

met

miss any

due

low

never

and transmission delays for

random

(unfrequentl

frames are possibly low. For

the

above

flow

control

conxnand/reply

is

The corrmands and replies of the application layer are mutually aggreed between the lower and higher levels. Nevertheless, to

purposes,

we

use

the

frame

structure shown in Fig. 3. The

The Application Layer

representation

accomplished

field.

implemented the

The

with

the

protocol

is

function

rule of

such

a

us:

ensure

legibility,

that

each

well

defined

Send

we

corrmand is

a

application

topology.

Receive

preprocessing controls etc.

unsymmetrical in accordance with the requirements of automation applications and most commands issued by the high level. All commands need

are BASIC DATA STRUCTURES

some

ON TBE HIGHER LEVEL

answer. Till now, only one command is implemented on the low level: an event report substitutes any frame requested by a command; the is also a command to

ensure

report

itself for

acknowledgment

and DAQ-s of

one

monitor

are

divided

groups within which transmission is DAQ-s serving up to 192 and

a

transfer

rate

analog of

arrangement of the input system all

demands

performance.

on

variables

4800

SCS

into

serial.

4

For each,

b/s,

proper

ensures

meeting

communication

data

structures

subsystem

are

presented

in

Fig. 4. The kernel structure in this

the frame and thus reliable sensing of events.

For the power plant under consideration, all

These basic

data

base

is

the

process picture (PPl which is used to derive

all

nrajor files on the higher level. Let

us

mention

the history file which maintains the

movie

copy

of PP for some 30 minutes. If a major incident in the PCU happens,the movie copie may be dumped one of the pre-incident and

to

(30 qinuts after) to

the correspondent post-incident one for after the emergency is cleared).

analysis

Real-time

Control/Monitoring

79

PROCESS PICTURE

UWJIG

VARIABLES

FGU TOPDLOGY

ti PGU TOPOLOGY H&K

t 1 HOUR ’ -SHIFTLY

FILE

I-

COWPUTEZD ANALOG VARIABLES

COMPUTEDPGU MASK

MEAN VALUES OF ANALOG VARIABLES (LAST l4INUTEl

%

KISTORY FILE

r PRE-INCIDENT FILE

I POST-INCIDENT FILE

I \ TRACE FILE ‘_ (DISKS1

1 10s TRACE FILE + (RAM)

t I

I

AC

HERRING FILE (RAW

t

HERRING FILE ’ (DISKS) t

\ EVENT FILE (RAM1

ER

’

EVENT FILE (DISKS)

,

t 11 AC = Acquisition

KEY:

2)

Fig

The trace subsets it

is

(the

and herring of

easy traces -

Herrings

the

Basic

files

history

to follow are

4.

file courses

updated

in standard

ER=

data

are but

once per

structures

(in

a

arranged

of

on the higher

while

DATA RETRIEVAL SERVICES

that

variables

10 s

level

sense) so

SOM

acquisition

cycle

Event report

the

cycles).

The basic -

data

non-linear

files

incident too

are ones).

complex,

set-ions

of

cycle

character

The data

access

but

the

demands on data

application retrieval

of

the

-

are

not

schemes,

(except methods

puts services.

more

of

trends,

preparation plots

- preparation

services

processing

conversion

computation Disk

retrieval

individual

of

to

of

physical

integrating VDU

etc), of reports.

include: data

(such

etc),

pictures

as

values,

(tables,

To

speed

up

individually computer Rozent

preparation

defined

aided

design

(19881,which

base

enabling

edit

(not

required

for

Cadel

de

process

above, a

described

facto,

a

control

algorithm

individual

the

we have designed

system is,

to program) for

of

services

-

user

my

computer

defined

enable

us

engineers

to

and control

data

cases,

solution.

structure

to

apply

Each data

number (as

for

location

entity

the

lie.

is

data

data

but

picture)

file

model

effective

identified

process

the

the

simple

and

protocols

basing

within

So&

on that

remark should

and convert retrieval kept

them to the standard services

may be used

in any file

(this

tracing

scope

the software

of

the

and

its

electronic

mail

interconnect

the

for

the

prepared

Thus

ease the

any

on-line

on

also

- virtual LAN protocol

of

using

mostly

-

plant 680.

of

users) This

basic

is

can be the

data

the same

as for CF

was made services

base

POP-BASE

for

limited

data

for

in

retrieval

1 with

plant -

to on-line

decision

data

phase

POP-BASE (power -

of

HERA

that

the

the PCU monitors

services

software

power

PP:

order

for

developmnt

to get

access

Badel.

There

engineers over

a multi-user

system

to data

maintained

is

one limitation:

possess

any other

absolute

user

We assumed that

there

PCU roonitors’data feasible like

monitors

high

After

very

a

of LABS).

most

of all once

time resolution

Except

of

the

may be

(Lewoc

per is

area

- the

control

to their

data

staff).

we transfer file

files

are

minute.

PGU monitors,

task

all

is

communication

event

delivered

from

records

the while at

better

of

on demand only.

the users

of

an

is

the to

efficient

a working

of a gateway

and station

to POP-BASE.

(conversion

of

protocol),

level

functions.

section

of

upon request

us

to

of

our

clarify

the

our approach.

(not

Polish

actor,

we distinguish

alive),

the modern (innorative): better

than

the old

Jan

between something

to be called

Swiderski and

the

new

new

must

be

modern.

our approach

networks mainly

for

(eg.

networks

gave

2000 MU power

solutions

basing

protocol,

our

price,

Lewoc (1989))

to development The

power plants.

on sound and effective

on star ca.

and elsewhere

solution

for

solution

Comparing

is

basing

solutions

software

better

development

a

with

the

new

and

the

TOP

respect

to

on Proway networks

reliability

computer

approach

a feasible

plant,

of

we

with time,

etc.

not media

transmitted

Data

us

POP-BASE

Thus

it

should

statement proved.

be

called

And

collection

we

do

hope

here and

that

elsewhere

innovative

since

base

development

for for

it

gives

the power

this

-

above to

work

may

a complex

and

be -

a

solutions be

called verified computer

real-time

of

The

man-years

of many more or less obvious

described

systems

modern.

needed more than 150

industry.

(198911:

- any power plant local

whole

no need to reproduce

Thus,

other

the PCU

enables

functions

this

good

In the paper

any user

administration

speed

to POP-BASE all

the records the

is

the

priority

in PUP-BASE (the

without

those

(eg.

in

that

the

effort.

enabling

feasible)

assume

into

demanded

acpects

presented PUP-BASE is

not

base

all

and

reliable,

of

station/network

who

referees innorative

access

a of

to perform:

terminal

We have widened

enabling

the

architecture

LPP-o

is

to develop

FINAL BEMARKS AND CONCLUSION

TBE POP-BASE

The computer

to

to PUP-BASE/PCU monitor

transport

monitoring.

tool

service

a function

networks.

regards

network

LPP-s

LPP-0

the

within

a

We

configuration.

data

state

only

application.

Therefore,

instant

monitor)

for

entities

form. with

means that

the PCU may be analysed the

access

future

developed

the PCU monitor

multiuser

networking

serving procedures

the

being

development

its

record

are

single-program

makes

PC-s

useful

auxiliary

(the

general-purpose,

numbe+ 1.

Simple

to

be made with

286 is

by

the

access

the power industry.

Cormnunication

LAN. NetWare

of

a

of

by

knowledge

dedicated The well

having

network

user

having

network,

power plant

access

to

the

The bottonrup complex

dispatcher,

real-time

but

method

efficient applications

enables

distributed in

power

to

develop

data

base

plants.

a for The

l&xl-time

(:ontl-ol/Moliitol.i~i~

approach results in economic solutions and highly decreased chances of major design errors. The

solutions

discussed

here

are

organizational bases (standards) for of

distributed

data

Similar

industry.

bases

methods

for and

to

provide

development

Polish tools

power may

implemented in other applications (some

be

projects

are in progress).

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Blach

L.K.,

J.B.Leuoc,

Comparison

of

the

J.Mertz

top-down

(19891,

and

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and

Organization Design, IFIP, Berlin. Digital

PDP-11

(19821,

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(1982).

Open Systems Interconnection: Basic

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K.

Misiak,

A.

Tomczyk

(19891,

A

complex automation and nmnagement network for power plants, In Energy

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Management

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Microcomputers

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680,

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IASE

Functional no.

419

Xl