Automatic Modeling of Fault Tree for NuIEEE Transactions on Power Electronics,Clear Power Safety I&C Configuration

doi:10.4236/epe.2013.54B052

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Energy and Power Engineering, 2013, 5, 269-273

doi:10.4236/epe.2013.54B052 Published Online July 2013 (http://www.scirp.org/journal/epe)

Automatic Modeling of Fault Tree for NuIEEE

Transactions on Power Electronics,Clear Power Safety

I&C Configuration

Shan Leng1, Bo Zhang1, We i Sun2, Zhiwu Guo2, Yichen Hao 1

1School of Energy and Environment, Southeast University, Nanjing, China

2Instrumentation and Control Institute, Guangdong Nuclear Power Engineering Corp. Shenzhen, China

Email: [email protected]

Received April, 2013

ABSTRACT

The automatic modeling of fault tree for nuclear power safety I&C configuration is designed to meet the requirements

of reducing the workload and improving the traceability during the nuclear power safety I&C system reliability assess-

ment work. To complete the fault tree automatic modeling, the Visio Automation software technology is used to ana-

lyze the topology of the nuclear power safety I&C system hardware device and software function. The good result in

practical implementations shows that the nuclear power safety I&C system fault tree modeling work is successfully

simplified.

Keywords: Nuclear Power Safety I&C System; Visio Automation; Automatic Modeling

1. Introduction

This paper takes nuclear power safety Instrumentation

and Control system, or I&C system for short, as the mod-

eling object. Safety I&C system, a crucial part of the nu-

clear power plant, guarantees safety, reliability and eco-

nomic efficiency. Considering the distinctive features of

nuclear power plant, safety and reliability of all nuclear

power systems must be verified with no exception of the

very important nuclear power safety I&C system. In or-

dinary verification modeling process, fault trees are built

manually after analyzing the topology of hardware and

the function of the software, which becomes not only

time-consuming, but also inconsistent with style, coding,

assumption and other factors. To make it worse, the er-

rors usually occur during the manual modeling process

gradually. Furthermore, today the whole process of the

fault tree modeling is required to be recorded for the

reason of simplicity and traceability, which makes man-

ual modeling workload of fault tree for nuclear safety

I&C system heavy and cumbersome. In order to solv e the

problems above, the automatic modeling methods need

to be conside red [1, 2, 7] .

In this paper, Visio Automation software technology is

used to analyze the topology of the nuclear power safety

I&C system hardware device and software function to

complete the fault tree automatic modeling work [6]. The

good result in practical implementations shows that the

nuclear power safety I&C system fault tree modeling

work is successfully simplified.

2. Automatic Modeling of Fault Tree

According to the designing concept of automatic model-

ing system of fault tree for nuclear power safety I&C

configuration, the structure of automatic modeling proc-

ess is shown in Figure 1. The new developed modeling

system is divided into three main parts: configuration

module stencils, configuration drawing and fault tree

automatic generation.

Figure 1. Structure of automatic modeling process.

S. LENG ET AL.

270

2.1. Stencils Design

In this paper, nuclear power safety I&C configuration

work require to create the Visio visualization stencils,

according to the respective characteristics of nuclear

power safety I&C system hardware device and software

function, ActiveX control technology is used to create

the card and logic ga tes module stencils for configur ation.

The created module stencils is shown in Table 1. User

can drag and drop the module in the stencils and draw the

signal line in the configuration diagram. After the nuclear

power safety I&C configuration diagram is completed,

User can use Visio Automation mechanism to get the

IDispatch scheduling interface of ActiveX control, the

control’s properties, methods and response control events

can be accessed. After analyzing the configuration dia-

grams, the automatic modeling system of fault tree will

lead anticipated results [8].

Table 1. Stencil mudule.

Type ActiveX control Description

I&C Card KLPJ Distribution module card

MRPJ Repeater card

PFBJ Intelligent I/O bus master card

PCPJ CPU card

MEOJ Optical conversion card

PSMJ System management card

PWNJ W-net network I/F card

MDOJ Digital output card

PPNJ System switchove r unit

Logic Gate 2/3 Two from three

2/4 Two from four

AND And gate

OR Or gate

Transmitter Level transmitter

Digital transmitter

Limiter Limiter

2.2. Configuration Object Feature

After configuration drawing is finished, a new Visio Au-

tomation program will be needed to analyze the con-

figuration diagram through the object model which con-

tains the attributes, methods, events and hierarchical re-

lationship between the objects. The Visio objects struc-

ture is shown in Figure 2. Built on the Visio Automation

programming resources, the topmost object acts as an

application object (Application). Through the Applica-

tion user can access to any other objects. User can use

the object’s properties and methods to perform certain

operations after obtain the object reference and identify

the features. According to the features of different ob-

jects, the objects can be classified as shown in Table 1.

Different types of objects must assigned different proper-

ties and methods.

2.3. Process of Automatic Modeling

In this paper, the automatic modelin g system of fault tree

for nuclear power safety I&C configuration is built b ased

on Visio Automation software technology. This technol-

ogy allows user to extend the visualization functionality

of Visio or make it as user program’s graphics engine.

User can not only create or modify the configuration di-

agrams based on external data, but also extract the rele-

vant configuration information from diagrams by a spe-

cial designed program [1]. In this paper, VC program-

ming language is used to write VSL library file [6], and

run in the way of sharing the same address space with the

graphics engine. This method has strong ability to inter-

act with configuration diagrams and high operating effi-

ciency.

The concept of control stream is used to analyze the

nuclear power safety I&C configuration diagram during

the automatic modeling processing. The fault courses and

results transfer in complex I&C configuration system

following the way of control streams. The configuration

diagram is analyzed based on control streams to organize

Figure 2. Visio objects structure.

S. LENG ET AL. 271

and classify the information modules. An analysis pro-

gram is designed to complete the automatic modeling

process.

1) User needs to co mplete the drawing work of device

configuration, user use the created module stencils and

signal line class to complete the configuration diagram.

After the completion of the diagram, assignment function

of the form class is used to complete the assignment of

the common cause group and module in configuration

diagram. According to the objects classification in Table

1, different types of objects must assigned different

properties and methods.

2) After the connection relation is checked, user can

analyze the configuration diagram. Visio Automation

software technology is used to get the object and its

properties and methods. The process of analysis is shown

as the automatic modeling part in Figure 1. At beginning,

the program gets the signal line, then the up- stream and

downstream information module is obtained. Then user

can analyze the feature of object to get the properties and

methods. After the analysis of the module and connection

relations and taking the failure mode into accoun t, a fault

tree file is generated.

3) User inputs the fault tree files through the interface

with Risk Spectrum, the nuclear power safety I&C sys-

tem configuration fault tree analysis work is completed.

3. Safety Configurations Implementation

In this paper, the automatic modeling method is used to

simplify the modeling work of fault tree for nuclear

power safety I&C configuration. The fault tree files are

generated follow the process of automatic modeling, the

structure of the process is shown in Figure 1. After the

fault tree is built, the correctness of automatic modeling

of fault tree must be verified. The implementation can be

divided into two typical parts: the measurement signals

configuration and channel group configuration. After the

implementation, the accuracy of automatic modeling

work is verified deeply and comprehensively.

3.1. Measurement Signals Configuration

The measurement signals configuration is very typical in

nuclear power safety I&C configuration system. Figure

3 shows the measurement signals configuration diagram.

This diagram has three LT transmitters, three KLPJ cards

and a logic gate. In order to complete this diagram, user

can drag and drop the module in the stencils and draw the

signal lines to connect modules. The completed diagram

is shown in Figure 3. The fault tree file is generated after

analysis of the configuration diagram. The created fault

tree is shown in Figure 4. In this figure, the Top Event

corresponds to the logic gate, a KLPJ card generates two

Basic Events and an OR Gate, the LT transmitter is in the

same situation with cards. The generated fault tree of the

measurement signals configuration is proven correct, that

means the accuracy of the automatic modeling work is

preliminary confirmed.

3.2. Channel Groups Configuration

The nuclear power safety I&C system has a lot of chan-

nels, the structur e of the channels are b asically the same.

Each channel is divided into A, B groups, the structure of

the two groups is identical. Th e intermediate portion of a

channel group A configuration diagram is shown in Fig-

ure 5. The signals of group A and B converges in PPNJ

cards. This channel groups configuration is very common

with the I&C configuration system.

The fault tree is generated after analyze the channel

groups configuration diagram. Because the overall fault

tree is too large, only part of the fault tree is shown in

Figure 6, this part is begin with the group A Limiter

cards and MEOJ cards ,through the set of K/N logic gates

the signal transmitted to the AND gate.

KLPJ

2/3

Figure 3. Measurement signals configuration diagram.

Figure 4. Fault tree of measurement signals.

S. LENG ET AL.

272

2/3 2/3

2/3

2/3 2/3

MRPJ

PFBJ

PCPJ

MEOJ

2/4

AND

PFBJ

PWNJ

MDOJ

PPNJ

PSMJ

MEOJ

Figure 5. Channel groups configuration diagram.

Figure 6. Fault tree of part of channel groups (a).

Figure 7 shows the fault tree which is begin with

AND output signal, through the PSMJ card and PWNJ

card, the PWNJ output signal merge with the signal of

group B to PPNJ card. The Top Event is the generated

gate by PPNJ card, the input signal is the AND gate. The

correctness of the automatic modeling system has been

verified comprehensively.

Figure 7. Fault tree of part of the channel groups (b).

4. Conclusions

In this paper, ActiveX control technology is used to cre-

ate the module stencil for configuration and VSL library

written in VC language is used as a tool to analyze nu-

clear power safety I&C system hardware device and

software function to build the fault tree. The successful

implementation of automatic modeling of fault tree has

verified the correctness of the automatically generated

fault tree. The method of the automatic modeling of fault

tree for nuclear power safety I&C configuration simpli-

fies the modeling work and improves the traceability of

the fault tree modeling. This method has been applied to

practical work, and with some modifications it can also

be applied to other systems such as the logic diagram

analysis of electrical system and information system.

Therefore, the method of fault tree au tomatic modeling is

bound to have broad application prospects.

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