• Proceedings of the Korean Nuclear Society Conference
• /
• 1995.10a
• /
• pp.185-190
• /
• 1995

Conventional alarm system has many difficulties in the operator's identifying the plant status during special situations such as design basis accidents. To solve the shortcomings, an on-line alarm annunciator system, called dynamic alarm console (DAC), was developed. In the DAC, a signal is generated as alarm by the use of an adaptive setpoint check strategy based on operating mode, and time delay technique is used not to generate nuisance alarms. After alarm generation, if activated alarm is a level precursor alarm or a consequencial alarm, it would be suppressed, and the residual alarms go through dynamic prioritization which provide the alarms with pertinent priorities to the current operating mode. Dynamic prioritization is achieved by going through the system- and mode-oriented prioritization. The DAC has the alarm hierarchical structure based on the physical and functional importance of alarms. Therefore the operator can perceive alarm impacts on the safety or performance of the plant with the alarm propagation from equipment level to plant functional level. In order to provide the operator with the most possible cause of the event and quick cognition of the plant status even without recognizing the individual alarms, reactor trip status tree (RTST) was developed. The DAC and the RTST have been simulated with on-line data obtained from the full-scope simulator for several abnormal cases. The results indicated that the system can provide the operator with useful and compact information fur the earlier termination and mitigation of an abnormal state.

• Journal of the Korean Society of Safety
• /
• v.37 no.2
• /
• pp.69-75
• /
• 2022

Fire-alarm systems are safety equipment that facilitate rapid evacuation and early suppression in case of fire. It is highly desirable that fire-alarm systems have low false-alarm rates and are thus reliable. Until now, researchers have attempted to improve detector performance by applying new technologies such as IoT. To this end, IoT-based fire-detection systems have been developed. However, due to scarcity of large-scale operational data, researchers have barely studied malfunctioning in fire-alarm systems or attempted to reduce false-alarm rates in these systems. In this study, we analyzed false-alarm rates of smoke/temperature detectors and unwanted fire-alarm signal patterns at K institution, where Korea's largest IoT-based fire-detection system operates. After analyzing the fire alarm occurrences at the institution for five years, we inferred that the IoT-based fire-detection system showed lower false-alarm rates compared to the automatic fire-detection equipment. We analyzed the detection pattern by dividing it into two parts: normal operation and unwanted fire alarms. When a specific signal pattern was filtered out, the false-alarm rate was reduced to 66.9% in the smoke detector and to 46.9% in the temperature detector.

• Journal of the Korean Society of Safety
• /
• v.37 no.5
• /
• pp.14-21
• /
• 2022

The purpose of this study was to apply the signal pattern recognition technique to the digital wireless fire-alarm system and to reduce unwanted fire alarms. In this study, the fire alarms of the K Institute, which operates the largest digital wireless fire-alarm system in Korea, were classified into normal operations and unwanted fire alarms, and these were analyzed and compared with actual fire signals. In addition, by designing a non-fire signal filter and applying it to the K Institute, we confirmed that the monthly unwanted fire alarm rate of all 5,713 detectors decreased sharply. In particular, the unwanted fire alarm rate for flame decreased from 1.09% to 0.11% and the unwanted fire alarm rate for smoke decreased from 0.65% to 0.035%.

• Korean Security Journal
• /
• no.8
• /
• pp.197-218
• /
• 2004

This study has been conducted to provide data that contribute to increasing efficiency of 'Private Security', which is cooperated by customer, security companies and the police which carried out 'Public Law Enforcement' and controls security companies. To reach this purpose, we investigated the status of the 'Security Alarm Systems' operated by security service companied in Korea, analyzed arising problems, considered the polices for improving the operational quality. 'Electronic Security Systems' will increase working efficiency in performing 'Private Security'. There can be no two opinions on this matter. Therefore, it can be supposed that the improvement of operational quality of 'Electronic Security System' is an important factor to accomplish security services. 'Security Alarm System' is one of the 'Electronic Security System'. The critical problems in operating 'Security Alarm system' are unnecessary response by false alarm and nuisance alarm. To reduce the problems, it is suggested that security specialist officially licensed should improve security planning, installation and maintenance, and the 'Alarm Verification System' should be introduced with appropriate facilities.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.10
• /
• pp.1804-1810
• /
• 2011

It is necessary to adopt some logical techniques and methods of alarm processing for a large complex plant such as nuclear power plants in order to present the occurred alarm messages properly and concisely. Among such alarm processing techniques, the alarm suppressing function is a strong tool to avoid alarm flooding during the sudden transients of plant output power such as turbine trips, reactor trips and other incidents. Unless any suppression or representation technologies are used in an alarm message listing system, it cannot provide quick assistance to plant operators or supervisors during plant upsets because too many alarm messages are presented in an alarm list window. This paper presents the key suppression methods and analysis processes developed for implementing a suppressed alarm message listing function of an integrated alarm system called LogACTs which has been applied to a CANDU nuclear power plant. A simulation testing of the suppressing function conducted with the real plant alarm message list data has demonstrated an effective performance of the developed logics with the high suppression rate.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.32B no.8
• /
• pp.1045-1056
• /
• 1995

The purpose of multiple alarm processing is to give the operator the correct information and perception of the malfunction present in the plant. In this thesis, an APS(Alarm Processing System) is studied for fossil power plants. This APS is based on a cause-consequence trees in the knowledge representation aspect for alarm and plant and adapts alarm filtering methods using fired time information in the decision aspect. Through the cause-consequence trees and filtering methods, the Alarm Processing System finds the cause alarm among the fired multiple alarms and calculates the cause degree which represents the possibility of a fault occurring in the instruments of the plant with the information of fired alarm. The knowledge base is built via interviews and questionaries with the expert operators on the Seoul power plant unit 4. Finally, the validity of the studied APS is shown via simulations.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 1997.11a
• /
• pp.633-640
• /
• 1997

Type R fire alarm is required intelligent buildings and height buildings which was based on automatic system. But in Korea, maintenance of fire alarm system is very poor. In this study, we developed assessment model for the type R fire alarm system which was assessed by using 96 checklist items. The assessment model was tested through the actual 4 buildings with type R fire alarm system. It is shown that present model can be applied for the assessment of all buildings through the examination of the suitability of assessment model by actual assessment. Also, it was made easily fire manager to carry out checklist for type R fire alarm system in buildings.

• The Journal of the Korea Contents Association
• /
• v.10 no.11
• /
• pp.341-351
• /
• 2010

Alarm system is very important for the safety of nuclear power plant. When alarm, operator refers alarm logic diagrams to identify the logical relationship between the alarm and its causes. This paper propose a system which tracks the logical path between alarm and its causes on the alarm logic diagrams of Wolsung nuclear power plant unit 3 & 4. And a grammar for the validation of logic diagrams expressed in 2 dimensional strings, and logical operations with 3 states to track alarm-cause paths and to display the state of logics are proposed. This system is on operation at Wolsung site.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05a
• /
• pp.133-138
• /
• 1997

For a long time, a number of alarm processing techniques have been researched to reduce the number of actuated alarms for operators to deal with effectively during the abnormal as well as the normal conditions. However, the strategy that the only systems with a few clear technologies should be used as a part of an alarm annunciation system has been adopted considering the effectiveness and the reliability in actual alarm processing systems. Therefore, alarm processing systems have difficult knowledge-base maintenance problems and limited expansion or enhancement defects. To solve these shortcomings, the integrated knowledge-base which can express the general information related to all the alarm processing techniques is proposed and its management tool, Knowledge Input Tool for Alarm (KIT-A) which can handle the data of the knowledge-base efficiently is developed. Since the integrated knowledge-base with KIT-A can manipulate all the alarm information without the modification of alarm processing system itself, it is expected to considerably advance the overall capability of maintenance and enhancement of the alarm processing systems.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.1272-1277
• /
• 2004

GPS type portable-alarm-system is composed of satellite receiving equipment, signal transmission equipment, etc. Time errors occur because of the processing methods of the satellite receiving equipment and signal generator, the positional error of GPS itself, etc. With the recent rise of train speed, it becomes very important to secure the stability of portable-alarm-system from time errors, The present study estimated errors caused by the structure of portable-alarm-system, GPS errors. etc., and verified them. In addition, it examined the effects of such errors on portable-alarm-system according to train speed.