Ankerui Qingqing

Jiangsu Ankerui Electric Appliance Manufacturing Co., Ltd. Jiangyin, Jiangsu 214405

Abstract: This article briefly describes the composition principle of electrical fire monitoring system, and analyzes the design basis and related specifications of electrical fire monitoring system in application. Finally, through the example of the Ankerui residual current type electric fire monitoring system in the Outpatient Complex Building Project of the First People’s Hospital of Baiyin City, the realization of the function of the electric fire monitoring system and its significance are described.

Key words: electrical fire; residual current electrical fire monitoring detector; monitoring system; Acrel-6000/B; Baiyin First People's Hospital.

0 Overview

The First People’s Hospital of Baiyin City is the hospital with the strongest technical strength, the widest range of services, the most sophisticated inspection equipment, and the most comprehensive service items in the Silver Region. It is the only hospital in the region that provides medical, teaching, scientific research, preventive health care, and occupational health checks. City-level general hospital that integrates diagnosis and maternal and child health care technologies. This project is part of the electrical fire system at the substation of the First People’s Hospital of Baiyin City, and the ARCM200BL-J4 residual current fire detectors are located at the outpatient building complex of the First People’s Hospital of Baiyin City and installed in substations. cabinet. The on-site fire detectors are bus-connected to the Acrel-6000/B wall mounted electrical fire monitoring system. This system has the advantages of convenient installation and transportation, high cost performance, and easy maintenance.

1 Reference standard

In recent years, the state has successively formulated or revised a number of relevant standards and regulations to strengthen the prevention of electrical fires in order to increase the prevention of electrical fire monitoring. There are:

(1). It is GB50045-95 (2005 edition) "High-rise Civil Building Design Fire Prevention Code", which states in Article 9.5.1 that high-rise building fire risk, personnel intensive and other places should be set up a leakage fire alarm system.

(2). It is GB50016-2006 "Building Design Fire Protection Code". It is stipulated in Clause 11.2.7 that the following places should be equipped with residual current action electrical fire monitoring system. These venues include various types of theaters, halls, warehouses, residential quarters, hospitals, shops, schools, and so on.

(3). The relevant provisions of the national standard “Building Electrical Fire Prevention Requirements and Testing Methods” also explicitly require that “the residual current protection device that automatically cuts off the power supply or alarm should be installed at the power supply inlet”.

(4). Electrical fire monitoring system products should meet: GB14287.1-2005 "Electrical fire monitoring equipment", GB14287.2-2005 "residual current electrical fire monitoring detector", GB14287.3-2005 "temperature-type electrical fire monitoring and detection Device

(5). The installation and operation of electrical fire monitoring system shall meet GB13955-2005 "Installation and Operation of Residual Current Operation Protection Device"

(6). The power supply of the electrical fire monitoring system shall meet the requirements of GB50052 "Design Specification for Power Supply and Distribution System"

(7). The design of electrical fire monitoring system should meet the requirements of "Design Method for Electrical Fire Monitoring System" (Interim Provisions)

2 system components

According to the national standard GB14287-2005 "Electrical Fire Monitoring System" and related specifications "Design method of electrical fire monitoring system" (provisional regulations), the basic composition of electrical fire monitoring system should include: electrical fire monitoring equipment, residual current electrical fire Monitoring detectors and temperature-detection type electrical fire monitoring detectors are composed of the three most basic product categories.

The residual current type electric fire monitoring system adopts a hierarchical distributed structure and is composed of a station control layer, a network communication layer, and a field device layer. All electrical fire monitoring probes are connected to the communication server through a shielded twisted pair RS485 interface, using a MODBUS communication protocol bus type connection, and then enter the industrial switch through the Category 5 TCP/TP protocol, and then reach the monitoring host through the optical cable.

System network structure

1) Station control management

Station management The management personnel of the electrical fire monitoring system are the direct windows of human-computer interaction and the top part of the system. Mainly by the system software and necessary hardware devices, such as touch screen, UPS power supply and other components. The monitoring system software calculates, analyzes, and processes various types of data on the site, and responds to the on-site operations by means of graphics, digital display, sound, and indicator lights.

Monitoring host: used for data acquisition, processing and data forwarding. Provides data interfaces within or outside the system for system management, maintenance, and analysis.

UPS: Ensure the normal power supply of the computer monitoring system. When the power supply problem occurs in the entire system, ensure the normal operation of the station control and management equipment.

The background monitoring equipment is set in the control center.
2) Network communication layer

Communication medium: The system mainly adopts shielded twisted pair, uses RS485 interface and MODBUS communication protocol to realize real-time communication between field device and host computer.

3) Field device layer

The field device layer is a data acquisition terminal, mainly ARCM200BL-J4 remaining electrical fire monitoring detector. The ARCM200 residual current type electric fire monitoring detector is designed for TT and TN systems below 0.4kV. It monitors and manages the fire hazard parameters such as residual current, wire temperature, overcurrent, and overvoltage in the distribution circuit. This prevents the occurrence of electrical fires. Products using advanced microcontroller technology, high degree of integration, compact size, easy installation, intelligent, digital, network in one, is the building electrical fire prevention and control, insulation insulation system, such as the ideal choice. The product complies with the standard requirements of GB14287.2-2005 "Electrical fire monitoring system Part 2: Residual current electrical fire monitoring detector".

The distributed I/O controller connected to the fieldbus forms a data acquisition terminal and uploads the collected data to the data center. The measuring probes are responsible for the most basic data collection tasks. The data they monitor must be complete, accurate and transmitted to the monitoring host in real time. It facilitates the operation personnel to monitor the status of field equipment operation, fault alarms, etc. to effectively prevent the occurrence of fire accidents.

3 system characteristics and working principle

The characteristics of the electrical fire monitoring system are that the residual current monitoring is an early warning system. Unlike traditional fire automatic alarm systems, early warning of electrical fire monitoring systems is to avoid losses, while traditional fire automatic alarm systems are used to reduce losses. Therefore, this means that no matter whether it is a new or reconstructed project, especially a unit that has already installed an automatic fire alarm system, it still needs to install the root cause of the electrical fire monitoring system.

The electrical fire monitoring system measures the two physical quantities of residual current and temperature.

Residual current measurement is based on Kirchhoff's current law: At the same time, the vector of the current flowing into and out of a node in the circuit is zero. Taking the TN-S system as an example, the A/B/C/N is passed through the residual current transformer at the same time. When the system is not leaking, the current vector flowing into and out of the residual current transformer is zero, and at this time, the residual current The secondary current induced by the transformer is also zero; when a leakage occurs on a relatively large ground, the current vector at the time of flowing into and out of the residual current transformer is no longer zero, and its magnitude is equal to the current flowing from the ground, ie the leakage current. The leakage signal is transmitted to the electrical fire detector through the secondary wiring of the residual current transformer, and is transmitted to the CPU after operation amplification and A/D conversion. After a series of algorithms, the amplitude of the change is analyzed, judged, and The alarm set value is compared. If the value exceeds the set value, an audible and visual alarm signal is sent and sent to the back-end electrical fire monitoring equipment.

The temperature measurement uses a temperature sensor, which is generally measured using a Pt100 sensor. This type of temperature sensor has a stable temperature measurement range and a large measuring range. It is suitable for on-site monitoring of cable temperature and ambient temperature. When the temperature changes, the resistance of Pt100 changes with the same proportion. The resistance signal is transmitted to the electrical fire detector. After a series of signal transformation and calculation, the final result is compared with the temperature alarm setting value. If the value exceeds the fixed value, An audible and visual alarm signal is then sent and sent to the back-end electrical fire monitoring equipment.

4 configuration of system parameters

4.1 Setting range of alarm value

According to the provisions of the national standard GB14287.2-2005, the alarm value of the residual current type electrical fire monitoring detector is set in the range of 20~1000mA. According to this requirement, the residual current operating value at the total power supply line is generally set to 400~800mA, and the residual current operating value on the power branch line is set to 100~400mA. Generally, the residual current type electric fire monitoring and detection is set at the actual site. The alarm value of the device, in concrete terms, should not be less than 2 times the maximum value of the leakage current during normal operation of the protected electrical line and equipment, and not more than 1000 mA. Electrical fire detectors' alarm settings should take into account the normal leakage currents of the distribution system and electrical equipment.

4.2 About the cable temperature rise alarm setting reference, according to the "Power Cable Design Code" on the cable temperature requirements

(1) High temperatures above 60°C should be selected according to the high temperature, duration, and type of insulation. Heat resistant PVC, XLPE, or EP rubber insulation, etc. should be selected. High temperature above 100°C. Insulated cable. High-temperature places should not use ordinary PVC insulated cables.

(2) The ambient temperature of the cable that allows constant current carrying capacity shall be determined according to the average of the meteorological temperatures in the area in use for many years, and shall comply with the regulations. When laying the cable trench in the house, the ambient temperature is the average of the highest daily temperature in the hottest month of the site plus 5°C.

(3) The temperature rise of the cable is related to laying and heat dissipation conditions.

5 System Introduction

Acrel-6000 electrical fire monitoring system is an independent research and development by the company to receive the residual current electrical fire detectors and other field equipment signals to achieve the alarm, monitoring, control and management of the protected electrical circuit running on the computer's industrial level Hardware/software system. The system is applied to fire control centers in large shopping malls, living quarters, production bases, office buildings, shopping malls and hotels, and remotely measures, remotely adjusts, remotely controls, and remotely detects the detectors scattered in buildings to facilitate monitoring and management. The system uses a standard Modbus field bus to connect detectors with communication functions. When the detected parameters in the field protection circuit exceed the alarm setting value, it can send alarm signals, control signals, can indicate the alarm location and save the alarm. information.

The main technical parameters

(1). Power:

1 rated working voltage AC220V (-15% ~ +10%)

2 Standby power supply: When the main power supply is undervoltage or power failure, maintain the monitoring equipment working time ≥ 4 hours

(2). Work system:

24-hour work

(3). Communication method:

RS485 bus communication, Modbus-RTU communication protocol, transmission distance 1km, can extend communication transmission distance through repeater

(4).Monitoring capacity:

1 Monitoring equipment can monitor up to 200 monitoring units (detectors)

2 can be connected with ARCM series monitoring detector

(5). Monitoring alarm items:

1 Residual current fault (leakage): Fault cell attributes (position, type)

2 Temperature alarm (over temperature): Fault cell attributes (part, type)

3 Current fault (overcurrent): Fault cell attributes (part, type)

Monitoring alarm response time: ≤30s

Monitoring alarm sound pressure level (A weighting): ≥70dB/1m

Monitoring alarm light display: red LED indicator, red light alarm signal should be maintained until manual reset

Monitoring alarm sound signal: Can be eliminated manually, when it is alarm signal input again, it can start again

(6) Failure alarm items:

1 An open circuit or short circuit occurred in the communication cable between the monitoring equipment and the detector

2 Monitoring equipment main power supply undervoltage or power failure

3 An open circuit or short circuit occurred in the connection between the battery charger and the battery

Fault alarm response time: ≤100s

Monitoring alarm sound pressure level (A weighting): ≥70dB/1m

Monitoring alarm light display: yellow LED indicator, yellow light alarm signal should be maintained until troubleshooting

Fault alarm sound signal: can be eliminated manually, when it is alarm signal input again, it can start again

During faults, normal operation of non-failed circuits is not affected

(7). Control output:

Alarm control output: 1 set of normally open passive contacts, capacity: AC250V 3A or DC30V 3A

(8). Self-inspection project:

1 Indicator Check: Alarm, Fault, Operation, Main Power, Standby Power Indicator

2 display check

3 audio device inspection

Self-check time ≤60s

(9). Event record:

1 Record content: record type, occurrence time, detector number, area, fault description, no less than 20,000 records can be stored

2 record query: according to the record of the date, type and other conditions

(10). Operation classification:

1 daily shift: real-time status monitoring, event record query

2 monitoring operation level: real-time status monitoring, event record query, remote reset of the detector, device self-test

3 System management level: real-time status monitoring, event record query, remote reset of detector, device self-check, system parameter query of monitoring equipment, individual detection of each module of monitoring equipment, operator addition and deletion

(11). Use of environmental conditions:

1 Workplace: fire control room, manned power distribution (distribution room), on-call room walls

2 working environment temperature: 0 °C ~ 40 °C

3 working environment relative humidity: 5% to 95% RH

4 Altitude: ≤2500m

basic skills

(1).Monitor alarm function:

The monitoring equipment can receive the leakage and temperature information of multiple detectors. When the alarm sounds, an audible and visual alarm signal is emitted. At the same time, the red “alarm” indicator light on the equipment is on. The display indicates the alarm location and the type of alarm. The alarm time is recorded and the sound and light alarm is maintained. , until the display reset button remote reset the detector. The audible alarm signal can also be manually cancelled using the display “Mute” button.

(2). Fault alarm function:

Communication failure alarm: When a communication failure occurs between the monitoring device and any of the connected detectors, the corresponding detector in the monitoring screen displays a fault prompt, and the yellow “fault” indicator on the device lights up, and a fault alarm sounds. .

Power failure alarm: When the main power supply or standby power supply fails, the monitoring device also emits audible and visual alarm signals and displays the fault information. You can enter the corresponding interface to view detailed information and cancel the alarm sound.

(3). Self-test function:

Check if all the status indicators, display screens and speakers in the device are normal.

(4). Alarm record storage query function:

When leakage, over temperature alarm, or communication or power failure occurs, the alarm location, fault information, alarm time and other information are stored in the database. When the alarm is released and the fault is eliminated, it is also recorded. Historical data provides a variety of convenient and fast methods for searching.

(5). Power function:

When the main power supply has a power failure or undervoltage, the monitoring device can automatically switch to the standby power supply. When the main power supply resumes normal power supply, it automatically switches back to the main power supply, ensuring that the monitoring device runs continuously and smoothly during the switchover process.

(6). For detector control functions:

By monitoring the software operation, remote reset control can be performed on all detectors connected to the device.

(7). Authority control function:

In order to ensure the safe operation of the monitoring system, the monitoring device software operating authority is divided into three levels, and different levels of operators have different operating rights.

Since the system was put into operation, it has performed well and has played an important role in preventing electrical fires. It has obtained the recognition and trust of customers for products and companies.

references

[1]. Ren Chengcheng, Zhou Zhong. Principles and Application Guide for Digital Meters for Electric Power Measurement [M]. Beijing. China Electric Power Press, 2007. 4

[2].Zhou Zhong. Application of Power Meters in Energy Metering of Large-scale Public Buildings [J]. Modern Building Electronics 2010. 6

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