Wu Enyuan, Liu Jing, Pei Shanyong, Zong Shousong
Wu Enyuan (Shandong Provincial Architectural Design and Research Institute, Jinan 250001)
Liu Jing (Jiangyin Kebo Architectural Design Institute Co., Ltd., Jiangyin City, Jiangsu Province 214400)
Pei Shanyong (Acrel Electric Co., Ltd., Shanghai 201801)
Zong Shousong (Jiangsu Ankerui Electric Manufacturing Co., Ltd., Jiangyin City, Jiangsu Province 214405)
Abstract : This paper introduces the basic principles, composition, functions and characteristics of fire equipment power supply monitoring systems, the design and installation of fire equipment power supply status monitors and fire equipment power supply sensors, and some precautions for their practical applications.
0 Introduction
With the rapid pace of urban construction in China, numerous high-rise buildings and large public buildings have sprung up. To ensure fire safety, a large number of fire-fighting equipment have been installed, such as fire hydrant systems, automatic sprinkler systems, foam extinguishing systems, smoke extraction systems, fire doors and roller shutter systems, fire elevators, emergency lighting, and evacuation guidance systems. When a fire occurs, the ability to extinguish it promptly, evacuate people quickly, and isolate the fire area largely depends on the proper functioning of this fire-fighting equipment. Therefore, the fire department of the Ministry of Public Security pays close attention to how to use technical means to achieve real-time monitoring of the power supply to fire-fighting equipment. Clause 5.3.14 of the mandatory national standard GB 25506-2010 "General Technical Requirements for Fire Control Rooms," which came into effect on July 1, 2011, stipulates that "the fire control room should be able to display the working status of the power supply and backup power supply of fire-fighting electrical equipment, as well as undervoltage alarm information." This, at the national standard level, mandates the installation of a fire equipment power supply monitoring system in the fire control room as an early warning system within the fire protection system. Another product standard for this system, GB 28184-2011 "Fire Equipment Power Supply Monitoring System", was also developed, providing a corresponding product testing basis for the fire equipment power supply monitoring system.
1. Introduction to Fire Equipment Power Supply Monitoring System
As an early warning and alarm system, the fire equipment power supply monitoring system mainly detects the relevant electrical parameters of the fire equipment power supply. When the power supply experiences faults or abnormalities such as overvoltage, undervoltage, overcurrent, phase loss, or phase reversal, and the relevant electrical parameters are not within the set value requirements, it should be able to issue an alarm signal and indicate the specific alarm location in the system. The alarm information should be recorded and saved for early maintenance, ensuring the reliability of the power supply to the fire equipment, and preventing the fire from being uncontrollable due to the inability of the fire equipment to function properly, thereby reducing fire losses.
The AFPM100 fire equipment power supply monitoring system is independently developed and manufactured by Acrel Electric Co., Ltd., and mainly consists of fire equipment power supply status monitors and sensors. This monitoring system was developed and designed by Acrel Electric Co., Ltd. based on the standard requirements of GB 25506-2010 "General Technical Requirements for Fire Control Rooms" and GB 28184-2011 "Fire Equipment Power Supply Monitoring System", combined with years of experience in electrical product design. This monitoring system features reliability, real-time performance, and the characteristics of digitalization, intelligence, networking, automation, and continuous monitoring. It reflects the power supply status of the monitored equipment in real time and displays it centrally, effectively preventing critical situations where fire equipment cannot function properly due to power failure during a fire, and maximizing the reliability of the fire-fighting linkage system.
1.1 Basic Principles
The AFPM100 fire equipment power supply monitoring system can monitor the power supply of fire equipment in real time. By detecting relevant information such as voltage, current, and switch status, it can determine whether there are faults in the power supply, such as open circuit, short circuit, overvoltage, undervoltage, phase loss, phase reversal, and overcurrent (overload), and alarm and record them. The monitoring system has an RS485 communication interface for data exchange with field voltage/current sensors; it adopts the Modbus-RTU communication protocol and can connect to other standard systems; through a user-friendly human-machine interface, it reflects the real-time status of the monitored equipment's power supply and displays it centrally.
1.2 Basic Components
The document "Fire Equipment Power Supply Monitoring System" defines and outlines the basic components of such a system. The AFPM100 fire equipment monitoring system consists of some or all of the following devices: a fire equipment power supply status monitor, voltage sensors, current sensors, and voltage/current sensors. The fire equipment power supply is either AC or DC, and includes a main power supply and a backup power supply.
The National Building Standard Design Atlas 10CX504, "Fire Equipment Power Supply Monitoring System," provides various system solutions suitable for different project sizes to achieve optimal results. These are generally divided into two categories: small-scale fire equipment power supply monitoring systems (as shown in Figure 1) and large-scale fire equipment power supply monitoring systems (as shown in Figure 2).
Figure 1 Topology diagram of power supply monitoring system for small fire-fighting equipment Figure 2 Topology diagram of power supply monitoring system for large fire-fighting equipment
1.3 Basic Functions and Features
Sensors are used to monitor and collect information on the power supply and operating status of various fire-fighting equipment in real time on-site. They also have event storage capabilities, allowing alarms to record the time, type, and parameters of alarms. Based on the alarm records, the on-site situation can be analyzed, providing a basis for troubleshooting. Furthermore, the sensors utilize fieldbus communication technology and host computer management software. They can monitor the on-site operation at all times and promptly detect alarm information. Through RS485 interfaces and the standard Modbus protocol, they can connect to various standard systems, offering advantages such as high integration, high networking and intelligence, and reasonable action characteristics. In practical applications, different sensors with different functions can be selected to meet the monitoring requirements of different fire-fighting equipment power supplies. The sensors are mainly divided into three categories: AFPM1 represents a single-phase power sensor, used to monitor AC/DC voltage and current; AFPM3 represents a three-phase power sensor, used to monitor the voltage and current of three-phase power supplies; and AFPM5 is an input/output sensor that can monitor switch status and can be connected to an alarm control loop. The modules adopt a standard modular design and are DIN rail mounted for convenient on-site use. A high-performance microcontroller is used to embed data acquisition and communication programs to achieve reliable data acquisition and transmission. Repeaters are suitable for systems where the distance between the monitor and the field sensor is long.
Repeaters not only increase the communication distance of the system but also power connected field sensors, solving the problem of communication signal and power output attenuation caused by long distances. The repeater transmits the power information of the connected field modules and the repeater itself to the monitor via a communication bus. The monitor centrally displays parameters such as the operating information, fault information, and location information of the fire-fighting equipment power supply, and provides audible and visual alarm signals when a power supply fault is detected.
2. Design and installation of fire equipment monitoring system
Article 3.1 of the "General Technical Requirements for Fire Control Rooms" states that "the fire-fighting equipment installed in the fire control room shall include fire alarm controllers, fire linkage controllers, fire control room graphic display devices, fire telephone switchboards, fire emergency broadcast control devices, fire emergency lighting and evacuation guidance system control devices, fire power supply monitors, etc., or combined equipment with corresponding functions."
The standard clearly states that a fire power supply monitor should be installed in the control room.
2.1 Design and installation of fire equipment power status monitor
The power status monitor for fire-fighting equipment (i.e., the system host) should be installed in the fire control room. In locations without a fire control room, the monitor should be installed in a manned location. For large buildings or building complexes, a combination of decentralized and centralized control methods should be adopted, that is, monitors should be installed in each fire control room or manned location to transmit the power status and alarm information of each fire-fighting equipment back to the central monitor in the control center for unified management, monitoring and display of information.
There are no specific standards specifying the installation requirements for monitoring devices. However, for fire protection monitoring systems, the relevant requirements for fire alarm controllers in GB 50116-2013 "Code for Design of Automatic Fire Alarm Systems" can be referenced.
2.2 Design and installation of power supply sensors for fire protection equipment
Currently, national standards do not explicitly specify the installation location of sensors. The "General Technical Requirements for Fire Control Rooms" only briefly mentions the need to monitor the operating status and fault alarm information of the power supply and backup power supply of various fire-fighting electrical equipment. The design of the entire system is largely in the hands of the designers.
Taking the "Technical Specification for Fire Equipment Power Supply Monitoring System in Shanxi Province" as an example, sensors should be installed in the following locations: the output terminals of the main power supply and distribution cabinets for fire equipment within the building; the dual power input and output terminals of fire electrical control devices (including pump controllers, fan controllers, etc.); the output terminals of the power supply devices (DC power supplies for each fire equipment) in each fire compartment; the output terminals of the distribution boxes supplying power to fire equipment; the input and output terminals of emergency power supplies for fire equipment; the output terminals of emergency lighting distribution boxes; the input and output terminals of dedicated emergency power supplies for centralized power supply type fire emergency lighting fixtures; and the input terminals of each main power supply circuit for equipment powered by multiple main power supplies. Currently, in most projects, monitoring all outgoing circuits of fire distribution boxes would result in very high project costs. Therefore, the placement of sensors should be carefully considered, and different types of sensors should be designed and installed for different fire-fighting electrical equipment.
Different sensors can be configured in the distribution box according to different fire-fighting equipment. For example, important fire-fighting equipment such as fire pumps, fire elevators, and smoke exhaust fans need comprehensive monitoring of voltage and current; systems that work for a short time in the early stage of a fire, such as fireproof roller shutters and emergency lighting, and loads that should not be overloaded or short-circuited, can only monitor the power supply, simplifying the system and reducing costs.
Below are some typical sensor design examples in fire protection equipment ( using Acrel Electric Co., Ltd. products as examples ):
a. Low-voltage power distribution system diagram for the fire pump room (as shown in Figure 3). At the incoming line, the dual power supply voltage is monitored using an AFPM3-2AV three-phase dual-voltage sensor. For the outgoing circuit, an AFPM3-AVI voltage and current sensor is recommended to comprehensively monitor the power supply and operating status of each fire pump.
Figure 3 Low-voltage power distribution system diagram for fire pump room
b. Fire protection power circuit power distribution system diagram, taking the fire exhaust and smoke extraction fan as an example (as shown in Figure 4). The power circuit detects the dual power supply voltage at the incoming line using an AFPM3-2AV three-phase dual voltage sensor. For the outgoing circuit, an AFPM3-AVI voltage and current sensor is recommended, allowing for comprehensive monitoring of the power supply and operating status of each fire protection power device.
Figure 4. Power distribution system diagram for fire ventilation and smoke extraction fans
c. Fireproof roller shutter and emergency lighting power distribution system diagram (as shown in Figure 5). The dual power supply voltage is detected at the power distribution box inlet using an AFPM3-2AV three-phase dual voltage sensor.
Figure 5. Fire shutter and emergency lighting power distribution system diagram
3. Precautions during installation and operation
a. When designing the sensor installation, the acquisition of voltage and current signals must not damage the circuit being monitored. Therefore, a 1A fuse should be connected in series with the phase line or positive terminal when acquiring voltage signals, and current signals should be acquired using a current transformer.
b. The power supply for the sensors must be provided by the fire equipment power monitoring system, i.e., by the monitor (or repeater), and cannot be obtained from other systems.
c. The distance between the sensor and the monitor (or repeater) should not exceed 500m. Wiring should avoid areas with high voltage and complex environments as much as possible. The power cable for the sensor should be a flame-retardant and fire-resistant twisted pair with a cross-sectional area of not less than 1.5mm² , and the communication cable should be a flame-retardant and fire-resistant twisted pair with a cross-sectional area of not less than 1.0mm². The cross-sectional area should meet both current strength and mechanical strength requirements. The selected cable should meet fire safety requirements, and shielded cables should be used where possible. Metal conduits should be used for wiring.
d. The total number of devices connected to each bus loop of the monitor (or repeater) should not be too large, and a margin of no less than 10% of the rated capacity of the loop should be reserved to facilitate future system expansion.
e. The AC power supply for the monitor (or repeater) should be a fire-fighting power supply.
4 Conclusion
This article mainly introduces the power monitoring system for fire protection equipment from the aspects of design and installation. Overall, the power monitoring system for fire protection equipment is still in its early stages, with related standards and applications relatively lacking. It is believed that as power monitoring system products for fire protection equipment are increasingly used in projects, these problems and shortcomings will be addressed and improved through standardization. As an early warning system, with its implementation, this system can improve the operational reliability of fire protection equipment, reduce unnecessary losses, and better safeguard social and economic development and the safety of people's lives and property.
Source: Building Electrical Engineering, Issue 9, 2014
References
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