Xu Shuang
Ankerui Electric Co., Ltd., Shanghai Jiading 201801
1. Project Introduction
The new hospital building of a general hospital has a total construction area of ​​106,314.18m2. The total height above the ground is 99.4m, 26 floors above the ground, and 1 underground floor. In addition to an operating room on the first floor, second floor and fifth floor, the operating room has 9 out-patient operating rooms on the third floor, a total of 17 beds in the nerve ICU room, a total of 21 central operating rooms on the fourth floor, and 24 beds in the central ICU room. In this project, I will discuss the author's design in medical IT system applications.
2. Classification and power supply requirements of medical sites
According to "Electrical Installations of Buildings Part 7-710: Requirements for Medical Devices in Special Installations or Places" (GB16895.24-
The standards of 2005, IEC60364- 7- 710: 2002) classify medical rooms of different purposes into 0 sites, 1 sites, and 2 sites. The classification requirements are shown in Table 1.
Table 1 Categories and Levels of Safety Implementation in Medical Places
Among them, a category 0 medical site refers to a place where an electrical device that does not need to be in contact with a patient's body works. A type 1 medical site refers to a place where the contact parts of the medical electrical equipment need to work in contact with the electric apparatus of the patient's body surface and the body (other than the environment described in the category 2 medical site). The category 2 medical site refers to the place where the contact parts of the medical electrical equipment need to be in contact with the patient (mainly the heart or near the heart) and the electrical devices that endanger the life of the patient due to power interruption.
Type 2 sites must fully consider the danger of micro-shock and the importance of continuous power supply, and strictly limit the first-time fault current. Therefore, the “Civil Building Electrical Design Specification†(JGJ/T 16-2008) stipulates that in Category 2 sites The power circuits for life-sustaining, surgical, and other medical electrical devices and systems located within the "patient area" must be powered using isolated power (IT power). In Class 0 sites and Class 1 sites, the neutral point grounding system (TT/TN system) can be used to provide power because the power equipment is not in direct contact with the body's internal organs.
3, IT power distribution system in 2 types of medical applications
Type 2 medical sites have high requirements for continuity of power supply and leakage currents. The IT system reduces the leakage current from the system to the ground and the risk of electric shock to the human body is minimized. The installation of an insulation monitoring device in the IT system has greatly improved the accident prevention capability. Once the first insulation failure occurs in the system, it will not cause power outage of the system and ensure continuity of power supply.
In the hospital's operating room and ICU ward, in order to ensure the reliability of power supply, a dual-supply switching power supply method is used. Once the power supply is cut off, the other power supply will switch quickly. For important loads, IT systems are used for power supply. When an insulation fault occurs, the fault current will not form a loop to ground, and only a small capacitive leakage current will be generated. At the same time, the current will not cause the upper circuit breaker or fuse to operate, ensuring the continuity of the power supply. In order to monitor the insulation of the IT system to the ground in real time, an insulation monitoring device is set in the system. When the insulation of the system drops to the alarm value of the monitoring device, the monitoring device will issue an alarm message to indicate that the system has an insulation fault and must be eliminated as soon as possible. The IT system distribution diagram is shown in Figure 1.
Figure 1 Diagram of IT distribution system
In addition to using the IT system for power supply, this project also adopted the following measures to ensure the security and reliability of IT system power supply.
1) The circuit breakers used in IT systems are all equipped with short-circuit protection without overload protection circuit breakers to prevent tripping due to system overload and affect the continuity of power supply.
2) In order to effectively prevent electric shock accidents caused by the potential difference between the housings of different consumers, the system adopts reliable equipotential bonding.
3) The IT system socket and socket box have obvious signs, and the TN-S system plug cannot be inserted.
4) In order to minimize the leakage current caused by the leakage capacitance of the IT system to ground, the capacity of the isolation transformer is limited to less than 8 kVA.
5) The insulation monitoring of the IT system adopts a medical insulation monitor and meets the requirements of the national standard for such products. Insulation monitors are used only for fault alarms and cannot operate on circuit breakers.
4 Operating room IT power supply and insulation monitoring program
In this design, the operating room used Ankerui's medical IT power distribution products. The system consists of an isolation transformer, an insulation monitor, an instrument power supply, an external alarm display, and an insulation fault location device. Each operating room contains a set of IT systems. The IT system uses an 8kVA single-phase isolation transformer. Through the AIM-M200 insulation monitor, real-time monitoring of insulation resistance of the transformer secondary circuit to ground, secondary load current, and transformer temperature status can be realized. ASG100 signal generator and AIL100 insulation fault locating device were designed to realize the positioning function of insulation fault circuit. The alarm display device adopts AID200, which is connected with the AIM-M200 insulation monitor through the twisted-pair cable to display the data measured by the insulation monitor in the operating room and the monitoring room respectively. When a fault occurs, the site personnel are notified through the LED and the humming device. At the same time, through the output contact, the central control room staff on duty is notified to prepare for the fault. Each group of AIM-M200 insulation monitor is equipped with instrument-specific power supply DR-60-24, and the power output is DC24V. The composition of a single operating room system is shown in Figure 2.
Figure 2 IT distribution system diagram of operating room
In this program, the distribution of the operating room includes the IT system and the TN-S system. For the important equipment in the operating room, the power distribution is through the IT system, and insulation monitoring and fault location are implemented through the insulation monitor and fault locator. For equipment that is not important in the operating room, or if it is not in direct contact with the human body, the TN-S system is used to provide power, and a leakage protection circuit breaker no larger than 30 mA is used to prevent leakage safety accidents.
5 ICU Intensive Care Unit IT Power Supply and Insulation Monitoring Program
In the intensive care unit, the power distribution of the IT system is mainly to supply power to the nursing pendants of the monitoring beds. According to the demand of the load, 2 kVA of power is distributed for each pendant. In this design, each IT system uses an 8kVA single-phase isolation transformer, so it can meet the power requirements of 4 crane towers. Each IT system is equipped with one AIM-M200 insulation monitor, one set of insulation fault location device and one DC power supply. Since the Ankerui AID200 centralized alarm and display instrument can centrally monitor the insulation monitoring data of up to 16 IT systems, multiple sets of IT systems can share one set of AID200 centralized alarm and display devices, which are installed at the nurses' station to learn each other in real time. IT distribution system operating conditions. Figure 3 shows the distribution system diagram of the intensive care unit.
Figure 3 IT distribution system diagram in ICU room
5 Major Product Models and Configurations
With the wide application of electronic medical equipment in the hospital field, the threat of leakage currents to patients is also growing, especially in those places where life is at stake. Patients are directly inserted into the electrodes or sensors during surgery or anesthesia. In humans, small leakage currents may cause electrocution. Therefore, the electrical design for hospitals in this special place should be strictly in accordance with national standards and norms.
Ancorui's medical isolation power supply cabinet and its supporting insulation monitoring device are developed and designed for the power supply requirements of medical class II sites, and can well meet the safety and reliability of various types of operating rooms and intensive care units. Requirements, and in line with national standards.
Application
model
The main function
ICU/CCU Ward Isolation Power Cabinet
GGF-I series
Provides safe and reliable IT system isolated power supply for hospital ICU/CCU wards, and has an IT system insulation monitoring function.
Operating room isolation power cabinet
GGF-O series
Provides safe and perfect power supply solutions for various types of operating rooms in hospitals, provides safe and reliable IT system isolated power supply for important surgical equipment, and has an IT system insulation monitoring function.
Medical IT distribution system insulation monitoring device
AIM-M100
It has the functions of real-time monitoring of insulation resistance, isolation transformer load current, transformer winding temperature and fault alarming of the monitored IT system;
ACLP10-24
Instrument dedicated DC voltage regulator module, rail-mounted,
AID100
Insulation resistance, variable pressure load rate real-time display function; remotely set the alarm threshold of the insulation monitor
AKH-0.66P26
Protection type current transformer used with AIM-M100 insulation monitor. The maximum measurable current is 50A and the ratio is 2000:1
Isolation transformer
AITR series
Hospital-specific isolation transformers provide safe power isolation for various operating rooms and intensive care units
system integration
GGF-800 medical clean power monitoring system
Centralized monitoring and management of each insulation monitoring device so that when the monitored site is in trouble, relevant personnel can respond quickly and solve problems in a timely and effective manner.
With alarm display and recording function, according to the load current sub-warning and alarm, can record the alarm occurrence time, alarm type and alarm value and other information, and can support alarm sound (alarm sound can also be shielded), convenient operation and maintenance personnel analysis system operation Historical situation, timely troubleshooting
The monitoring screen of an IT power supply system can be called independently and the detailed status of the transformer operation can be queried by manually selecting the IT power supply system.
The system has a map and on-site distribution map display function to facilitate timely and intuitive detection of the alarm location or area of ​​the IT power supply system
7 Equipment List
8KVA Embedded Operating Room Isolated Power Cabinet (GGF-O8QL) Equipment Details
No.
name
model
Quantity
unit of measurement
1
Insulation monitor
Acrel AIM-M200
1
only
2
Isolation transformer
Ankerui AITR8000
1
only
3
Alarm and display
Ankerui AID200
1
only
4
Instrument power supply
Ankerui DR-60-24
1
only
5
Signal generator
Ankerui ASG100
1
only
6
Fault locator
Acrel AIL100-8
1
only
7
Fault locator
Ankerui AIL100-4
1
only
8
Current Transformer
Acry AKH-0.66P26
1
only
Acry AKH-0.66 40I 100/5
3
only
9
Cabinet
Operating room embedded GGF-OXQ
1
only
10
Isolation switch
Schneider INS80 4P
1
only
11
breaker
Schneider iC65N-C20/4P
1
only
Schneider iC65N-C20A/4P+Vigi ELE A 30mA
1
only
Schneider iDPNN-C16A/1P+N+Vigi ELE A 30mA
3
only
Schneider iC65N-C10/1P
5
only
Schneider iC60LMA-C40/2P
2
only
Schneider iC60LMA-C25/2P
8
only
12
Meter
Ankerui DTSF1352
1
only
13
PE terminal block
B-3X17/10
2
only
14
Terminals
For GGF
2
set
15
Signal light
AD11-22/21-5GZ AC220V Green
2
only
AD11-16/41-6GZ AC220V Red
17
only
16
Surge protector
Schneider iPR 20 3P+N
1
only
17
heat sink
KA1238HA2BMT
2
only
18
Accessories
GGF-O8/10G
1
item
8KVA Embedded ICU Room Isolated Power Cabinet (GGF-I8QL) Equipment Details
No.
name
model
Quantity
unit of measurement
1
Insulation monitor
Acrel AIM-M200
1
only
2
Isolation transformer
Ankerui AITR8000
1
only
3
Alarm and display
Ankerui AID200
1
only
4
Instrument power supply
Ankerui DR-60-24
1
only
5
Signal generator
Ankerui ASG100
1
only
6
Fault locator
Ankerui AIL100-4
1
only
7
Current Transformer
Acry AKH-0.66P26
1
only
8
breaker
iC60LMA 2P 40A
1
only
9
iC60LMA 2P 16A
4
only
10
Cabinet
ICU Room Embedded GGF-IXQ
1
only
11
PE terminal block
B-3X17/10
2
only
12
heat sink
KA1238HA2BMT
2
only
Reference paper:
[1] Application of Medical IT System in Class 2 Hospital Sites. Building Electrical 2006.4
[2] Ancorui Electric Co., Ltd. Product Selection Guide 2013.1.
About the Author:
Xu Shuang, female, undergraduate, Ankerui Electric Co., Ltd., the main research direction for medical power distribution design, mobile phone QQ
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