Technical reference · English
Data center power system power supply status
DATACENTRE POWER SUPPLY SYSTEM OVERVIEW
This article discusses the insulation monitoring solution for the ungrounded power supply system of the data center. Power transmission mainly relies on transmission cables. However, because data centers have high requirements for power supply continuity and the power supply environment is complex, single-phase leakage or single-phase ground faults may occur in cable lines, which may increase the risk of electric shock, cause equipment damage, or even shut down the entire system. Therefore, here we consider using mature electrical insulation online monitoring technology to improve the safety and reliability of DC power supply in data centers.
Online insulation monitoring of ungrounded systems observes the system's insulation to ground by measuring signals. With the fault locating device and branch circuit transformer, the abnormal circuit can be further identified. Monitoring, positioning and protection actions should be configured separately according to the system design.
The corresponding monitoring device applies measurement signals to the system under test and obtains insulation information through the measurement loop. System voltage, distributed capacitance, load and interference conditions influence device selection. Alarm and branch circuit information can help operators narrow the scope of inspection and carry out maintenance based on on-site conditions.
INSULATION MONITORING DEVICE
The measurement signal and response characteristics of the insulation monitoring device should be suitable for the AC, DC or hybrid system under test. The adaptive measurement capability, allowed system distributed capacitance and applicable range are subject to the technical information of the corresponding model.
INSULATION FAULT LOCATION SYSTEM
According to the actual use on site, we can have the following system monitoring diagram 2. When the insulation monitor ATK-IMS200 alarms, the corresponding monitoring module can send out the insulation fault location test current, and then determine the circuit where the ground fault occurs through the measuring transformer and insulation fault evaluator (ATK-IFLS120) installed on each load circuit in the system. The choice of injection frequency directly affects the effectiveness of the superimposed low-frequency voltage method in locating system insulation faults. When the frequency of the test power supply is changed and the frequency increases, the low-frequency current in the measurement loop continues to increase, mainly due to the influence of capacitive current. Because I=ωCU increases with the frequency, the capacitive current increases accordingly. The greater the injection frequency, the leakage current of the faulty branch and the non-faulty branch will be similar, making it difficult to realize fault line selection.
MULTI-CIRCUIT FAULT MONITORING AND ANALYSIS
Column cabinets and intelligent power distribution cabinets can be equipped with multi-circuit measurement devices to provide electrical measurement, alarm and recording information. The number of accessible loops, measurement items and communication functions should be determined according to the selected model.
The data-centre monitoring solution is intended for applications that organize condition monitoring and alarm management around distribution circuits. Select equipment and determine circuit quantities from the project single-line diagram.
RESIDUAL CURRENT MONITORING
The data center should select a monitoring solution based on the grounding method, power supply voltage, load characteristics and project protection requirements. Ungrounded systems can be configured with insulation monitoring and fault location, and grounded systems can be configured with corresponding types of residual current monitoring. Alarm thresholds, test signals, response times and subsequent protection actions should be determined according to the specific equipment and system design, and the values or functions of different solutions cannot be directly interchanged.
Related products:
§Insulation monitoring device
§Fault determination signal device
§Fault signal judgment device
§Multiple loop fault monitoring and analysis device
§Residual current monitoring device
