Impact of power harmonics on precise and discriminative tripping of the relay system for earthing protection in underground 6 kV grids of Qung Ninh underground mines

2019 ◽  
pp. 28-34
Author(s):  
H.V. Bun ◽  
L.X. Thanh
Keyword(s):  
Underground Mines ◽  
Relay System ◽  
Power Harmonics

scholarly journals Identifying the efficiency decrease factor of motors working under power harmornic in 660V electric mining grids

2021 ◽  
Vol 15 (4) ◽  
pp. 108-113
Author(s):  
Le Xuan Thanh ◽  
Ho Viet Bun
Keyword(s):  
High Power ◽  
Low Voltage ◽  
Underground Mining ◽  
Harmonic Distortion ◽  
Underground Mines ◽  
Pumping System ◽  
Motor Efficiency ◽  
Load Carrying ◽  
Power Harmonics ◽  
Practical Implications

Purpose. Identify the motors efficiency decrease factor corresponding to various values of load-carrying ratio. Methods. Basing on the onsite measurements of power harmonic in 660V low voltage (LV) grids in Vietnam underground mines, simulations have been done on MATLAB and compared with mathematical models. Verifying data will be implemented in Lab-measurements carried out on pumping system to reveal series of decreasing factors. Findings. Series factors present the relation of the level of power total harmonic distortion (THD) and the decrease in motor efficiency with alternative load-carrying ratio. The factors will help mine operators to have better understanding of the power harmonics impact on 660V motors. Originality. The proposed factors and simulation in MATLAB may be applied to all underground mining grids with diffe-rent input parameters of THD. Practical implications. The research is implemented to identify the factors obtained from the operation of motors which work in high power harmonic environment. The resulting factors could be utilized to recalculate mining efficiency.

scholarly journals Research for Forming up the Controlling Diagram Utilizing the Connection of a LV Resistor on Voltage Transformer’s Open-Triagle Coil to Reduce over Voltage Caused by Earth Fault in 6 kV Grid of QuangNinh Underground Mines

2018 ◽  
Vol 35 ◽  
pp. 05001
Author(s):  
Ho Viet Bun ◽  
Le Xuan Thanh
Keyword(s):  
Single Phase ◽  
Underground Mines ◽  
Human Being ◽  
Relay System ◽  
Technical Parameters ◽  
Earth Fault ◽  
Electric Equipment ◽  
Open Triangle ◽  
Simulation Results

Single phase earth-fault in MV grids usually causes overvoltage that harm to human being and electric equipment. If the magnitude of over voltage is so great, many grids’ eco-technical parameters will be affected. The paper analyzes all possible consequences of over voltage occurred in 6 kV grid of QuangNinh underground mines. Base on the analysis, a controlling diagram utilizing the connection of a LV resistor on voltage transformer’s open-triangle coil to reduce over voltage is recommended. The simulation results of the diagram are used to prove the effectiveness of solution: the over voltage magnitude is only in the range of (2,1–2,4).Uf. Other advantage that solution brings to relay system will be pointed out.

Noise and vibration: Mine workers’ exposure in Quebec underground mines

CIM Journal ◽  
2015 ◽  
Vol 6 (2) ◽  
pp. 111-117
Author(s):  
Marcel Laflamme ◽  
Pierre Marcotte ◽  
Jérôme Boutin ◽  
Sylvain Ouellette ◽  
Gilles LeBlanc
Keyword(s):  
Underground Mines ◽  
Noise And Vibration ◽  
Mine Workers

Throughput and Energy Efficiency Maximization for Cognitive Relay System

2012 ◽  
Vol E95.B (1) ◽  
pp. 226-233 ◽  
Author(s):  
You XU ◽  
Yunzhou LI ◽  
Ming ZHAO ◽  
Hongxing ZOU
Keyword(s):  
Energy Efficiency ◽  
Relay System
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