Protection System Design of Overload, Short Circuit and Three-Phase Imbalance for Electromagnetic Starter in Coal Mine

2014 ◽  
Vol 1049-1050 ◽  
pp. 726-731
Author(s):  
Qing Hua Mao ◽  
Hong Wei Ma ◽  
Wang Xing ◽  
Yu Liu ◽  
Min Zeng

An intelligent protection system of electromagnetic starter in coal mine was designed. Its controller core is PLC LM3108K. The voltage rank of protection system is 660V and the electric current rank is 400A. It has protection functions for overload, short circuit, break phase and three-phase imbalance. The system achieved overload protection by using the method of inversing time overload. Greater the overcurrent is, Shorter the time of protective action is. The system achieved short circuit protection by using phase sensitive protection method, which improves sensitivity and reliability of short circuit protection. The system can display work status parameters and fault types timely by text LCD. It has the advantages of hardware circuit structure flexibility and automatically reset after fault relieved.

2011 ◽  
Vol 143-144 ◽  
pp. 14-18
Author(s):  
Dan Xu ◽  
Zhan Zhang

In view of the present our country coal mine high-voltage power grid widely used 6kV or 10kV cable direct power supply condition. To describe a DSP-based adaptive line selection leakage protection program of high-voltage power grid. It adopts under-compensation, adaptive random tuning and phase-sensitive comparison to judge the fault branch and achieve selective leakage protection, and make the protection system more perfect and reliable.


Author(s):  
Deni Almanda ◽  
Juniyanto Juniyanto

Pada saat terjadi gangguan hubung singkat di saluran transmisi Gardu Induk Plumpang, rele jarak berfungsi sebagai proteksi utama. Penelitian ini bertujuan untuk mengetahui pengaruh kompensasi impedansi urutan nol (kzn) terhadap kehandalan sistem proteksi rele jarak (distance relay) pada penghantar harapan indah di Gardu Induk Plumpang. Setting rele jarak yang didapatkan dari PT PLN (Persero) UPT Pulogadung disimulasikan menggunakan alat uji Omicron. Hasil simulasi gangguan hubung singkat satu fasa, gangguan hubung singkat dua fasa, dan gangguan hubung singkat tiga fasa menggunakan setting lama Z1 = 2.58 Ω, Z2 = 3.87 Ω, dan Z3 = 7.30 Ω, kZn = 0.93 Ω < -0.4° rele jarak tidak bekerja selektif, maka dilakukan resetting. Hasil resetting rele jarak yaitu Z1 = 2.58 Ω, Z2 = 3.87 Ω, dan Z3 = 7.30 Ω, kZn = 0.68 Ω < -0.6°. Setelah dilakukan resetting dan disimulasikan gangguan hubung singkat satu fasa, gangguan hubung singkat dua fasa, dan gangguan hubung singkat tiga fasa, rele jarak bekerja secara handal. Kesimpulannya kZn dapat mempengaruhi kehandalan sistem proteksi rele jarak pada penghantar harapan indah di Gardu Induk Plumpang.In the event of a short circuit in the transmission line of the Plumpang Substation, the distance relay serves as the main protection. This study aims to determine the effect of zero sequence impedance compensation (kzn) on the reliability of the distance relay protection system at the Harapan Indah conductor at the Plumpang Substation. The distance relay setting obtained from PT PLN (Persero) UPT Pulogadung was simulated using the Omicron test tool. Simulation results of single phase short circuit, two phase short circuit, and three phase short circuit using the old setting Z1 = 2.58 Ω, Z2 = 3.87 Ω, and Z3 = 7.30 Ω, kZn = 0.93 < -0.4° relay distance does not works selectively, then resetting is done. The results of resetting the distance relay are Z1 = 2.58 Ω, Z2 = 3.87 Ω, and Z3 = 7.30 Ω, kZn = 0.68 < -0.6°. After resetting and simulating single-phase short circuit, two phase short circuit, and three phase short circuit fault, the distance relay works reliably. In conclusion, kZn can affect the reliability of the distance relay protection system on the beautiful hope conductor at the Plumpang Substation.


2011 ◽  
Vol 317-319 ◽  
pp. 1259-1262
Author(s):  
Chun Yu Xu ◽  
Li Jun Zheng ◽  
Jian Cheng Song ◽  
Yun Guang Gao

The malfunction of short-circuit protection became increasingly serious in the fully mechanized face casused by large power equipment, more kind of loads and long distance power. According to the field requirements, the electrical characteristics between motor starting and three-phase short-circuit are compared, the phase-sensitive protection circuit combining current signal amplitude with power factor is designed, the protection data is tested and the protection characteristic is analyzed. The phase-sensitive protection circuit has been uesd in KJZ-4000-10(6)/3.3 flameproof and intrinsically safe load control center. The circuit is stable, sensitive and reliable. It has been proved that the short-circuit protection of power in underground is reliably realized.


2013 ◽  
Vol 329 ◽  
pp. 304-307
Author(s):  
Xu Dan

In view of the present our country underground lighting power grid comprehensive protection device existing problems, this paper introduces a DSP-based long distance lighting comprehensive protection device. Short-circuit protection using adaptive random setting mode. Leakage protection using additional DC measurement theory.The device has the function of cable insulation level, the network current is monitored real-time and grid parameters are displayed in turn, which make the protection system more perfect and reliable.


Author(s):  
Karan S Belsare ◽  
Gajanan D Patil

A low cost and reliable protection scheme has been designed for a three phase induction motor against unbalance voltages, under voltage, over voltage, short circuit and overheating protection. Taking the cost factor into consideration the design has been proposed using microcontroller Atmega32, MOSFETs, relays, small CTs and PTs. However the sensitivity of the protection scheme has been not compromised. The design has been tested online in the laboratory for small motors and the same can be implemented for larger motors by replacing the i-v converters and relays of suitable ratings.


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