Continued from first part: Measurement of insulation resistance (IR) – Part 1 1. IR Values For Electrical Apparatus & Systems (PEARL Standard / NETA MTS-1997 Table 10.1) Max.Voltage Rating Of Equipment Megger Size Min.IR Value 250 Volts 500 Volts 25 MΩ 600 Volts 1,000 Volts 100 MΩ 5 KV 2,500 Volts 1,000 MΩ 8 KV 2,500 …
Measurement of insulation resistance (IR) – Part 1
Introduction The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. As a production test, this test is often used as a customer acceptance test, with minimum insulation resistance per unit length often specified by the customer. The results obtained from IR Test are not intended …
Single-Phase Power vs Three-Phase Power
The principal elements of an electric power system are the generating stations, the transmission lines, the substations, and the distribution networks. The generators produce the electricity, the transmission lines move it to regions where it is consumed, and the substations transform it for industrial, commercial, and residential use. Finally, the distribution networks carry the electricity …
Substation Main Functions and Classification
An electrical substation is an assemblage of electrical components including busbars, switchgear, power transformers, auxiliaries etc. These components are connected in a definite sequence such that a ckt. can be switched off during normal operation by manual command and also automatically during abnormal conditions such as short-ckt. Basically an electrical substation consists of number of …
How HV transmission lines affects humans and plants?
Introduction By increasing population of the world, towns are expanding, many buildings construct near high voltage overhead power transmission lines. The increase of power demand has increased the need for transmitting huge amount of power over long distances. Large transmission lines configurations with high voltage and current levels generate large values of electric and magnetic …
Using HVDC Technology For Transmitting Electricity
An alternate means of transmitting electricity is to use high-voltage direct current (HVDC) technology. As the name implies, HVDC uses direct current to transmit power. Direct current facilities are connected to HVAC systems by means of rectifiers, which convert alternating current to direct current, and inverters, which convert direct current to alternating current. Early applications …
Protection and Relays Used In Main Circuit Board at a Power Grid Substation
1. High speed biased differential relay The DMH type relay provides high speed biased differential protection for two or three winding transformers. The relay is immune to high inrush current and has a high degree of stability against through faults. It requires a max of two cycles operating time for current above twice relay rated …
Protection Of Generators And Transformers
As Generators and transformers are major components of a power system, so it is quite necessary to take all the preventive measures for the protection of transformers and generators. These are the following ways (ANSI codes) we use to protect transformers and generators from faults: 87/G1 Generator differential protection (87/G1): the protection is provided with …
Ceramic (Porcelain and Glass) Insulators
Materials Porcelain is the most frequently used material for insulators. Insulators are made of wet, processed porcelain. The fundamental materials used are a mixture of feldspar (35%), china clay (28%), flint (25%), ball clay (10%), and talc (2%). The ingredients are mixed with water. The resulting mixture has the consistency of putty or paste and …
EHV/HV Underground Cable Sheath Earthing (part 2/2)
Continued from previous part: EHV/HV Cable Sheath Earthing (part 1/2) Accessories for HT Cable Sheath Bonding 1. Function of Link Box? Link Box is electrically and mechanically one of the integral accessories of HV underground above ground cable bonding system, associated with HV XLPE power cable systems. Link boxes are used with cable joints and …
