Electrical Substation Equipment: Instrument Transformer and Its Functions

Fig-Instrument Transformer CT&PT

An instrument transformer is a type of electrical device used in power systems to facilitate the measurement, protection, and control of electrical quantities. It transforms high voltage and high current levels commonly found in power systems into standardized values suitable for measurement and monitoring by instruments and relays. There are two main types of instrument transformers: current transformers (CTs) and voltage transformers (VTs), also known as potential transformers (PTs).

What is the Frequency Relay and How Does It Work?

A frequency relay is a protective device used in electrical systems to monitor the frequency of the power supply and initiate appropriate actions or alarms when the frequency deviates from the normal operating range. Its primary function is to detect abnormal frequency conditions and protect the power system from potential damage or instability.

Fig-Frequency Measurement Idea, credit Wikimedia

Frequency Relay and Its Working Principle

What Are the Key Benefits of Partnering with an MVP Development Company?

What are the Key Benefits of Partnering with an MVP Development Company?

 

The simplest definition of an MVP is that it enables you to validate your business idea with the least amount of time and money spent. The Minimum Viable Product has succeeded in a domain where numerous startups have competed for the same customers, and companies try to effectively meet profitable ideas.

Cable Pulling & Jointing Tools and Equipment

Cable pulling, Jointing, and Termination equipment play very important roles to ensure quality work to operate a safe and long-life operation. Cable pulling tools make for easy and safe cable laying, less cable sheath or screen damage/scarce, applying pulling tension correctly, and spacing cable in trench or duct properly. Cable Joint and Termination tools are very much special for cable jointing and cable sealing end termination.

How Use Cable Pulling Tools & Prepare Cable Trench?

Before laying cable, cable trench or cable duct must prepare as per site requirement. Cable ducts or trench measurements will not same for all, depending on the voltage rating, cable size, laying location, and other vicinity factors cable ducts or trenches' depth and width vary.

ARMOUR EARTHING ASSEMBLING FOR SINGLE CORE CABLE

Armour Earthing Assembly for Wire Armour Single Core Cable

33kV Cable Earthing System

Cable armour earthing is important for medium voltage (MV), high voltage (HV) and extra high voltage (EHV) system. 

Our discussion on this article is limited only single core plastic or paper cable wired armour earthing procedure for medium voltage (MV) system or 7.2 kV to 36 kV ranges.

The crystal clear step-by-step assembly figure shown the complete procedure of earthing system for wired armour cable.

If you follow the shown 9 step carefully, we hope you will be able to assemble the cable armour earthing successfully.

9 Step to Earth Cable Armour  

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1. First of all remove the over-sheath according to the dimension given the appropriate manufacturer Installation Instruction, Remove the armour according to dimension as per shown in the drawing. Clean the end of the over-sheath for a length of 250 mm.
2. Then slide the outer sleeve over the cable, and disassemble the clamping rings. Slide one clamping ring lug-downwards over the cable as shown in the figure 2.
3. Following the figure no-3 spread the armour wires as shown in the drawing and screw the other clamping ring loosely to the lugged clamping ring.
4. Install the termination in accordance with the Installation Instruction of termination manufacturer. Pass the end of the earth lead down through the clamping rings and connect it to one lug of the clamping ring. Tighten the clamping rings, refer to figure no-4.
5. With a small overlap and slight tension wrap two layers of sealant tape round the overs-heath for a length of 50 mm, just below the armour wire ends. Wrap two layers of sealant tape round the earth conductor so that it will be just below the armour wire ends. Attach the earth conductor to the other lug of the clamping ring as figure-5.
6. As shown in figure-6, bend the armour wires back and bind the ends to the over-sheath with a wire binder or plastic tape. noted that all sharp wire ends must be covered with plastic tape.
7. With a slight tension and small overlap wrap two layers of sealant tape over the lower end of the termination for a length of 50 mm.
8. Position the top end of the outer sleeve level with the top of the sealant tape. Shrink it into place starting at the center. Shrink the lower end first and work towards the upper end.
9. Yes, you have done; installation of earthing assembly for armour is completed.

This is the basic instruction for cable armour earthing, to do it physically you must follow the manufacturer installation instruction and necessary safety code. If it is helpful, then share with others to help them. 

Why Does Transformer Impedance Descrive in Percentage?

Fig-A Typical Transformer

Describe Why Does Transformer Impedance  Measured in Percentage

The rated impedance of a transformer is the voltage drop on full load because of the winding obstruction and spillage reactance communicated as a level of the evaluated voltage.