How to Improve Voltage Regulation in Power System?

Voltage Regulation Improvement in Transmission Lines

If we consider how the high voltage in the transmission lines should be regulated, then the answer is with a transformer.

But if we consider how the voltage is increased in an already operating transmission line, this can be done by couplers in the transformer or by decreasing the number of turns in the transformer, thereby raising or lowering the voltage.

Why Need Power Cable Test After Installation

Power Cable Test After Installation

HV/EHV power cable testing in the field after installation is a common requirement for cable users. Meanwhile, MV-normal voltage, HV-high voltage, and EHV-extra high voltage power cables are carefully tested by the manufacturer before consignment with AC-alternating or DC-direct voltage. 

Why are Some Colored Balls Mounted on High-Voltage Power Lines?

Aerial Marker Balls and Balisor Attached to High Voltage Power Transmission Lines

If you come across a high-tension overhead power transmission line conductor, some colored balls hanging on those conductors will catch your eye. Seeing them, you must also have a question: what is their usefulness? Are they applied just for decoration?

Feeder Booster for Electrical Transmission Lines and Its Functions

What is Feeder Booster for Electrical Transmission Lines?

A feeder booster is an important piece of equipment for electrical energy transmission lines, especially for long feeders of transmission lines where the voltage drops at the endpoint due to some technical limitations of transmission lines that are not easy to eliminate as required.

Voltage Transformer-VT using

Fig-Voltage Transformer-VT

What is a Voltage Transformer (VT)?

VT is the abbreviation Voltage Transformer; on the other way PT or Potential Transformer is a transformer that converts the voltage into a standard measurable level. 

This converted voltage is then proportionally transformed into the measuring or controlling primary voltage. 

Challenges for Underground Distribution in Dhaka City

 

Underground Power System Distribution in Dhaka City is a Big Challenge 

Dhaka faces high capital costs, extreme population density, very limited street footprint, waterlogging, scarce equipment space, existing utility conflicts, and poor inter-utility coordination — each of which raises technical, financial, and institutional barriers to rolling out a modern underground distribution network.

Conductor Stranding Perspective of Power Cable Construction

Conductor Stranding Perspective of Power Cable Construction

Conductor stranding is a major aspect of cable construction that came long experience in different circumstances. 

The problem with larger sizes of solid conductors is too rigid for installation in curvy areas, jointing, and termination work. The solution to these difficulties comes from conductor stranding. 

The procedure of stranding is used depending on the metal temper and types. In general Copper conductor and Aluminum, copper conductors and aluminum conductors are used for power cable construction. Normally Aluminum is softer than Copper, so the use limit is higher than that of copper.

Fig: Conductor strands arrangement system

Electrical Power Cable Is an Electrical Transformer

An Electrical Power Cable Is an Electrical Transformer

How does an electrical power cable work as an electrical power transformer? It may be your question. It’s true that we know electrical power cable works as a capacitor, because the condition to be a capacitor, two metallic components need to be placed in parallel. 

What Is The National Electric Grid of a Country?

What Is the Meaning of National Grid?

Grid means the high voltage backbone system of interconnected transmission lines, substations, and generating plants. Also known as the Transmission System. 

An electrical grid of a country is the interconnected whole electrical network for delivering electricity from generating units to consumers' use points. 

The National Grid consists of generating stations that produce electrical power, the high voltage transmission lines that carry electrical power to distant consumers' end from generating sources, where many sources and transmission lines are interconnected in a common network system. 

Electrical Load Flow Analysis in Power Network System

Load flow (or power flow) in a power network system is an analysis that calculates how electrical power is distributed and flows through an electrical power system from the generation sources to the loads (or consumers). The main objectives are to determine the voltage levels at each bus (node), and the power flowing through each transmission line, and to ensure the system is operating within its limits and constraints.

What Happen If Cables Placed In Magnetic Metal Conduit

What Happens If Cables are Placed In Magnetic Metal Conduits 

Do we know what happens if cables are in a magnetic metal conduit? Yes, at least we know that in any circumstances, the individual phase of an AC (alternating current) circuit is in a separate magnetic metal conduit. 

MYSTERIOUS CORONA EFFECTS IN TRANSMISSION LINES

Fig-Corona Effect in Transmission Line Visible at Night

What Are Corona's effects on electrical energy transmission lines?

If you look along the high voltage power transmission line in a clear sky at night, you will observe the dreamiest violet glow phenomenon embedded with hissing noise along the transmission line conductors. This indefinable phenomenon causes nothing but a production of ozone gas surrounding overhead electrical energy transmission lines known as the Corona or Corona effect.

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  

Sponsored:

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. 

Bangladesh Power Transmission and Distribution Line Privatization Plan

Bangladesh Power Transmission and Distribution System Planned to Operate through Private Ownership.

National electricity transmission and distribution line going to the private sector As a result, the private sector is also involved with the transmission system after the production of electricity. In the meantime, plans have been made to construct two transmission lines through the private sector.

Besides, the government has set a target of investing more than 4.5 billion taka by 2040 in private power sector. In this case, new investors will be given preference.

How Vibration Damper Works in Transmission Line?

How Does a Small Size Damper Reduce Vibration in Transmission Lines?

Vibration dampers are usually used in high voltage and extra-high voltage electrical energy overhead transmission lines to handle aeolian and galloping or dancing vibrations in the transmission lines' conductors. The dampers are designed in such a way that they attenuate the line vibrations by reaching the same frequency as the cable that has wind-induced vibrations.

The overhead Transmission Line mainly experiences two types of vibrations in a vertical plane which can be categorized into two groups.

• Aeolian Vibration;
• Galloping or Dancing vibration.

What Is the Voltage Classification?

Nominal Voltage Classification in Transmission and Distribution System

To identify the voltage level effortlessly in a transmission and distribution system a significant voltage classification is essential. The voltage class is used not only to identify the level of system voltage, but the main importance is to classify the Apparatus voltage ranges for the operation and maintenance of an electrical energy transmission and distribution system.

Hissing Sound from High Voltage Power Transmission Line: Troubleshooting

Troubleshooting the hissing sound from cable termination just after energization of the high voltage transmission line.

Hissing sound troubleshooting for high voltage underground XLPE cable electrical power transmission line after successful commissioning test. The badly hissing sound coming from the cable termination port area into the panel. Due to the newly constructed line just energizing, so switch off immediately hearing the hissing sound. 

Wireless Electrical Energy Transmission

WEET, wireless electrical energy transmission is now an issue to transfer electrical power on large-scale and longer distances; because wireless energy transfer system is not a new question. Electrical energy transmission networking systems already use wireless energy transfer technology or unlike direct electrical connection. WEET system will be clear if you review your knowledge about the basic working principle of electrical transformers.

Now today’s target is to transfer electricity without wire from the source to the consumer’s end on a large scale. Already there are many demonstrations and operational stuff regarding wireless electricity transfer on a normal scale, like- mobile battery chargers, operating TV, laptops, etc. devices.

What Is the Wireless Electrical Energy Transmission Technology?

Engineers’ are searching for a practical technology to transmit electrical energy

Why Happen Over-voltage In Power System?

The Major Causes to Why Over-voltage Develop in  Power Distribution System.

The causes of happening over-voltage in the power transmission system may many more reasons. In short, we can define internal causes and external causes to develop over-voltage in electrical power transmission or distribution networks. We can sum up the whole causes of overvoltage in the power system in the major five cause as below:

1.     Power System Surges:

If absence or poor quality devices like Relay, AVR, Auto-transformer Auto-transformer regulator etc. are used in the transmission network, the system will function as poor regulation of the power source that may cause voltage fluctuations either over or under. This type of power supply system may cause serious damage to users’ equipment, especially to electronic or computer-controlled equipment;

2.     Insulation Failure:

This is the most common reason failure the insulation of conductor and cause grounding or near to grounding of the conductor. Failure takes place when there is no insulation between the line and the earth that allows the current to flow downward or earth;

3.     Arcing Ground:

This happens normally in the three-phase system when there is the presence of a sporadic arc in line-to-ground fault. In this case, short-live oscillations are produced, if this happen continuously or again and again that would be a serious problem for system cause of insulation breakdown of the connected equipment;

4.      Resonance: 

Happening resonance is a bad effect on the power system. In this case when resonance occurs means when the value of the inductive resistance becomes equal the value of capacitive resistance, system voltage increases absurdly;

5.      External Causes:

Above mentioned causes are mainly happening internally in the system. Many causes may happen externally to the system and may inject over-voltage into the system. Lightning is one good example that is responsible for the high magnitude of surges, leading to very serious high voltage injection to the system.

What Is Internal Causes for Over-voltages?

Demonstration of Over-voltage developing in the steady system:

Sponsored:

There are many internal causes for over-voltage in the power distribution network, we will focus only on some main causes for over-voltage that will help to over-voltage detection and selection of over-voltage protection devices like an over-voltage relay, over-voltage AVS, over-voltage detection circuit specification, etc. and finally help to protect the system from over-voltage damages or over-current damages.

The definition of over-voltage may define as “the excess potential required for the discharge of an ion at an electrode over and above the equilibrium potential of the electrode”; in short- voltage over the normal operating voltage of a device or the system is known as over-voltage.

The major internal causes for developing over-voltage is as-

a.      Switching Operations on Unloaded Line;

b.      Sudden Opening of Loaded Line;

c.      Insulation Failure;

d.      Arcing Grounds;

e.      Resonance, etc.

Internal over-voltages actually two major groups first- for switching over voltages or Transient over operation voltages of high frequency and second temporary over-voltages.

Switching over-voltages are caused when switching operation is carried over the network system, Ferranti Effect the receiving end voltage is increased when an unloaded long line is charged or stitch ON, similarly, overvoltage of transient nature occurs when the primary side of the transformers or reactors is switched ON.

Temporary over-voltages may occur due to disconnect a major load from the long line under normal or steady-state condition.

What Are External Causes for Over-voltages?

The external causes of over-voltage may occur due to various reasons from atmospheric disturbances, it originates mainly due to lightning that takes the form of a surge and has no direct relationship with the operating voltage of the system network. The major cause of external over-voltage developing in the system is as-

a.      Direct lightning stroke;

b.      Indirect lightning strokes;

c.      Electromagnetically induced over voltages due to lightning discharge taking place near the line, called 'side stroke';

d.      Voltages induced due to atmospheric changes along the length of the line;

e.      Electrostatically induced voltages due to the presence of charged clouds nearby; &

f.       Electrostatically induced over voltages due to the frictional effects of small particles like dust or dry snow in the atmosphere or due to change in the altitude of the line.

What Happen Due to Over-voltage in Power Distribution Network?

Sponsored:

All line equipment and appliances desire a stable power supply to function properly in its long span of life. Overvoltage is disposed to stress the insulation of the electrical equipment’s and possible to cause damage to them when it frequently over-voltage hits them. Especially for electronic circuits, over-voltage is very harmful to them.

Inline equipment, over-voltage may cause in spark over and flashover between phase and ground at the weakest point in the distribution network and the result is damages property if not the over-voltage protection devises function.

If you have more information about over-voltage, over-voltage protection and over-voltage devices share in comments.

SURGE ARRESTERS SPECIFICATION FOR 132 KV & 33 KV LINE

Surge Arrester Specification

Surge Arrester Requirements for 132kV and 33kV Underground Cable Line Projects

 

Surge arresters shall be of the type employing non-linear metal oxide resistors without spark gaps. The Contractor shall demonstrate by calculations that the surge arresters will adequately protect the switchgear arrangement proposed.

Arresters shall be designed and tested in accordance with the requirements of IEC 99 4. Any departure shall be the subject of agreement between the Engineer and the Contractor. Routine tests shall be carried out in accordance with the requirements of Section 15 of this Specification.

Surge arresters shall be housed in porcelain insulators designed to withstand extremes of the environment described. The insulation shall have a minimum creepage distance of 25 mm/kV rated system phase-to-phase voltage. Porcelain shall comply with IEC 233. The method of sealing against the ingress of moisture shall be of a type well proven in service and the manufacturing procedures shall include a practical leak test which can be demonstrated to the inspecting engineer if required.

The internal components of arresters shall be arranged to minimize radial voltage stresses, and internal corona and to ensure minimal capacitive coupling with any conducting layer of pollutant on the outside of the porcelain housing except where approved, organic materials are not permitted.

Good electrical contact shall be maintained between resistor blocks, considering any thermal expansion and contraction of the block or mechanical shock during transport and erection, by installing a well-proven clamping system.

Metal oxide arresters installed outdoors shall be able to dissipate when new, twice the energy generated in the resistor blocks when energized at their maximum continuous operating voltage immediately having been subjected to the discharge duties specified in IEC 99 4 and assuming that the porcelain housing and the surrounding air is at least 5˚C higher than the maximum ambient air temperature specified.

Good quality control of the manufacturing process of the resistors shall be ensured by rigorous testing procedures. The procedures shall ensure that the characteristics of the blocks are, and will remain, within the specified limits when new and throughout the anticipated life of the arresters. Samples may be selected at random by the Engineer for special tests to be agreed upon with the manufacturer.

All surge arresters shall be fitted with a pressure relief diaphragm which shall prevent explosive shattering of the porcelain housing in the event of an arrester failure and the arrester shall have been tested according to the high and low current tests specified in IEC 99 1.

Arresters shall be supplied completely for installation in an outdoor switchyard, including supporting structures, insulating bases, and surge counters, one per phase, and, if applicable, grading rings. The material used for terminals shall be compatible with that of the conductors to which they are to be connected.

Each arrester shall be identified by a rating plate in accordance with the requirements of IEC 99 4. In addition, an identification mark shall be permanently inscribed on each separately housed unit of a multi-unit arrester so that units can be replaced in the correct position in the event of them being dismantled.

Surge counters shall have an internal assembly that is matched to the line discharge capability of the arrester and shall include a leakage current meter with a bilinear scale for ease of reading. Auxiliary contacts are to be provided to signal remote indications of the counter operation.

Sponsored:

Technical Data Schedule for 132 kV and 33 Surge Arrester

Sl. No.	Item no.	Unit	Nominal System Voltage
			132 kV	33 kV
1.	Manufacturer
2.	Model Number
3.	Type:
4.	Continuous operating voltage	kV RMS
5.	Rated voltage	kV RMS
6.	Standard nominal discharge current	kV
7.	Reference current at ambient temperature	mA
8.	Reference voltage for above	kV RMS
9.	Steep current impulse residual voltage	kV pk
10.	Lightning impulse residual voltage at
	5 kA	kV pk
	10 kA	kV pk
	20 kA	kV pk
11.	Duty Class
12.	Discharge Class
13.	Pressure relief class
14.	Nominal Diameter of resistor blocks	mm
15.	Number of resistor blocks connected electrically in parallel
16.	Number of separately housed units pre-phase
17.	Overall height of arrester (without supporting structure)	m
18.	Overall height of arrester including grading ring if applicable	mm
19.	Clearances:
	Phase to earth (from center line)	mm
	Phase to phase (center line to center line)	mm
20.	Overall height of arrester (without supporting structure)	kg
21.	Maximum cantilever strength	Nm
22.	Maximum force due to the wind (at maximum specified gust speed)	Nm
23.	Minimum creepage distance over the insulator	mm