Implementation of protection system used in high power transformer rating protection

CHAPTER ONE INTRODUCTION

The purpose of an electrical power system is to generate and supply electrical energy to consumers. The system should be designed and managed to deliver this energy to the utilization points with both reliability and economy. Many items of equipment are very expensive, and so the complete power system represents a very large capital investment. To ensure the maximum return on the large investment in the equipment, which goes to make up the power system and to keep the users satisfied with reliable service, the whole system must be kept in operation continuously without major breakdowns and also to reduce the impact of fault on the other parts of the system.

 Protection Importance

 

The importance of the protection lies in two basic points :

1- Detect faults and identifies how serious they are and where are their places. 2- Isolate the affected elements faults and opening the appropriate cutouts.

Protection System a complete arrangement of protection equipment and other devices required to achieve a specified function based on a protection principal.

Protection Scheme: a collection of protection equipment providing a defined function and including all equipment required to make the scheme work (i.e. relays, CT’s, CB’s, batteries, etc ).

Relays are the devices, which monitor the conditions of a circuit and give instructions to open a circuit under unhealthy conditions .

The basic parameters of the three-phase electrical system are voltage, current, frequency and power. All these have pre-determined values and/or sequence under healthy conditions. Any shift from this normal behavior could be the result of a fault condition either at the source end or at the load end .

Transformers are a critical and expensive component of the power system. Due to the long lead time for repair of and replacement of transformers, a major goal of transformer protection is limiting the damage to a faulted transformer. Some protection functions, such as over excitation protection and temperature-based protection may aid this goal by identifying operating conditions that may cause transformer failure. The comprehensive  transformer protection provided by multiple function protective relays is appropriate for critical transformers of all applications.

 Protection relays

 

A protective relay is the device, which gives instruction to disconnect a faulty part of the system. This action ensures that the remaining system is still fed with power, and protects the system from further damage due to the fault. Hence, use of protective apparatus is very necessary in the electrical systems, which are expected to generate, transmit and distribute power with least interruptions and restoration time. It can be well recognized that use of protective equipment are very vital to minimize the effects of faults, which otherwise can kill the whole system. Relays may be classified according to the technology used :

• Electromechanical relay: They work on the principle of a mechanical force causing operation of a relay contact in response to a stimulus. The mechanical force is generated through current flow in one or more windings on a magnetic core or cores, hence the term electromechanical relay and this relay can be classified into several different types as follows: attracted armature, moving coil, induction, thermal, motor operated, mechanical .

• Static relay: This term implies that the relay has no moving parts, Their design is based on the use of analogue electronic devices instead of coils and magnets to create the relay characteristic. Early versions used discrete devices but advances in electronics enabled the use of linear and digital integrated circuits
• Digital relay: In this type Microprocessors and microcontrollers replaced analogue circuits used in static relays to implement relay functions .

   Statement of problems

 

Faults occur in substation will eliminate the services from the units for this reason effective protection action is required to minimize damage and repair costs where it senses fault, Ensure safety of personnel.

 Objective 

The main objectives of this research are to develop and investigate protection system used in high power transformer rating protection.

 Methodology

The first stage in this project; numeric relays from ABB techniques used to obtain protection transformer. This protection using ABB REF615 which protect over current, restricted earth fault and differential protection.

On second stage selected setting of numerical According to IEEE Standers and ABB Technical guides.

On final stage run simulation to test the setting.

 

 Project layout

 

The thesis is organized as follow :

 

Chapter one gives brief introduction about relay in protection in electrical network and summarized research objectives and problem.

Chapter  two  contains introduction about    electrical section. Also contains detailed understanding to protect the transformer.

Chapter three contains the of numeric relay Hardware ,Relay interfaces and algorithms.

Chapter four testing of numerical relay with simulation before and after connection to transformer.

Chapter five conclusion and recommendations.

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AN ANALYSIS OF THE CAUSES, PREVENTION AND TREATMENT OF DAMPNESS  IN BUILDINGS (A CASE STUDY OF MAKOKO, LAGOS STATE)

INTRODUCTION

Dampness can be defined as water penetration through the walls and certain elements of a building (Halim et al., 2012). Dampness can also be defined as an excessive quantity of moisture contained in building materials and components which causes adverse movements or deterioration and results in unacceptable internal environmental conditions (Briffet, 1994).

Burkinshaw and Parrett (2004) defined dampness as the amount of moisture content present in a material and can be classified as capillary moisture content, equilibrium moisture content, hygroscopic moisture content, total moisture content and potential moisture content. Dampness is the most frequent and main problem in buildings and contributes more than 50% of all known building failures (Halim et al., 2012; Trotman, 2004).

According to Hollis (2000), dampness is inextricably linked to most building deterioration. A source of water close to a building will also be one of the problems associated with dampness. These problems include symptoms such as dirty spots on the building, biological plants like the growth of fungi, mosses and creeping plants, paint flaking, blistering etc. (Halim et al., 2012). In order to successfully diagnose and make appropriate recommendations for remedial actions, one should understand dampness and its impact on buildings.

The ultimate objective of any dampness study is to identify the lead source of moisture in order to recommend actions to remedy the problem (Halim et al., 2012). According to Hollis (2000), sources of dampness can be classified as rising dampness, penetrating dampness, condensation and pipe leakages. According to Burkinshaw and Parrett (2004), dampness can be classified as air moisture condensation, penetrating dampness, internal plumbing leaks, below ground moisture or building specific sources.

Rising dampness occurs as a result of capillary suction of moisture from the ground into porous masonry building materials such as stone, brick, blocks, earth and mortar (Halim & Halim, 2010; Ahmed & Rahman, 2010; Riley & Cotgrave, 2005; Trotman et al., 2004; New South Wales Heritage Office, NSWHO, 2005). The moisture evaporates from either face of the wall (inside or outside), allowing more to be drawn from below. The height to which the moisture will rise is determined by the evaporation rate and the nature of the wall (Halim & Halim, 2010; Ahmed & Rahman, 2010; Trotman et al., 2004; Riley & Cotgrave, 2005; NSWHO, 2005). The normal limit for rising dampness ranges from 0.5 m to 1.5 m above ground level (Halim & Halim, 2010; Ahmed & Rahman, 2010; Trotman et al., 2004; Riley & Cotgrave, 2005; NSWHO, 2005). Rising dampness may show as a high-tide-like stain on wall paper and other interior finishes, and, when it is severe, as blistering of paint and loss of plaster. Damp walls encourage the growth of mold which in conjunction with high humidity, can lead to health problems to occupants (Halim & Halim, 2010; Ahmed & Rahman, 2010; Trotman et al., 2004; Riley & Cotgrave, 2005; NSWHO, 2005).

Water penetration through a building enclosure depends on the simultaneous occurrence of three things: the presence of water; an opening through which water can enter and a physical force to move the water (Beall, 2000). Water can be present as rain, melting snow and soil moisture. Several forces such as gravity, air currents, capillary suction, surface tension, kinetic energy, air pressure and hydrostatic pressure influence the penetration of water into buildings (Beall, 2000). Drips from air conditioning or hot water system overflows, rain water, pipe leakages, water from horizontal directions, etc. can also cause penetration dampness in buildings (NSWHO, 2005). These sources tend to produce small, localized patches of dampness and decay, whereas rising dampness may affect the base of a whole building (NSWHO, 2005).

According to Curtis (2007), dampness resulting from condensation occurs where water in the air inside a building condenses on a cooler surface. This is usually indicative of cold spots in the building, sometimes called cold bridges (Curtis, 2007). It can also occur where there is poor ventilation or where short intense heating cycles do not allow the walls to fully warm up (Curtis, 2007). This situation allows the heated air to hold more water, which condenses when the temperature drops (Curtis, 2007). Excessive condensation frequently results in severe mould growth which can in turn create health hazards. Condensation is one of the most common forms of dampness in residential buildings, mainly caused by warm moist air formed from cooking, washing, bathing or even by just breathing, condensing onto colder surfaces in the homes (Burns, 2010). Damp patches can appear on plaster walls in odd places, particularly on outside walls, often appearing and disappearing on a regular basis (Burns, 2010). Condensation is mostly accompanied by mold which is black in colour but can virtually be of any colour and is very common on walls and ceiling, underneath bay windows, etc. (Burns, 2010). According to the British Research Establishment (BRE), 80-85% of dampness problems in the United Kingdom arise due to condensation or manmade moisture (Ryan, 2002).

There are many visual signs to look out for when diagnosing any damp situation (South Northamptonshire Council, SNC, 2012). In Denmark, rising dampness in the walls of buildings is associated with symptoms such as salt efflorescence, deterioration of rendering and plastering mortar, deterioration of wooden parts of buildings, etc. Condensation is associated with mold growth, usually on top of walls and ceilings (Burns, 2010). Rising dampness may show as a high-tide-like stain on wall paper and other interior finishes, and, when it is severe, as blistering of paint and loss of plaster (Halim & Halim, 2010; Ahmed & Rahman, 2010; Burns, 2010; Curtis, 2007; Trotman et al., 2004; Riley & Cotgrave, 2005; NSWHO, 2005). Mold growth may also be associated with rising and penetration dampness in buildings (Burns, 2010). The 1991 House Condition Survey found that 10.4million homes were affected by mold growth (Ryan, 2002; Wheeler & Critchley, 1998) and the Northern Ireland House Condition Survey in 1996 also found that 16% of homes experienced some form of mold growth (Ryan, 2002).

 

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General Introduction

 

The construction industry in Saudi Arabia is the largest and fastest-growing market in the Gulf region (Samargandi et al., 2013). Its organisational culture, labour and material supply chain, business strategies, and management skills are different from other parts of the globe. For example, the Kingdom of Saudi Arabia (KSA) has a strong economic standing, which leads its government to take the opportunity to spend money on many public-funded infrastructure projects. The KSA has experienced a construction boom with over 5,200 ongoing public infrastructure projects having a total value equal to US$819 billion (Argaam, 2021). However, Saudi Arabia failed to make real progress in achieving good management and organisational performance as most projects are experiencing delays and cost overruns (Abdellatif and Alshibani, 2019; Mahamid, 2013; Mosley and Bubshait, 2016). A proper QMS development and its practice throughout the project’s life-cycle and its associated organisations are essential to overcome these poor project delivery performances.

 

Accordingly, Al-Otaibi et al. (2015) discovered that Saudi Arabian construction firms’ performances could be promoted over their counter companies by effectively practising the Total Quality Management (TQM) system. In particular, the TQM has a strong positive correlation improving construction quality culture, which is a critical issue to the project owners. Mazher et al. (2015) studied the effectiveness of TQM in the Saudi construction industry considering four dimensions, such as quality control, management, assurance, and inspection. They applied regression analysis and found quality management and assurance have strong positive significance to the project quality assurance. Aichouni et al. (2014) conducted an empirical study on the adaptation challenges of some already developed quality management systems in the Saudi construction industry. They discovered that organisational culture is the main barrier to implement those tools and techniques in this region. In a further study in Saudi Arabia, Abazid and Gökçekuş (2019) discovered that organisational culture, higher authorities’ willingness to adapt and customize the TQM system, reliability and tangibility dimensions are the main problems in implementing a quality management system. Previous research in other countries also identified that specific company culture, business performance, strategy to quality control, country’s development policy, etc., are distinct and directly linked to the QMS of a company or organization (Bhatia and Awasthi, 2018; Fundin et al., 2018). Thus, a country or company-specific QMS development and practice is a critical need. However, no study in the KSA proposed any QMS model, which can readily be adopted or accommodated local construction issues and culture in construction quality management.

As construction projects usually involve large quantities of resources and many dynamic processes, achieving high quality is end-product-based and depends on managing interrelated organisational processes (Masuin et al., 2020). Among many factors, information system management, quality of reporting documents, recording of quality-related data like inspection, identified issues, and collaboration among the stakeholders to resolve the issues ensuring

intended quality control are significant to develop and practice standard QMS for an organization (Lee et al., 2020; Ma et al., 2018). The mere existence of information management and quality documentation does not necessarily reflect the presence of deep-rooted operational practices and procedures needed for ensuring the ultimate delivery of a well-operated Quality Management System (QMS). Some human factors such as level of learning, building dynamic capability, knowledge integration with a flexible strategy to a product or service are also significant to practice QMS throughout the production supply chain (Gutierrez-Gutierrez et al., 2018). These particular issues, i.e., the company’s culture and strategies to quality assurance, information documentation and management, and human factors in QMS, did not discover any previous study in the KSA. Thus, this paper aims to develop the Quality Management System (QMS) for construction companies in the KSA. In recent years, many researchers have focused on developing and adopting company-based QMS systems using the SERVIQUAL model, TQM, and International Organization for Standardization (ISO) tools (Bhatia and Awasthi, 2018). Towards developing QMS for the KSA construction industry, this study conducted a structured focus group interview with the experts of specific construction companies, followed by two case studies to develop company-specific QMS and its implementation guidelines based on ISO tools

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