FAULT PREVENTION MANAGEMENT SYSTEM FOR THE UNDERGROUND DISTRIBUTION FACILITIES USING 3D GIS
A SEMINAR REPORT
Submitted
By
NIKHIL.P.S.
ELECTRICAL AND ELECTRONICS ENGINEERING
P.A .AZIZ COLLEGE OF ENGINEERING & TECHNOLOGY

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CHAPTER 1
INTRODUCTION

Underground distribution facilities are generally constructed at densely populated districts with a concentrated power load,mainly for improvement of appearance. Cities with electric cables, poles, or transformers laid underground have reduced traffic problems and are much more scenic. However, underground distribution facilities are restrictively constructed as they cost around 30 times more than the normal overhead distribution facilities. The first underground facilities in Korea, mainly in central Seoul, were constructed in the 1980s. The length that these underground distribution facilities cover has increased more than 4 times as long as that in 1991(from 5,179 c-km in 1991 to 23,608 c-km in 2006), proportional with the growth of the South Korean economy.To add perspective to this growth, commercial and business areas in central Seoul have hardly any underground space as it is full of facilities for electricity, communication, gas, water supply, sewer, etc. Therefore, when maintenance work on roads or water supply facilities is carried out, the power supply facilities are occasionally damaged, resulting in power failure.

The underground distribution facilities were recorded on blueprints, and the 2D GIS (Geographic information system) was introduced in 1998 for more effective recording and management of location, type, construction date, etc. of facilities. However, there has been difficulty in management as some 2D GIS data were not matched with the actual facilities on site. 35% of power failures are occurring from external damage every year as the 2D GIS does not provide accurate facilities information.KEPCO (Korea electric power corporation) has been constantly inspecting underground facilities to maintain superior condition, but it has not been easy as almost all the equipment has been buried underground. Even with regular inspection, 35% of facilities failures are caused by deterioration on the average each year as maintenance is not performed due to the lack of maintenance engineers. Therefore, it is necessary to reduce facilities failures caused by external damage and deterioration (70% of all failures). If underground facilities in densely populated areas are damaged, they can cause huge problems such as blackouts affecting shopping centers, hospitals, government offices, transport systems, financial offices, etc. It takes considerable time for power company’s engineers to examine and recover the failure, so that it is difficult to provide high quality electricity to customers.There was a case-study presentations on how electricitysystem management could be visualized on a ship. Also, Professor Yotaro Hatamura pointed out in his learning from failure (based on ’1:29:300 theory’ by Professor Heinrich) that the problem must be solved before they occur. This paper analyzes the present states and a problem of the current facilities management system based on manpower, apply the new Construction and Management System for the Underground facilities on site, and evaluates the result and outcome of the new system. Hereafter, the system can be linked with UIS(urban information system) for more efficient underground facilities construction, management and maintenance system.

CHAPTER 2

DEVELOPMENT OF CONSTRUCTION AND
MANAGEMENT SYSTEM FOR THE UNDERGROUND
FACILITIES

The management system for the underground facilities is divided into planning, construction and operation. Planning will not greatly affect the optimum management of the facilities if the building material, manpower, equipment and budget are appropriate. However, construction and operation need more thorough on-site control as they are directly related to the failure of facilities. Prevention of failure has limitations as the construction and maintenance of underground facilities are mainly conducted by manpower.

2.1 UNDERGROUND FACILITIES AND PRESENT STATE

In order to supply power through underground lines, the voltage(22.9kV-y) stepped down in the substation(154kV) is transmitted through cables to the primary terminal of a pad mounted transformer near a customer. The electricity is supplied to the customer through a low voltage cable connected to 200V or 380V secondary terminal. The main equipment used for underground distribution systems is pipelines, manholes, handholes, connection boxes, cables, pad mounted transformers, pad mounted switchegears, multiple circuit breakers, rising poles, etc. Depending on the development of economy, customers have increased from 14.1mil. in 1998 to 17.6 mil. in 2006, and the percentage of underground distribution facilities also sharply increased from 8.9% in 1998 to 12.3% in 2006.



2.2 UNDERGROUND DISTRIBUTION FACILITIES MANAGEMENT AND MAJOR FAULT TYPES

Underground distribution facilities faults have been decreasing during the past seven years due to the replacement of old equipment and the improvement in the quality of material and equipment used. Even though the number of faults has been decreasing, the ratio of facilities failure caused.


Table 2.1 Underground distribution facilities


Fig. 2.1 Causes of underground distribution facilities faults

Therefore, it is urgent to reduce the facilities failure caused by external damage and deterioration by analyzing the reasons for failure. Causes of external damage on underground distribution facilities are shown in Fig. 2.3 From 1998 to 2006, 80% of external damages were due to civil work, road construction, subway work, and water supply and sewer work carried out near underground distribution facilities. 4% of distribution facilities damaged were done even by electrical work. This clearly shows the facilities management and maintenance system based on manpower has limitations. In many cases, the work was carried with insufficient information about the location of underground facilities and the original condition of the construction work, which resulted in failures. Fig. 2.2 is the map and photo of underground facilities searched on the current 2D GIS. 2D GIS does not provide detailed information on depth of the facilities, condition of foundation, method of construction, material in use, etc.


Fig. 2.2 Map of underground facilities

It was analyzed that the inspection by the system was not available so that facilities which must be inspected were left off, resulting in failures from deterioration.

Fig. 2.3 Cause of external damage on underground distribution facilities


2.3 ANALYSIS ON THE UNDERGROUND DISTRIBUTION FACILITIES FAILURE AND RECOVERY PROCESS

As a result of analyzing the current failure and the recovery process due to external damages and deterioration of the underground distribution facilities management process, if a fault occurs, as shown in Fig. 2.4, field inspection is performed to collect information, and recovery measures are put into action. In this process, the movement to the fault spot is time-consuming but this movement is necessary to judge the required materials, equipment, and underground conditions, and also to prepare the actual recovery. This problem can be solved to some extent by utilizing the 3D GIS Tool to film the site digitally before the construction begins, store it in the DB and then use it. In this way, improvements can be achieved in the working process. When public works are performed near the underground distribution facilities or there are deteriorated equipment, it is still possible to prevent power facilities failure by referring to the pre recorded digital videos and verifying the exact location of the underground distribution facilities in the 3D GIS using GPS coordinates

Fig. 2.4 Map and photo of underground facilities diagram on 2D GIS.




Fig. 2.5 Construction management system


2.4 THE CONSTITUTION AND DEVELOPMENT OF THE UNDERGROUND DISTRIBUTION FACILITIES CONSTRUCTION MANAGEMENT SYSTEM

The pre-stored equipment attributes, location coordinates, power distribution facilities, and data in the NDIS (new distribution information system) and NGIS (national geographic information system) topographical maps of the underground distribution facilities construction management systems were used to make Autocad Maps and Arcinfo 2-dimensional Shape Files. The 3D GIS Tool named as XD Builder was then used to transform it into 3D, combining it with the topography, and the 3D facilities and attributes were stored in the DB. It was structured so that the user could create, inquire, and adjust facilities information, inspection and maintenance, and histories on the web. The system development consists of 5 stages. In the first stage, in order to build 3D facilities DB, information on the nlocation of pipelines, manholes, pad mounted switchgears, pad mounted transformers, cables, etc. and attribute information such as specification, volume, quantity, installation date, vendor, etc. were extracted from NDIS, and contours and roads of the topographical map from NGIS. Consequently, a shape file was made. In the second stage, in order to construct facilities, the pipelines were arranged in columns and rows, and a shape file was prepared to structuralize the roads by classifying the pipelines with Autocad Map and Arcinfo Tool.

In the third stage, in order to build 3D facilities DB, facilities edited by GIS 2D Tool were transformed to obtain values X, Y, and Z, and coupled with topographical contour shapes. The real locations were expressed in the topographical map, and texture mapping was used to make it similar to the real one. In the fourth stage, in order to build basic attribute data, NDIS facilities data were used and stored in the RDB MS. Then facilities attributes were stored in DB using data formed during 3D facilities DB building process and mapping the field video data. Finally, in the fifth stage, field construction scenes were filmed and classified into main construction process units. Then it was edited and stored in the facilities attribute information DB. Cuts must be no more than 5 minutes long and must include depth, grounding resistance, foundation structure,etc.

Fig. 2.6 Map and view of WoongCheun housing complex








CHAPTER 3

CASE STUDY OF FAULT PREVENTION MANAGEMENT
SYSTEM FOR THE UNDERGROUND FACILITIES

3.1 THE SCALE OF HOUSING COMPLEX DEVELOPMENT AND UNDERGROUND DISTRIBUTION FACILITIES PLAN

The residential development district on 2,800,000m2 seashore reclamation lot has three separate zones, and electric power must be supplied from a substation (7km away) to the residential district via pipelines. 8 new power distribution lines (22.7km) in the 1st phase are to be newly laid out at 22.9kV-y and 68,661 of power is to be supplied requiring new underground distribution equipment consisting of 56 manholes, 53 handholes and 46 switches.

3.2 CONSTRUCTION OF UNDERGROUND DISTRIBUTION FACILITIES AND PROCESS OF FILMING

Construction of underground distribution facilities are filmed for the segmented construction process by a digital camcorder. The shooting angle, required time, shooting location, etc. are agreed in a construction progress meeting. In carrying out UIS plan in the future, photographing and editing techniques perfected through several trials and errors could be very helpful.

3.3 MAIN SCREEN OF DEVELOPED SYSTEM

When construction of underground distribution facilities is completed, facilities data are stored in attribute DB, and the initial screen Fig. 7a shows the entire underground distribution facilities and actual site with menu based on the stored data. Construction date, constructor, types of structure and serial number can be searched from housing lot’s 109 kinds of underground facilities information transformed from the data in NDIS DB.


Fig. 3.1 Screenshots of developed system

As shown in Fig.3.1 (a) and Fig. 3.1 ©, it is feasible to measure the depth of the manholes and pipelines laid underground on the 3D screen and to check the conditions of the cable connections inside the manholes. In particular, detailed field information such as the soil of the excavation site, foundation settings and manhole assembly processes can be referred to through clips of the construction sites. Fig. 7d ˜ Fig. 7f show the underground facilities channel connected with manhole and cable. The system automatically carries out the planned inspection from connection point and grounding resistance of cable inside the manhole, then reports to the inspector 24 hours before the inspection day.

Table 3.1 Comparison of failure recovery time

.
3.4 COMPARISON OF FAILURE RECOVERY TIME

The time spent before the failure report and the time for engineers to arrive at the site, total recovery, switch operation by remote control, etc. had no difference. Before the introduction of the new system, it took 90 minutes for investigation of fault cause, initial construction condition, planning a recovery scheme and arrangement of necessary materials, but the new 3D GIS system reduced it to only 20minutes, saving an 70 minutes at maximum.








CHAPTER 4
CONCLUSION

The newly developed Construction and Management System for the Underground facilities could visualize underground distribution facilities using 3D GIS, so that everyone could check the present states and make full use of the detailed information. The failure caused by deterioration from omission of inspection is expected to be reduced as the new system makes underground distribution facilities application to be observed thoroughly and unexpected failure can be recovered quickly using the necessary information. The system can be a preceding research and is expected to contribute to the government’s UIS project, which mainly focuses on facilities such as gas, water/sewer, communication, roads, bridges, etc., which will be connected in a single network.


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