Case Study

Case 1: The Mall, Kuala Lumpur

Building struck by lightning below the edge of The Mall, Kuala Lumpur. No conventional or unconventional lightning protection system available close to the stricken. But, The Mall is actually attached to Legend Hotel where there is ESE air terminal installed on top of the building as shown in the Plate no: 1.

Plate No: 1: Lightning struck below the edge of the roof at The Mall, Kuala Lumpur where that area is not protected by lightning protection system.

Case 2: SuCasa Service Apartment, Jalan Ampang, Kuala Lumpur

Lightning struck at a roof structure of the building, and there are 2 locations of lightning strike points adjacent to each other.

Plate No: 2 The sharp edges of the building experienced damages

Case 3: Grandeur Tower, Ampang

Building in the same locations badly damaged by lightning struck (refer to Plate No3 ). Notice the same location of the lightning struck at the corner of the roof and the pointed roof structure, showing poor lightning protection system installed or probably no lightning protection installed on top of the roof. One is unable to locate any conventional or unconventional lightning protection system. Almost 70% of the sharp edges of this building being struck by lightning. From the condition of the damages there is a possibility of multiple struck were repeatedly occurred.

(a)


(b)

Plate No 3 :The sharp edge of the building experienced lightning related damages i.e lightning struck at the corner section of a roof at Grandeur Tower, Ampang for case (a) and (b).

Case 4: Bangunan Risda, Jalan Ampang

Building struck by lightning at the corner roof structure, the ESE air terminal installed about 30metres away at the highest location from the corner roof structure. Air terminal is not effective in providing sufficient protection on all the roof structure.



Plate No 4: Lightning struck at the corner section of a roof at Bangunan Risda, Kuala Lumpur. ESE air terminal installed at the highest point of the building, but unable to protect the edge of the building


Case 5: Bukit Rawang Jaya Apartment


Plate No 5: Lightning struck at the gable of the roof at Bukit Rawang Jaya apartment notice Franklin rod at the edge of the roof.



Case 6: Low-cost Apartment in Kuantan, Pahang
Damaged at the top of the building and far from the protection rod.


Plate No.6: Lightning struck at the gable of the roof at a apartment in Kuantan


Case 7: Lafarge Building, Kuala Lumpur.


Lightning related Damaged at the edge of the building but surprisingly that spot is very near to the protection rod.



Plate No.7: Lightning struck at the sharp edge of the building top overlooking it is the Franklin Lightning Rod



Case 8 Kuala Lumpur General Hospital



Physical damage at the edge of the building leaving a chisel like edges


Plate No. 8: Lightning struck at the roof edge of Kuala Lumpur General Hospital


Case 9: Flextronics Building, Johore Bahru



Plate No.9: Lightning struck at the parapet wall of Flextronics.



The physical damage is quite serious where a big chunk of the building wall has fall off the building.



Case 10:Shop Houses, Nilai, Negeri Sembilan.

Plate No.10: Lightning struck at the concrete slap of the building top

Case 11: Multi-storey apartment, Kuantan, Pahang

Plate No. 11: The roof tiles were flown away and damaged due to lightning strike


Case 12: Building in Kuala Lumpur

(a)


(b)

Plate 12: a) A close-up new of the building parapet wall damaged due to lightning strike b) vertical closed-up view of lighning related damad

Types of Grounding

1. Ungrounded.

Electrical power systems that are operated with no intentional connection to earth ground are described as ungrounded. Although these systems were standard in the '40s and '50s, they're still in use today. The main advantage of this type of grounding system is that it offers a low value of current flow and reliability during a fault. Unfortunately, this type of system also offers some big disadvantages. One major disadvantage to an ungrounded system is in the difficulty in locating a line-to-ground fault. Finding the fault is a time consuming process. For that reason, it's often done on the weekends so a company doesn't have to shut down its normal production processes. In addition, the fault must be located and repaired quickly because if a second fault occurs, the fault acts like a phase-to-phase fault extending the repair process.

Advantages


•Offers a low value of current flow for line-to-line ground fault (5A or less).
•Presents no flash hazard to personnel for accidental line-to-ground fault.
•Assures continued operation of processes on the first occurrence of a line-to-ground fault.
•Low probability of line-to-ground arcing fault escalating to phase-to-phase or 3-phase fault.
Disadvantages


•Difficult to locate line-to-ground fault.
•Doesn't control transient overvoltages.
•Cost of system maintenance is higher due to labor involved in locating ground faults.
•A second ground fault on another phase will result in a phase-to-phase short circuit.

2. Solidly grounded.

This type of grounding system is most commonly used in industrial and commercial power systems, where grounding conductors are connected to earth ground with no intentional added impedance in the circuit. A main secondary circuit breaker is a vital component required in this system, although it has no bearing in other grounding systems. This component is large in size because it has to carry the full load current of the transformer. Back-up generators are frequently used in this type of grounding system in case a fault shuts down a production process. When this happens, the generators become solidly grounded. However, it's important to note that the generators aren't designed for the larger short circuit current associated with solidly grounded systems.

A solidly grounded system has high values of current ranging between 10kA and 20kA. This current flows through grounding wires, building steel, conduit, and water pipes, which can cause major damage to equipment and shut down production processes. When a line-to-ground fault occurs, arcing can create flashes-generally in the terminating box. In this enclosed area, water is turned to steam, causing the terminating box. To locate the fault, all you need to do is follow the smoke.

Advantages


•Good control of transient overvoltage from neutral to ground.
•Allows user to easily locate faults.
•Can supply line-neutral loads.
Disadvantages


•Poses severe arc flash hazards.
•Requires the purchase and installation of an expensive main breaker.
•Unplanned interruption of production process.
•Potential for severe equipment damage during a fault.
•High values of fault current.
•Likely escalation of single-phase fault to 3-phase fault.
•Creates problems on the primary system.

3. High-resistance grounding.

High-resistance grounding (HRG) systems are commonly used in plants and mills where continued operation of processes is paramount in the event of a fault. High-resistance grounding is normally accomplished by connecting the high side of a single-phase distribution transformer between the system neutral and ground, and connecting a resistor across the low-voltage secondary to provide the desired lower value of high side ground current. With an HRG system, service is maintained even during a ground fault condition. If a fault does occur, alarm indications and lights help the user quickly locate and correct the problem or allow for an orderly shutdown of the process. An HRG system limits ground fault current to between 1A and 10A.

Advantages


•Limits the ground fault current to a low level.
•Reduces electric shock hazards.
•Controls transient overvoltages.
•Reduces the mechanical stresses in circuits and equipment.
•Maintains continuity of service.
•Reduces the line voltage drop caused by the occurrence and clearing of a ground fault.
Disadvantages


•High frequencies can appear as nuisance alarms.
•Ground fault may be left on system for an extended period of time.

Introduction: Assignment 1

Background:
MMSC Consultancy was established to study based on the case study given, why grounding system failed to provide protection and had caused a physical damaged to commercial and residential building. This project is under supervision of Prof. Hussien Ahmad, director of IVAT from UTM Malaysia.


MMSC Consultancy member's:
1. Mohd Hayriel Salim (TL)
2. Chong Kiat Shiu
3. Siti Aishah Bakar
4. Mariam Mat Saad
All members are currently pursuing a Master in Electrical Engineering.

Objective of the assignment:
1. To investigate why Franklin Rod failed to capture the lightning.
2. Explanation on edge surface is more prone to lightning strike.
3. Based on the study, to provide a recommendation to avoid the repeated fault.

Strategies:
1. To do measurement on the grounding system.
2. To check soil resistivity at the location.
3. To indentify class of protection installed on the building using angle of protection and rolling sphere.
4. To investigate the root cause that reduces the effectiveness of the Franklin Rod. i.e: copper degradation and cable theft.

Delegation:
1. Hayriel – Logistic
2. Chong – Equipment
3. Aishah – Documentation
4. Mariam – Theoritial