Misuse of Indian standards and Propaganda Business (e.g. Large metro rail project)
- VIDYUT SURAKSHIT BHARAT ABHIYAN
- Jul 9, 2022
- 3 min read
Updated: Jul 9, 2024
Several large-scale projects in India, non-standard methods are being used in subjects related to electrical safety, and reliability. Compliance to national regulations are violated.
One classic example is the use of Earthing in metro rail projects. The following case study is from the tender documents of a leading metro rail.
Tender specification
Tender specifications can be downloaded from the following links.
Note: refer the tender specifications and calculations included in the above documents to understand the below figure.
According to the calculations included in the tender, an earth fault in Low Voltage powerline (230 volt) produces a GPR of above 15kV. Two large sized earth mats are constructed under the metro railway station, one for LV electrical system and another for clean earth.
Note: GPR is Ground Potential Raise, means the voltage between the faulty place and remote earth.
The system recommended in the tender violates not only the Indian standards, but all standards mentioned in the tender. The tender specification looks like a collection of fancy sentences from several standards.
Video about the subject presented before 250 + participants can be viewed below.
In these metro rail projects where the soil resistivity is about 30 ohm-M (highly corrosive soil) tons of earth enhancing compounds are also used.
This tender is a classic example of believing the propaganda of software companies who promote IEEE80.
The propogandists fail in informing the customer that
IEEE80 is a Guide. Not an IEEE standard or a recommended practice.
IEEE Guides are documents in which alternative approaches to good practice are suggested but no clear-cut recommendations are made.
Definition of substation in USA is different than what we generally use in India.
IEEE 80 is educated as the Holy solution for all earthing problems in India, irrespective of the operating voltage, which leads to big mistakes in projects of national interest.
For more information on various IEEE documents read IEEE SA - Standards Board Operations Manual – Clause 1
Some highlights from the tender specification are as below,
1. A grid as per IEEE 80 is constructed underground and is used for Low Voltage application.
Comment: This is ridiculous.
2. The soil resistivity mentioned is 30 ΩM. The earth electrodes are to be encased with earth enhancement material of 0.12 ΩM.
Comment: This enhancement material only increases the corrosion of the electrode. 30 ΩM itself is a low resistivity and is of highly corrosive in nature.
3. The drawings show the conventional “TWO FOR NEUTRAL, TWO FOR BODY”. This is shows the unawareness of the designer.
Comment: The designer not only violate the standards mentioned in the tender but provide a wrong and bad impression about the standards and regulations of India.
Unfortunately, such wrong tender specifications once created will be followed in several projects, for decades without any scrutiny. This system once installed underground cannot be rectified again, which means the metro rail shall live with this junk for its lifetime. These installations survive due to mere luck rather than reliability.
As the first corrective step, all designers shall strictly follow IS standards, if not IEC standards as recommended in the current CEA safety regulations.
Conclusion:
The above referred tender specification is a complete violation of Safety Regulations of Govt of India. The users (metro railways) shall have some mechanism to penalise the designers for wrong designs and get compensation from them. Remember similar design is followed in several projects.
blog by
S. Gopa Kumar
Campaign Director
gk@vidyutsuraksha.com
member
IEC - TC64: (Safety, Protection against shock) MT 3, MT 12, MT40, MT 41, PT 60364-8-3, WG 43
TC81: (Lightning protection) ahG 19, MT 3, MT 14, MT 21, WG 18
SC 37 A: (L V SPD’s) WG3 & WG
BIS - National Building Code-2016 (electrical committee),
ETD 20 (NEC, IS732, IS3043), ETD 30, ETD 50
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