In a Test Laboratory, with the electrical installation and the installed transformer, voltage variations appeared and, sometimes, the electric current was interrupted by the loads that were required. The objective was to reduce the cost of the energy consumed in order to be more efficient in its use.
Situations to solve
- Eliminate voltage variations to avoid damage to installed equipment, since the cost of repairing equipment is high.
- Reduce costs: in case of interruption of the electric power, with the samples in the process, it was necessary to restart the test.
- Improve the electrical installation in order to avoid energy losses.
Transformer replacement analysis
- Because the installed transformer was out of service, the electric service supply was direct from the Federal Electricity Commission (CFE) network.
- Because of the location of the laboratory in an industrial park, there were frequent voltage variations.
- The Classification 02 rate contracted is more expensive than the OM Rate (which is obtained when installing a high-efficiency transformer).
Analysis of changes in the electrical installation
- The electrical installation had no connection to ground, which could cause electric shocks.
- The objective of a good grounding is not only safety; it also serves to prevent damage to equipment and industrial plants. A good grounding system will improve operational reliability and reduce the possibility of damage due to lightning or fault currents.
- The identified technical problems may result in:
- The danger of electric shock.
- Increase in the amount of billing.
- Greater consumption of electrical energy.
- Increase in losses in drivers.
- Premature wear of the drivers.
- Overload in the distribution lines.
- Increase in voltage drops.
- Damage to installed equipment, generating high operation and repair costs.
Regulations to comply
It is important that the transformers comply with the current regulations because this guarantees that the product complies with the requirements of the CFE, and so it can authorize the corresponding permits to carry out its installation. The rules to be met are the following:
Electrical System Protection
- NOM-002-SEDE / ENER-2014, Safety and energy efficiency requirements for distribution transformers.
- NOM-114-SEMARNAT-1998, Environmental protection specifications for planning, design, construction, operation, and measurement.
- NMX-J-285-ANCE-2013, pedestal, single-phase and three-phase transformers for underground distribution.
- CFE-K-0000-04, single-phase pedestal transformers up to 100 kVA for underground distribution.
Advantages of installing a high-efficiency transformer
- Minimum space requirement.
- More secure: by not presenting energized parts accessible to people, it can be installed in public places with restricted access.
- It constitutes a complete substation.
- Minimal maintenance due to contamination.
- Self-protected: power disconnection quickly and safely.
- Ease of service restoration after a failure in the secondary (only when it has a thermomagnetic switch).
- Nice aesthetic appearance.
Changes in electrical installation
According to the diagnosis made, a ground system was installed in the structure of the transformer and equipment: circuit breakers, fuses, disconnections, restorers, blades. Caliber No. 2 copper cable was used and the copper rod was installed by means of flux welding Type Cadwell No. 90. Changes were made to the electrical installation to harmonize the linear load: copper cable was used, the most suitable for this task. This prevents equipment damage and maintains constant voltage throughout the installation.