The Nigerian Electricity Management Service Agency (NEMSA) has issued a warning against the influx of substandard transformers into the country, saying that this has caused many challenges in the industry.

 Its managing director and chief electrical inspector of the federation, Engr. Peter Ewesor revealed this at a press conference in Abuja yesterday.

In this context, he informed all stakeholders in the power industry, federal and state ministries, departments and agencies, as well as the public engaged in power and power project implementation in Nigeria, that the allowable transformer Vector Group specifications are in the current Nigeria power supply and installation standards (NESIS).

 Ewesor said: "Recently, we have discovered a lot of ongoing activities that are beneficial to health, so I will start with our recent enforcement notice on certain issues. First, it is about the transformers that are fully embedded in NESIS that are allowed to be used in Nigeria by law. Type and quality.

"These regulations clearly stipulate that for distribution transformers, transformers used in the distribution electronics industry, from 50KVA to 2,500KVA, they must have a Vector Group called Dyn11. It has a reason, and it has a purpose. "For distribution electronics The power transformer of the industry, 2,500KVA-3,000KVA power transformer must be Dyn1. Before formulating these regulations, a lot of analysis has been done, because there is what we call a phase sequence between power generation, transmission and distribution.

"But we have recently discovered that many transformers entering the country actually do not meet the requirements and standards.

"Basically, these transformers will cause a lot of harm in the industry. Some of them generate what we call harmonics, which can heat the electrical materials and equipment in the house; some of them have internal faults and internal problems, which generate heat inside the transformer, Make transformers explode and cause danger; some of them are actually called what we call special transformers, and they are designed to be used in special ways in certain installations. But we found that these products have entered the country and brought Many challenges."

 Ewesor further explained that the standard power transformer (TS) capacity should be 2.5MVA, 5VVA, 7.5MVA and up to 30MVA, which he said is suitable for 33/11KV operation, the secondary side of the transformer is 11KV, the nominal frequency is 50Hz and the vector group Dyn1.

 He emphasized that the distribution transformer should be 25KVA, 50KVA, 200KVA, 500KVA, 1000KVA, 1500KVA and 2500KVA. He said that it is suitable for 33/0.415KV or 11/0.415KV operation. The vector group with a transformer rated frequency of 400V 50Hz is Dyn11.

 The general manager revealed that all special transformer vector groups not accepted by Nigeria distribution transformers include Dyn5, Zig-zag, Yyn0, Ydn11 and YNyn0d1.

 Ewesor also announced a nationwide ban on the use of 33KV primary feeders from substations to 33/11KV injection substations for point load transmission.

 According to him, the reasons include unnecessarily increasing the line load of 33KV-H feeder/11KV injected into the substation, emphasizing that most customers on the 11KV-0.415KV network will be deprived of adequate and reliable power supply.

 He also explained that the 33KV point load location is a potential failure point along the 33KV primary feeder, causing frequent trips of power lines and power system equipment, resulting in frequent interruptions/smooth power flow to users/consumers.

 Ewesor said: "There are difficulties in maintenance work along the overhead feeders, which will inevitably increase the number of intersections of 33KV and 11KV overhead feeders.

"It also created too many kick-off points in the 33KV main feeder or the instability of the distribution network."

 Ewesor stated that the "deduction" of inappropriate transformer vector groups is not an excuse for non-compliance with the current regulations, saying that it will derogate installations that do not comply with the current regulations and bring such installation compliance within the specified time. sex.

He made it clear that the derogations do not apply to new devices, because these devices must first comply with the current NESIS regulations when they are conceived/started before they can be implemented.

The agency also warned electricity consumers to pay attention to unqualified and uncertified meters, and added that the meter certified by the agency has a plastic seal with NEMSA inscription to confirm that the meter has been tested and certified or used by NEMSA .