I am wondering why the LMZ current transformer gets selected over and over for the MEA/PEA project, in Thailand.

If you’ve worked on power projects in Thailand, you’ll likely encounter two names:

MEA (Metropolitan Electricity Authority) and PEA (Provincial Electricity Authority).

In my work, on the power distribution renovation in downtown Bangkok and the transformer upgrade in provinces I see that the requirements of the two organizations for transformers are, from an engineer perspective. The current transformers do not need features. The current transformers must be stable must be durable must be easy to use and must be easy to maintain.

That is why engineers use transformers such, as the HYLMZW4 for projects in Thailand. Current transformer such as the HYLMZW4 are now common, in Thai projects.

Let us talk about the reasons. Let us look at the reasons, from the view of the “construction site”.

一、The world working conditions of MEA/PEA projects show one thing: excessive use. The world working conditions of MEA/PEA projects are use.

Let us start with the environment.

I notice that Thailands power system has characteristics.

High temperature: 30℃+ year-round, with even higher temperatures inside the distribution cabinet.

High humidity: coastal areas, rainy season, humid air

Large load fluctuations: mixed use of commercial, residential, and industrial areas

Low maintenance frequency: Install once and expect to stay in place for many years.

I think the meaning is that if a current transformer:

• Insufficient insulation
• Poor temperature rise control
• Precision drifts at high temperatures

I think the team will phase out the MEA/PEA project soon. The team will stop using the MEA/PEA project. From my perspective the team will phase out the MEA/PEA project soon because the MEA/PEA project no longer fits our goals.

1.Why is the LMZ (HYLMZW4) structure a perfect match for MEA/PEA?

50/60Hz full coverage, directly compatible with Thai systems.

I have found the HYLMZW4 works for 50–60Hz power systems. The HYLMZW4 is built for those frequencies. When I connect the HYLMZW4 to a 50–60Hz power system the HYLMZW4 runs reliably.

Thailand’s standard frequency: 50Hz

Sometimes the projects need the compatibility. The compatibility is, with the imported equipment (60Hz).

For engineers, saving time and effort is the key, as there’s no need for frequency customization.

2.A temperature range of -40℃ to 85℃ is truly “friendly” to the tropics.

I have seen the temperature, inside the electrical control cabinet rise higher than you think. I have felt the temperature, inside the electrical control cabinet get hot.

The ambient temperature range for the LMZ current transformer is:

-40℃ to +85℃

I have found two practical implications affect the Thailand project:

I notice that high humidity and high temperature, during the season keep the insulation stable. The insulation stays stable.

Long-term operation inside the cabinet → Precision is less prone to drift

I think the approach matches MEA/PEA preference, for term stability.

3.The main current range is 100 to 400 amps. The main current range covers the needs of the power distribution side.

Typical application scenarios, for the MEA/PEA include:

Low-voltage side of distribution transformer

Outgoing circuit current detection

Load monitoring and metering auxiliary

And 100A–400A is exactly:

Urban power distribution

Industrial and commercial users

small transformer

The most common current range.

Engineers love balance. The balance is not over-sized and not under-sized.

4.With 0.5 class accuracy and 5 VA output the device measures accurately. The device can handle demanding conditions.

I notice that many projects are not, at the measuring bureau level of precision. I also notice that many projects have data reliability requirements.

The LMZ configuration looks like this:

• Accuracy class: 0.5
• Secondary current: 5A
• Load: 5VA

The approach brings advantages to the Thailand project:

I tested the system. The system can drive instruments relay protection and data acquisition modules reliably.

I notice that errors do not happen easily because of load changes. When the load changes the system stays steady. Errors are rare.

More worry-free during the debugging phase

For engineers, avoiding problems is more important than having good-looking parameters.

5. 4kV power frequency withstand voltage, meeting the minimum safety requirements of MEA/PEA.

In power bureau projects, insulation and safety are “hard requirements”.

The key features of HYLMZW4 include:

• Primary/Secondary withstand voltage: 4kV / 1min
• Insulation resistance ≥1000MΩ (500V DC)

This means:

The risk of leakage is low in high humidity environments.

Secondary side equipment is safer

The project acceptance process is easier to pass. I have found that project acceptance is easier to pass when you follow the checklist.

One of the conditions also says that the project must be, in the MEA/PEA project list. The project must meet the condition.

Third, from an engineer’s perspective: its biggest advantage is actually “less worry”.

Many engineers share a consensus:

I have found the good current transformer is not the transformer, with the specs. The good current transformer is the transformer that I do not need to worry about after I install the transformer.

I have seen this. From my view the advantages of the LMZ series, in the Thailand project are shown in:

• Simple structure, not delicate
• The installation logic is clear.
• Stable long-term operation
• Not easy to repair

This is crucial for large-scale public power systems like MEA/PEA.

In summary

The HYLMZW4 current transformer is liked by the MEA/PEA, in Thailand not because the HYLMZW4 current transformer looks flashy. I have seen the HYLMZW4 current transformer work steady and reliable, in the power environment of Thailand. Thailand’s power environment has temperature, high humidity and high load. The HYLMZW4 current transformer handles those conditions without worry.

Compay：HEYI Electrical Co., Ltd.

Brand: HEYI/ASCT

Contact: Bethy

E-mail: heyi@heyiele.com             

Tel: 86-13968747975

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