How to Quickly Identify Whether Your Customer Needs SVG or AHF?

When dealing with Power Quality Products, one common challenge salespeople face is determining whether a client should go for an SVG (Static Var Generator) or an AHF (Active Harmonic Filter). At first glance, both devices may appear similar—they are often rack-mounted, serve power correction functions, and connect at low voltage levels. However, their purposes are distinctly different.

Misunderstanding this distinction can lead to poor recommendations, underperformance on-site, or missed opportunities. This guide is here to help you—especially if you're in sales or technical pre-sales—quickly determine the right product based on the customer's problem, load type, and target.

Step 1: Listen Carefully to What the Customer Is Saying

Most customers won’t use technical terms like “reactive power” or “Harmonic current.” Instead, they’ll describe the symptoms they’re experiencing. Here's a practical way to map customer complaints to the right solution:

Quick takeaway:
- If the issue is power factor, recommend SVG.
- If the issue is distortion or interference, recommend AHF.

Step 2: Understand the Load Type

Knowing the customer’s load profile will give you a clear indication of the power quality issues they’re likely facing.

Step 3: Confirm the Customer’s Objective

The customer's real motivation determines the product type and sizing strategy. Ask:
- Are they trying to eliminate penalties?
- Do they want to pass inspections based on THDi/THDv levels?
- Are they seeking long-term energy optimization?
- Is budget a constraint?

Step 4: Use Simple Sizing Methods to Recommend Capacities

AHF Sizing: Two Practical Methods

(1) Centralized Harmonic Governance (Based on Transformer Capacity)
   Ih = (S × K) / (√3 × U × √(1 + THD²)) × THDi
   Where:
   - S = Transformer capacity (kVA)
   - K = Transformer load rate (typical: 0.6~0.8)
   - U = Line voltage (V)
   - THDi = Target harmonic current distortion rate

(2) On-Site Governance (Based on Load Devices)
   Ih = K × In × (THDi / √(1 + THDi²))
   Where:
   - In = Rated current of the main load
   - THDi = Measured or estimated harmonic current content

SVG Sizing: Two Methods

(1) Based on Transformer Capacity:
   Qcomp = 30% × S

(2) Based on Power Factor Correction:
   Qcomp = P × (tanθ1 - tanθ2)

Real-World Example

Let’s say your customer runs a chemical plant with a 2000 kVA transformer, 70% loading, and measured THDi of 35%.

AHF capacity estimate:
   Ih = (2000 × 0.7) / (√3 × 400 × √(1 + 0.35²)) × 0.35 ≈ 700 A
   → Recommend two 400A AHF modules in parallel.

SVG capacity estimate:
   Q = 30% × 2000 = 600 kvar
   → One 600 kvar or two 300 kvar SVG modules.

Step 5: Don’t Be Afraid to Recommend Both

In many real-world scenarios—especially in plants with high harmonic loads and low power factor—one device alone won't do the job. That’s why many advanced systems use both SVG and AHF in tandem, sometimes even integrated into one cabinet.

For example:
- AHF filters 5th, 7th, 11th harmonics
- SVG boosts the power factor from 0.7 to 0.95

This combo ensures clean, stable, and efficient power delivery—something utility companies love and clients appreciate.

Final Thoughts

You don’t need to be an engineer to recommend the right solution—you just need to ask the right questions and understand the basics of how these devices work.

By following this guide:
- You’ll sound more professional
- Help your client make informed decisions
- And most importantly—increase your chances of closing the deal