Identify the INCORRECT feature of static VAR compensator of EHV transmission system?
Low maintenance cost
Static VAR Compensator (SVC) Features in EHV Transmission
The question asks to identify the feature that is INCORRECT for a Static VAR Compensator (SVC) when used in EHV (Extra High Voltage) transmission systems. Let's analyze each option based on the known characteristics of SVCs.
Analyzing Static VAR Compensator (SVC) Options
- Poor reliability factor: SVCs use power electronics (thyristors) along with passive components (reactors, capacitors). While solid-state components generally improve reliability compared to mechanical devices, the complexity of control systems and potential failure modes of power electronics can sometimes impact overall reliability compared to simpler solutions like fixed capacitor banks. However, describing it as "Poor reliability factor" might be debatable and relative.
- Lower speed of response: SVCs provide dynamic reactive power compensation. They are much faster than mechanical switching devices or synchronous condensers in responding to voltage changes. Their response time is typically in the range of milliseconds (cycles of the power frequency). Compared to the latest technology like STATCOMs (which are voltage-source converter-based), SVCs are considered to have a slightly slower response due to the inherent delay in thyristor firing control. So, "Lower speed of response" could be considered true if comparing to STATCOM, but false if comparing to older technologies. The phrasing is ambiguous.
- Low maintenance cost: SVCs are complex systems involving power electronic valves (thyristor valves), cooling systems, control systems, transformers, reactors, and filter banks. These components require regular inspection, maintenance, and potential replacement, especially the thyristor valves and cooling systems. Therefore, the maintenance cost of an SVC is generally considered to be relatively high compared to simpler static compensation methods like switched capacitor or reactor banks.
- Reduced power system oscillation: SVCs provide dynamic voltage support. By quickly injecting or absorbing reactive power, they help in damping power system oscillations and improving system stability, especially transient stability and voltage stability. This is one of the significant benefits and applications of SVCs in EHV systems. This is a correct feature.
Identifying the INCORRECT Static VAR Compensator Feature
Based on the analysis, the statement that is most clearly an incorrect feature of a Static VAR Compensator is "Low maintenance cost". SVCs, due to their complex nature and reliance on power electronics and associated systems, typically have higher maintenance costs than simpler alternatives.
| Feature | Applicability to SVC | Correct/Incorrect Statement |
|---|---|---|
| Poor reliability factor | Debatable/Relative; generally considered reliable among dynamic compensators but complex | Potentially incorrect depending on comparison |
| Lower speed of response | True compared to STATCOM; False compared to mechanical methods | Ambiguous, context-dependent |
| Low maintenance cost | False; typically high due to complexity | Incorrect Statement |
| Reduced power system oscillation | True; SVCs provide damping | Correct Statement |
Therefore, the incorrect feature listed among the options is "Low maintenance cost".
Important Questions from Voltage Control
Which component(s) is/are required to obtain a proportional DC voltage for a voltage sensing relay?
Shunt reactors are sometimes used in high voltage transmission system to
The complex power consumed by a constant – voltage load is given by (P1 + jQ1), Where, 1 kW ≤ P1 ≤ 1.5 kW and 0.5 kVAR ≤ Q1 ≤ 1 kVAR.
A compensating shunt capacitor is chosen such that |Q| ≤ 0.25 kVAR, where Q is the net reactive power consumed by the capacitor – load combination. The reactive power (in kVAR) supplied by the capacitor is__________.For enhancing the power transmission in along EHV transmission line, the most preferred method is to connect a
Which of the following is the function of static var system in EHV transmission?
