## 3 New Concept for Assessing the Technical Condition of HV Switching Bay Devices
### A New Concept for Calculating the Technical Condition of a Circuit Breaker
#### 3.2.2 Additive Criteria for Calculating the Technical Condition of a Circuit Breaker  
Table 4 presents the concept of nine additive criteria encompassing a CB's operating history. Criterion \(CR_{1}\) is related to the total number of all deficiencies and internal defects detected in the CB throughout its entire operating period. The cumulative number includes all types and levels of defects, except those that render the CB in \begin{table}
\begin{tabular}{l l l l l l l l} \hline \hline
**IT Main Group (i)** & \(j\) & **Description** & **Task** & **Initial Cause** & **Measure** & \(RDID\) & \(RPL\) \\ \hline Auxiliary Deficiency/Internal Defect & & & & & & & \\ \hline \(DID_{1}\)\({}^{\text{A}}\) & Grounding system & 1 & Damaged & SI & Mechanical defect & Grounding repair & 2 & 0 \\  & & 1 & Damaged & SI & Mechanical defect & Structural remediation & 2 & 0 \\ \(DID_{2}\)\({}^{\text{A}}\) & Supporting structure & 2 & Corrosion of & SI & Structural corrosion & Corrosion remediation & 1 & 0 \\  & & & metal parts & & & & & \\  & & & Inadequate connection & & & & & \\  & & 3 & of the device to & & GC, SI & Mechanical defect & Device attachment & 3 & 0 \\  & & & the structure & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont._that the state returns to its previous value after remedial action. However, in the new concept, as the deficiencies and internal defects are eliminated, the state is no longer the same as prior to the remedial action. The weight of this criterion is medium, with \(w_{1}=4\). The grades are distributed discretely. Criterion \(CR_{2}\) is related to the total number of detected DIDs on the CB throughout its entire service lifetime. Sometimes, a specific type of DID may be detected more than once during the CB's service lifetime. This criterion penalizes such occurrences. The criterion is divided into four categories, with increasing repetitions of the same type of DIDs resulting in a decrease in grades. The weight of this criterion is medium, at \(w_{2}=4\). Criterion \(CR_{3}\) is related to the total number of DIDs detected in the CB throughout its entire operating period. DIDs detected and eliminated in the distant past have a smaller impact on the condition of the CB than those detected more recently. The criterion is divided into four categories, with older detected DIDs receiving a higher grade for this criterion. The weight of this criterion is medium, \(w_{3}=4\). Criterion \(CR_{4}\) is related to weather and environmental influences. The effects of wind (such as pollen deposition on the CB insulators) and the contamination of the insulators are not necessarily covered by detected deficiencies, which affects the subsequent cleaning of the insulators. The probability of wind and contamination influences can be determined in advance for each substation location by classifying the location into one of four categories (each substation has a different grade). This classification determines the category grade of the criterion, which does not change. The influence on the final grade is small; the agreed weight is \(w_{4}=2\). The grade of this criterion is determined, and it aligns with expert judgment. Figure 3: (a) General flow chart for calculating the multiplicative criterion grade \(GCR_{-1}\) for a circuit-breaker, disconnector, and instrument transformer; (b) general flow chart for calculating the grade (\(GCR_{-2}\)) for multiplicative criterion \(CR_{-2}\) for an instrument transformer. Criterion \(CR_{5}\) is the most essential criterion among the set of criteria from \(CR_{1}\) to \(CR_{9}\). The in-service time of a CB is known and tied to its location. A partial grade can be determined from these data. This grade may indicate undetected hidden deficiencies and internal defects that are indirectly related to age (e.g., mechanical fatigue of the material). The grade value of a CB at an age within this range is calculated using linear interpolation with fixed discrete grades.