EE582: Power System Engineering 1

Design Project 2

SYSTEM PLANNING FOR GENERATION RETIREMENT

FINAL PROJECT REPORT

GROUP 7

Pithapur Mohammed (40)Cheruvattath Sneha (32)Tavadia Urvakhsha (45)

DESIGN CASE: TWO

DESIGN PROJECT 2

SYSTEM PLANNING FOR GENERATION RETIREMENT

DESIGN CASE DETAILS

After more than seventy years of service the SANDERS69 power plant is being retired. The situation requires meeting the electricity demand without building a new generator. As planning engineers we are required to recommend construction of new lines and transformers to meet these demands and to ensure that the transmission system in the MLP system is adequate for any base case of first contingency loading situation.

BASE CASE:

After loading and running the case, it was seen that the base case has a loss of 13.54 MW and has 13 violations.

Fig 1: Base Case in Power World Simulator

Fig 2: Initial Contingency analysis of Design Case 2: System Planning for generation Retirement.

The main aim was to not only to reduce the system losses and reduce the violations to zero but also to keep the solution as economic as possible.

We tried out various options and found the following three solutions to be quite suitable.

Solution 1:

Upgrade Wolen69 substation from 69kV to 138kV with the help of a 101 MVA transformer and install a new 138kV transmission line between SLACK and WOLEN.

Solution 2:

Installing three 69kv lines between

a) (i) Lynn & Scot (ii) Scot & Bob & (iii) Bob & Wolen and b) A shunt capacitor of rating 15 MVar on Bob 138.

Solution 3:

Setting up a new 138/69kV substation between WOLEN and LYNN.

Detailed analysis of all solutions are provided below

SOLUTIONSSOLUTION 1 (MOHAMMED PITHAPUR)

Upgrade WOLEN substation from 69kV to 138kV with the help of a 101 MVA transformer and install a new 138kV transmission line between SLACK and WOLEN.

Reason: The original case had multiple issues due to overloading of BOB138 bus as it was primarily supplying load to WOLEN 69 bus. After trying out various possible combinations, I found that adding a new transmission line from SLACK138 to WOLEN69 was the ideal choice since this combination reduces the power that BOB138 has to transfer.

For the above solution, I had two possible paths:

A. Installing a new 138/69KV transformer at SLACK138 and installing a new 69KV line from SLACK to WOLEN,

B. Upgrading WOLEN69 to WOLEN138 by and installing a new 69/138KV Transformer so that the Transmission line from SLACK to WOLEN would be at 138KV.

To find out the worthy solution, I performed simulations for both the cases using the following conductor parameters and tower configurations.

Case A: Rook Conductor with Tangent Single Pole (TS-1) Tower (Losses 12.44MW) (69KV line)Case B: Lark Conductor with Tangent Single Arm (TS 138) Tower. (Losses 11.74MW) (138KV line)

After thorough calculations in both the cases with different conductors and towers, I found that Case B is more feasible, since the losses are quite less.

Although we have to incorporate higher initial capital cost, the profits gained from the reduction of losses make Option B the best choice.

For Case A, the installation costs come out to be $3,375,000 and the profit due to losses is merely $2,409,000.

However, the total installation cost for Case B is $3,650,000. And the profit from losses is $3,942,000 for a span of 5 years.

Implementing Case B gives us a profit of $292,000 for 5 years. Case B is a feasible and economical solution.

Choices:

A. Right of way used SLACK to WOLEN (11.5 miles)B. Conductor Type LARK (600A)C. Tower Type TS-138 Tangent Single Arm (138 kV)

PARAMETERS

Fig 3: After calculating and inputting parameters

Results:

After implementing these calculations, the system showed a reduction in losses from 13.54MW to 11.74MW.

Fig 4: Reduction in losses

Furthermore, all the contingencies were eliminated.

Fig 5:Contingency Analysis with new design

Calculations

Transmission line cost (138KV) $200,000/mile

Total Transmission line cost (200000$/mile*11.5mile) $2,300,000

Fixed Line cost (138KV) $200,000.

Total Fixed cost for 138KV line $200,000.

101MVA Transformer cost $950,000.

Cost for upgrading WOLEN69 to 138KV $200,000.

Profit due to Loss Reduction for a duration of 5 years is

(8760hours*5years*$50/MWh*1.8MWh) = $3,942,000 (1)

Cost Analysis:

Particulars Cost

Total Fixed line installation cost $200,000

Transformer cost $950,000

Upgrading 138/69 KV Substation cost $200,000

Line cost according to Right of way $2,300,000

Total: $3,650,000 (2)

Profits after installation are : (1) - (2) $292000 Thus, after implementing the above solution, we gain a hefty profit of $292,000 in a

span of 5 years.

SOLUTION 2 (URVAKSHA TAVADIA)

The main aim was to not only to reduce the system losses and reduce the violations to zero but also to keep the solution as economic as possible. I tried out various solutions and decided to go with the solution presented below.

1. Three 69kv lines introduced between-- Lynn & Scot (12 miles) (with a 101 MVA transformer).- Scot & Bob (8.5 miles).- Bob & Wolen (4.8 miles).

2. Shunt capacitor of 15 MVAR on Bob 138.

Reason:

I did find another solution which was-- Scot to Jo (With transformer).- Scot to Bob.- Scot to Sanders.

However the system losses were 13.14, higher in comparison to the selected solution as well as the total cost was significantly higher.Also I had to select the conductor Partridge, even though it has a real high resistance, to keep the costs low.

Choices:

Right of way used 25.3 milesConductor Type PARTRIDGE (460A)Tower Type Medium and large vertical angle (69 kV)

Parameters:

Fig 6: Transformer ratings.

The specifications are as per the ratings specified in the project document. A transformer is placed between Lynn and Scot. The transmission line selected is a 69kv transmission line. Calculations were done and the 69kv line was found to be more economical than the 138kv line.The Resistance, Inductance and Capacitance specifications are in accordance to the type of conductor and tower selected.

After observing the violations, transmission line between Scot and Bob & Bob to Wolen was introduced.

Fig 7: Scot to Bob Transmission Line.

Fig 8: Bob to Wolen Transmission Line.

The violations were reduced from 13 to 2. The last 2 violations were removed by placing a shunt capacitor of 15 MVAR on BOB 138.

Fig 9: Shunt Capacitor on Bob 138.

Results:

After making the above mentioned changes, the system losses were reduced to 12.84MW from 13.54MW and the violations were reduced to 0 from 13.

Fig 10: System Losses reduced to 12.84MW.

Fig 11: The violations are reduced to 0.

Calculations:

Transmission line cost (69kv)/mile- $111,428.

Fixed Line cost (69kv)-$125,000.

Total Fixed cost- 125,000 X 3= $375,000.

Transformer cost- $950,000.

New 138/69kv substation cost- $400,000.

Line cost according to Right of way=(12+8.5+4.8) X 111,428= $2,819,128.4.

Shunt Capacitor (15 MVAR)= $ 37,500.

Cost Analysis:

Particulars Cost ($)Total Fixed line installation cost 375,000Transformer cost 950,000New 138/69kv substation cost 400,000Line cost according to Right of way 2,819,128.4Shunt Capacitor (15 MVAR) 37,500Sub Total 4,581,628.4Loss reduction cost -1,533,000TOTAL 3,500,256.8

SOLUTION 3 (SNEHA CHERUVATTATH)

Setting up a new 138/69kV substation between WOLEN and LYNN, shunt at HISKY and a shunt at SANDERS.

Reason:

After trying out various solutions I decided to design the system with a new 138/ 69-kV transformer. The contingency analysis showed that there were no violations. To further reduce losses and cost it was essential to determine whether it is better to consider the transformer on the 69 kV line or the 138 kV line. Initially per unit parameters for both lines were. For example I considered IBIS and PIPER conductors for the LYNN line and Cardinal and Crane for the WOLEN line. From this I realised that 69kV line has lesser loss and costs. But there were still a few contingencies. So after considering further cases with different towers and conductors and the optimal solution was using the CONDOR conductor which reduced the loss considerably to 12.99MW. After that there was no contingencies. To further reduce the losses I added a shunt to HISKY as well as SANDERS which reduced losses to 12.69 and hence making it more economical.

Choices:

Right of way used 15 milesConductor Type CONDOR (670A)

Tower Type Tangent Horizontal Line Post(69 kV)

Parameters:

Fig 12(a): Inputting parameters for the line

Fig 12(b): Inputting parameters for the transformer

Results:

After running the system with the new parameters the losses came down to 12.69 MW.

Fig 13: Reduction in losses

The contingencies also were eliminated.

Fig 13: No contingencies

Cost Analysis:

Particulars Cost ($)

Total Fixed line installation cost 125,000

Transformer cost 950,000

Shunt capacitance Cost 200,000

Line cost according to Right of way 1875000

Loss reduction cost difference 1,216,400

Total $

Conclusion:

The main aim of the project is to make the system self-sustainable. Initial contingency analysis gives us a broader view of current system issues. Addressing them in a technical way and bringing out the most feasible solution by meticulous selection of parameters was the priority. Though setting up of new transmission line or substation isn’t as extensive as an entire power plant, it still demands the same attention to detail and performance parameters. The three critical factors on which we have emphasized our solutions are – Reliability, Reduction in Losses and Cost. WOLEN69 is the most affected bus due to unavailability of SANDER69 generator. The load at this bus being very high, it made sense to provide an alternate path for WOLEN69.

After going through various possible solutions, we ended up on the following three. SLACK138 has two generators at one end. Given the right of way SLACK to WOLEN, constructing a transmission line would be beneficial (Solution-1). LYNN138 hardly carries any load during normal circumstances. Hence, adding a new line from LYNN to WOLEN, given the right of way was also a great option (Solution 3). Both the solutions needed a transformer. Our final solution was based on the fact of avoiding a transformer and trying to make the system reliable using 69KV lines (Solution 2). This would ultimately reduce the cost as well.

Carrying out comprehensive analysis with respect to conductors and tower configurations and losses we have zeroed in on the three most optimal solutions.

Cost analysis of the three solutions indicates that solution-1 is the best solution out of the three. The profit obtained due to reduction in losses is more compared to the installation cost. Thus, in addition to making the system more robust and reliable with Zero contingencies, we also gain a profit. Solution-1 proves to be a Win-Win solution.