First note that DC is more efficient at transferring power long distances. AC is typically chosen because it is easier to change the voltage via a transformer.
An equation always needs a variable. If you arbitrarily specify all the values one value will never match the equation.
To back up for future readers Ohm's Law is V=I*R and for power P = V * I
In your scenario you arbitrarily specified all 4;
Power = 100kW
V= 1000V
I= 100A
R =1 ohm
Each time you use these equations you have to take a step back and understand the logical reason you are doing it. To further complicate things in the lower equations it seems that you calculated how much power would be consumed by the power line if it were a large heater. You have to consider the resistance the end users total power generation of the system.
Here is one of many possible use case scenarios for these equations: You have 1kV power source, a 1 ohm power line, and would like to transfer 75 amps of power to your users. How many watts of power will be lost in the power line? How much power to the users receive?
You first calculate your voltage drop in the power line with ohms law.
Voltage_Drop = Current * Line_Resistance
Voltage_Drop = 75amps * 1ohm
Voltage_Drop = 75volts
Power_Loss = 75volts * 75amps = 5625Watts
Voltage_At_Users = 1000volts - 75volts
Voltage_At_Users = 925volts
Power_Used = 925volts * 75amps
Power_Used = 69375Watts
We can confirm our math works by checking that power generated is the same as the power used plus the power lost.
Power_Generated = Power_Used + Power_Lost
Power_Generated = 69375Watts + 5625Watts
Power_Generated = 75000Watts
Power_Generated = 1000volts * 75amps
Power_Generated = 75000Watts
From here you can modify the line voltage and current and see how that changes your delivered power and losses.