The action was brought by the Commerce Commission, whose deputy chairwoman Sue Begg said Vector failed to deliver the service Auckland consumers had a right to expect.
She said the commission was concerned at Vector's overall decision-making and management practices.
Chief networks officer Andre Botha said Auckland's growth, and the impact it was having on the company's operating environment, was a constant challenge.
"We are constantly evolving our business to meet Auckland's significant growth through ongoing investment decisions that improve long-term outcomes for customers and improve the performance of Vector's network.''
Justice Alisa Duffy singled out several Vector failings, including its vegetation management to prevent trees falling on lines.
Botha said Vector had significantly increased investment in our vegetation management programme, including an education programme for tree owners.
The government had committed to this year review tree regulations.
Depending on voltage of lines, growth around them must be 0.5m to 4m away.
''Under current regulations we are limited in our ability to trim vegetation around our powerlines, which can have a negative impact on our network,'' Botha said.
The judge also criticised the company for not planning for the foreseeable increase in traffic and allocating work crews to ensure a fast response.
Botha said Vector was working with Auckland Council, Vector's outage response crews now have access to bus lanes to reach faults faster.
That was helping to reduce excessive restoration delays caused by Auckland traffic.
He said restoration times could also be affected by the time lines staff had to wait for emergency services to allow access to a fault site.
Aspects of life cycle asset management were also found to have fallen short of good industry practice.
Botha said Vector was about to release a 10-year plan for its assets.
''In it we lay out how we intend to leverage new and existing network technology to deliver on our commitment to Auckland,'' he said.
