# Category Archives: Power System Stability

## Modelling Power System Stability – Part 2, System Variables and Conditions

Welcome and Happy New Year.  I made a small tweak to the model, rearranging the layout of some of the initial settings, and to derive inertia from installed synchronous capacity rather than synchronous supply.  An updated copy of the spreadsheet … Continue reading

Posted in Power System Stability | 13 Comments

## Modelling Power System Stability – Part 1

In a comment Stuart asked “Any chance of a post on synthetic inertia from PV/wind turbines/HVDC links, and why it does or doesn’t help? I keep reading that curtailing the output from the maximum to give some ‘headroom’ allows these … Continue reading

Posted in Power System Stability | 4 Comments

## 7. Analysis of an under frequency event

Let’s take a closer look at the under frequency event that occurred at 9.51am on Thursday June 15th 2017, in the North Island of New Zealand. This is quite a long post with quite a bit of technical detail. The … Continue reading

Posted in Electricity, Power System Stability | 14 Comments

## 6. Control of the prime mover, governors, how it is done and why it matters

The previous article described the relationship between power imbalance and rate of frequency change for the first few seconds after a disturbance in power balance. Important as those few seconds are, the few seconds of energy being provided by the … Continue reading

Posted in Electricity, Power System Stability | 18 Comments

## 5. Frequency stability and energy balance. A description of the interaction between frequency and grid energy flow.

In an earlier post I gave a definition of a stable power system. A stable power system is one that continuously responds and compensates for power/ frequency disturbances, and completes the required adjustments within an acceptable timeframe to adequately compensate … Continue reading

Posted in Electricity, Power System Stability | 2 Comments

## 4. Generator types; synchronous versus asynchronous. What goes on inside the machines?

There are two main types of alternating current machine used for the generation of electricity; synchronous and asynchronous.  The difference between them begins with the way the magnetic field of the rotor interacts with the stator.  Both types of machine … Continue reading

Posted in Electricity, Power System Stability | 2 Comments

## 3. Energy balance, imbalance and a definition of grid stability

The previous article described the grid as having no energy storage, and indeed there is no useful storage in the grid itself.  However, there is energy storage in the form of rotating kinetic energy of certain generators, and the quantity … Continue reading

Posted in Electricity, Power System Stability | 3 Comments

## 2. Electric current is generated ‘on demand’. There is no stored electric current in the grid.

Here’s the second article in the series on electric power system stability: The electric current delivered when you turn on a switch is generated from the instant you operate the switch. There is no store of electric current in the … Continue reading

Posted in Electricity, Power System Stability | 9 Comments

## 1. Electric Power System Stability

I intend to do a few essays about electric power system stability.  I aim to share some concepts about power generation and grids, and in particular how electrical stability is achieved. Some types of generation provide grid stability, other types … Continue reading

Posted in Electricity, Power System Stability | 15 Comments