Help - Gas Network Operator Handbook?
Help - Gas Network Operator Handbook?
(OP)
Hi,
I am looking for a good handbook which details the responsibilities of a gas network operator ideally in different gas grid states.. For example, what are the degrees of freedom the operator has? If the pressure is too high in one part of the grid he may open another branch, use a storage area, control the compressor stations, or? I am quite new in this field so at this point any literature would be really great to have, because I have been looking for quite some time online and still haven't found anything on this topic. Many thanks in advance.
I am looking for a good handbook which details the responsibilities of a gas network operator ideally in different gas grid states.. For example, what are the degrees of freedom the operator has? If the pressure is too high in one part of the grid he may open another branch, use a storage area, control the compressor stations, or? I am quite new in this field so at this point any literature would be really great to have, because I have been looking for quite some time online and still haven't found anything on this topic. Many thanks in advance.





RE: Help - Gas Network Operator Handbook?
RE: Help - Gas Network Operator Handbook?
What else you need?
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RE: Help - Gas Network Operator Handbook?
High downstream pressure should only occur if regulators fail open. OPSO valves (or relief valves) can be included at the design stage.
There are many issues to be considered in a network, including network modelling, need for dual-feed by two or more reg stations, increased risk of deliberate damage by public, unaccounted-for-gas, etc. There is a regular and frequent need to hot tap e.g. new service mains to new customers, etc.
For distribution pressures, there are more material options i.e. you don't have to use steel, with PE being very popular. Locating a PE pipe is not so easy, so there are issues to think about. Use of PE pipe allows squeeze-off, but risks need to be managed.
RE: Help - Gas Network Operator Handbook?
RE: Help - Gas Network Operator Handbook?
I hate Windowz 8!!!!
RE: Help - Gas Network Operator Handbook?
RE: Help - Gas Network Operator Handbook?
1. What can you do to control/vary the pressure level and mass flow? Which tools can you use, without influencing the customers?
2. What happens to the pressure level/mass flow when you connect an additional pipeline at the connection point? How is the storage volume of the network affected?
3. What happens to the pressure, storage volume, and mass flow when you are switching off a pipeline?
4. What happens with the mass flow/pressure if you have an additional feed-in/feed-out?
5. What happens if you use valves to reduce/increase a mass flow in one pipeline of the network?
6. How can you describe these relations mathematically?
7. What is the relation between pressure level and stored volume in the network?
I hope somebody can help. Thank you in advance.
RE: Help - Gas Network Operator Handbook?
A planning dept would do this modelling work, designing the reticulation, with some spare capacity. They'll advise the engineering dept where they need regulator stations and what inlet pressure is available, what outlet pressure is required and max/min flows are expected.
Mostly, when an additional customer is connected, this isn't a problem as domestic consumers doesn't consume much gas. For new industrial customer, a suitable feed main is selected. This is not always the closest main to the site, due to capacity, pressure, etc of the closest main.
Over time, a trunk main may approach its capacity, and a decision is required whether to add a duplicate main, or replace the existing main with a larger diameter.
So, my answers to your questions:
1. Network modelling determines the network pressures. Pressures are achieved by regulator stations distributed within the network.
2. If the main has spare capacity, then the pressure doesn't fall. Note, that even without new customers, customer demand isn't constant all year round. Typically, much higher usage in winter vs summer, for example. So, the network must be designed to handle this.
3. Switching a pipeline off is something that I've come across. Do you mean decommission? What are the reasons you would want to switch off a main?
4. See 2.
5. Network control by throttling valves is something you would want to avoid. You could accidentally starve a main of gas, air would get in, and it is a big job to revive the main.
6. Computational fluid dynamics
7. The larger the volume:
- the less pressure variation you'll have when a small amount of gas is consumed
- regulator stations will not have to work as hard
RE: Help - Gas Network Operator Handbook?
Switching a pipeline of is something that I haven't come across.
RE: Help - Gas Network Operator Handbook?
For example, the network operator will make a decision when to store gas in a storage site or when as line pack correct? How does he make these decisions on a technical level? For instance, when filling a gas storage site, how does he know how much to store and at what pressures/mass flows etc? Is this all automated for him so he doesn't have to really think about it?
Sorry if my questions seem very fundamental, but this is all very new to me. I appreciate the responses you've all given. I'm still trying to get a firm grasp on these concepts.
RE: Help - Gas Network Operator Handbook?
The UK gas network is a transportation system and many similar systems in Europe are gradually going the same way supposedly to enhance competition between suppliers or "shippers". Hence the commercial decision about when to store gas or take it from LNG facilities or source from one particular input point rather than another is a commercial one undertaken by the shippers. The transporter has a duty then to make it all work and has entire departments constantly looking at how to this in the most efficient manner by means of a constant running network model updated with real numbers. The transporter makes money by transporting gas in the most efficient manner possible and the shipper by selling it at the best price he can and sourcing it a the lowest price he can.
Over time the gas system operators gain an understanding of "typical" flows and the impact of different predicted temperatures on gas supplies and plan accordingly. All the shippers are required to balance their outflow to customers with inlet volumes to match. If they don't then the system might fail, but in reality the transporter has powers to buy gas needed to balance the network and then back charge the shippers along with a fine for not balancing his flows. The operation of this is a regulated function governed by a set of rules about 100 pages long called the "Uniform Network Code". See this http://www.gasgovernance.co.uk/unc for further details.
I think you really need to try and talk to the planning department of a large scale operator if you want to discover more, but I wish you luck in this as often this is seen as confidential information.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Help - Gas Network Operator Handbook?
RE: Help - Gas Network Operator Handbook?
Many transmission systems are effective monopolies, often nationalised or government institutions (or were) and the first thought of most of them is to say nothing or restrict access to information on the basis of national security or commercial confidentiality.
Your best bet IMO is to try and talk to a sympathetic gas network planner in an transmission company and get your information from them.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way