PS power supply diagram. Schematic diagram

Introduction

The level of development of energy and electrification, as is known, in the most generalized form reflects the economic and technological potential of any country [2].

Electrification occupies a major place in the formation of absolutely all spheres of the national economy of the Russian Federation, and is considered to be the core of building the economy of our community.

The formation of numerous areas of industry, including oil and gas, is based on today's developments that make extensive use of electrical energy. In this regard, the conditions for the reliability of power supply, the quality of electric energy, and its economical and expedient use have increased.

When designing and operating electrical installations, power plants, substations and systems, it is necessary to make a number of calculations in advance aimed at solving many technical issues and problems, such as:  

(a) Comparison, evaluation and selection of electrical connections of stations and substations;

b) identification of operating conditions of consumers in emergency modes;

c) selection of apparatus and conductors, their inspection according to the working conditions in case of short circuits;

d) design and adjustment of relay protection and automation devices;

e) a number of other tasks.

Object of study: Oil refinery station.

Subject of research: Relay protection system of an oil refinery station.

The purpose of the work: implementation of engine relay protection units of the Mechatronics Scientific and Technical Center (STC).

The novelty of the bachelor's final qualification work is to increase the switching characteristics of the relay protection of automation, by means of commissioning the device, which has advanced functions of relay protection and avoidance, control, signaling of connections, as well as to prevent current overloads in the line.

The relevance of the chosen topic is focused on solving urgent problems. The transition of the Russian energy sector to a market model presents new requirements for all regions. It is important not only to ensure the quality and reliability of electricity supply to consumers, but also to maintain a competitive possible price for electricity.

To date, the main deterrent to the decline in electricity prices is the "underdevelopment" of the industry's network infrastructure:

- congestion of transit and distribution power grids of large districts and industrial hubs;

- Uneconomical redistribution of power flows of electric grids of different classes of rated voltages;

- obsolescence of overload and short-circuit protection equipment.

The topic of the final qualification work is: "Analysis of the relay protection system of an oil refinery with a capacity of 110 MW".

1 Technological part

1.1 Oil Pumping Technology

The main economic factors for the efficient use of pipeline transport are a wide network of pipelines; high rates of construction and rapid commissioning of oil pipelines; comparatively low operating costs during pumping; Possibility of full automation and telemechanization of oil pipelines. These factors make it possible to quickly recoup large capital investments in construction, development of new materials, new equipment and technology, automation and telemetry of pipelines on a large scale. This also explains the increasing share of pipelines in the transportation of oil compared to other modes of transport. Practice shows that the use of pipelines for pumping oil in comparison with rail transportation gives annual savings in operating costs estimated at millions of rubles.  

Oil trunk pipelines include pipelines through which oil is pumped from the main oil refinery station to oil pumping stations and railway, sea and river transshipment oil depots.

At some points along the pipeline route, there may be branches through which part of the pumped oil is delivered to nearby refineries and other consumers.

Oil pipelines with a diameter of 530-1220 mm have become widespread.  

The main technological elements that make up the oil trunk pipeline complex include the linear part, i.e. the pipeline itself with branches, linear valves, crossings through natural and artificial obstacles, and other structures; oil refineries with supply high-voltage power lines; oil depots and loading points intended for transshipment of oil to other modes of transport; communication lines that provide both various types of communication via the oil pipeline and remote control of its facilities.

1.2 Oil refineries

An oil refinery station (OPS) is a complex of facilities and devices for receiving and pumping oil through an oil trunk pipeline (Figure 1).  

Figure 1 – Oil refinery

The main scheme of the oil pumping process of the PS is pumping according to the scheme of operation of the station with "connected tanks". Oil is delivered to the PS through the intake valve No. 1 through the oil supply pipelines and sent to the mud trap filters. Then the oil, purified from mechanical impurities, paraffin-resinous deposits, foreign objects, enters the process tanks (VST) No. 1, 2, as well as the inlet of the booster pumping station. To protect the process pipelines and valves of the tank farm from overpressure, Group 1 safety valves were installed at the PS. Oil discharge from the safety valves is provided for in the process tanks of VSTs No. 1 and 2. To supply oil from the tanks of VSTs No. 1 and 2 to the main pumps, a booster oil pumping station is provided, which is designed to supply oil to the inlet of mainline pumps, since when pumping out of tanks, mainline pumps are not able to pump out oil without first creating oil pressure at their inlet. Oil is pumped out of the tanks by booster pumping unit LEL No. 1,2,3,4 and supplied through gate valve No. 42 to the reception of the main pumping station. Safety valves of the 2nd group are designed to protect against pressure increase of process pipelines and valves between the booster and main pumping stations. On the section of the pipeline from the main pumping station to the oil trunk pipeline, a pressure control unit is installed – dampers No. 1 and 2 to maintain the set pressure values. After the pressure regulator unit is installed, the oil is fed into the oil trunk pipeline through the flow valve of PS No. 59.

The NPS includes:

tank farm;

booster pumping station;

a pumping station with mainline pumping units;

dirt trap filters;

pressure control unit;

units with safety devices;

process pipelines;

systems of water supply, heat supply, ventilation, sewerage, fire extinguishing, water extinguishing, power supply, automation, telemechanics, automated control systems, communications, industrial and household buildings and structures.

To drive mainline pumps at pumping stations, mainly synchronous electric motors of explosion-proof design of the STDP type are used, to drive booster pumps, asynchronous electric motors of the BAOV type are used [1].

Petroleum is an explosive liquid with a flash point of about -20 C0.  

1.3 Linear part of the oil pipeline

The linear part of the oil pipeline is the most expensive and critical part of the oil trunk pipeline. In some cases, capital costs for it reach 80% of the total cost of the pipeline. Accidents on the linear part – ruptures of pipes and leaks from the pipeline – cause the shutdown of the pipeline and cause great damage to the national economy. When designing and operating the linear part of the oil pipeline, the maximum possible pressures arising at each section of the oil pipeline are taken into account. The pressure in each section of the pipeline depends on both the pumping mode and the terrain profile. The greatest pressure is usually at the exit of the PS, as well as at the lowest points of the route, in particular, in mountainous areas after pass points. When constructing a calculated pressure diagram in an oil trunk pipeline, the stations of which operate "from pump to pump", the pressures arising both during the operation of all stations and during the operation of only one head station are taken into account.

Process equipment and devices are installed on the linear part of oil pipelines, which must be automated during remote control of the pipeline. After 15-20 km along the route and at the most critical points of the oil pipeline, such as, for example, river crossings, linear valves with an electric or hydraulic drive are installed.  

With their help, the oil pipeline is divided into separate sections, which can be shut down to prevent large oil losses in case of accidents of the linear part.  

At present, due to the increase in environmental protection requirements, special attention is paid to the problem of monitoring the condition of oil pipelines and their reliability. In order to control the parameters of pumping and the condition of the pipeline, information about the pressure and temperature (for the "hot" oil pipeline) at the most critical points of the route is required. Since the pipeline is protected against corrosion by cathode and drainage stations, information about their parameters is also required. Control of the technological parameters of the route equipment is carried out from the control room via the telemechanics system.