WO2022159057A1

WO2022159057A1 - An energy management system to save fuel from the generator according to battery bank's charge status in systems using uninterrupted power supply and generator

Info

Publication number: WO2022159057A1
Application number: PCT/TR2021/051054
Authority: WO
Inventors: Hayri ARABACI; Kemal ERDOGAN; Ismail TASKIRAN
Original assignee: Panoteknik Jenerator Elektrik Sanayi Ve Ticaret Limited Sirketi
Priority date: 2021-10-04
Filing date: 2021-10-18
Publication date: 2022-07-28

Abstract

The invention relates to a system that provides fuel efficiency by controlling the activation and deactivation time of the generator, according to the battery bank charge status information, when there is a power outage in companies using uninterruptible power supply and generators.

Description

AN ENERGY MANAGEMENT SYSTEM TO SAVE FUEL FROM THE GENERATOR ACCORDING TO BATTERY BANK'S CHARGE STATUS IN SYSTEMS USING UNINTERRUPTED POWER SUPPLY AND GENERATOR

TECHNICAL FIELD

BACKGROUND

Generators are put into operation when there is an interruption in the electricity supply from the mains in the companies. Today, this process is carried out automatically, without the need for any operator, thanks to generator management panels. However, it takes at least 8-10 seconds for the generator to be prepared and started from the moment the mains electricity is cut off. Since this short interruption is very important for computers, security equipment or medical devices, institutions such as base stations, banks, hospitals use uninterruptible power supplies to ensure that their important devices continue to work without being affected by this interruption of 8-10 seconds.

While planning the installation of uninterruptible power supplies for this purpose, the power of the relevant devices in the institution and the repair time of the generators as a result of the failure are taken into consideration.

Battery capacity planning is made for the uninterruptible power supply so that these devices can operate for a minimum of 5-10 minutes uninterruptedly (this time may vary according to customer demand and need) in the event of a power outage.

In the event of a power outage in an company outside of working hours, the energy stored in the uninterruptible power supply can feed the loads in the company without the need for a generator for 7-8 times more than planned.

Generator management panels that are currently used activate the generator immediately when the electricity is cut off. It runs the generator continuously until the mains power returns. In this case, the energy stored in the uninterruptible power supply with cheap mains electricity is not used at all. If this stored energy were used, as much fossil fuel could be saved as the corresponding energy.

BRIEF DESCRIPTION OF THE INVENTION

The invention relates to an energy management system that determines the energy level stored in the batteries according to the battery charge information in the uninterruptible power supply when a power outage occurs, and if there is sufficient energy, it supplies the loads with this energy before starting the generator, thus reduces the operating time of the generator.

The invention determines the charge status of the uninterruptible power supply batteries when there is a power outage, and ensures that the loads are fed with these batteries without putting the generator into operation until they fall below the critical level. To determine the battery charge status; battery voltage, load current, ambient temperature and ambient humidity should be monitored. Since the start of the generator is delayed until the battery charge status drops to a critical level when there is an interruption in the mains, the determination of this critical level is designed in an adjustable way according to the battery type and the customer's needs by entering the configuration interface of the invention. When the battery charge level drops to a critical level, the generator is activated. Thus, the operating time of the generator can be shortened.

LIST OF FIGURES

Figure 1. System Diagram

Equivalents of the numbers given in the figure:

1 . Energy Management System

2. Mains

3. Generator

4. Automatic Transfer Switch Board

5. Uninterruptible Power Supply

6. Critical Loads

7. Current Transformers

8. Load DETAILED DESCRIPTION OF THE INVENTION

The energy management system, which is the subject of the invention, comprises parts and modules with the functions mentioned below.

With a connection from the mains (2) to the energy management system (1 ), the mains voltage and frequency can be monitored. In order to monitor these data, the connection is made from the supply phase and neutral ends of the mains (2) to the relevant ports of the energy management system (1 ). The mains voltage coming from the ports is passed over the resistor groups, and the voltage is reduced in accordance with the operating range of the electronic card, and analog signal values are calculated by sampling with the processor on the card. At the same time, the interruption in the mains (2) can be detected from this connection. With a connection from the generator (3) to the energy management system (1 ), the generator (3) voltage and frequency can be monitored. In this connection, the signal reading method is used, which is applied in the mains voltage reading. In addition, thanks to this connection, the start and stop commands can be transmitted to the generator (3).

An automatic transfer switch board (4) is the control system in companies having a generator that transfers energy so that the load can be taken from the mains (2) and fed from the generator (3) when there is a power outage in the mains (2).

Thanks to the automatic transfer switch board (4), the load is connected to only one of the mains (2) or the generator (3) and these two sources are prevented from colliding with each other. With a connection from the energy management system (1 ) to the automatic transfer switch board (4), the signal sent from the determined output of the processor triggers the relevant relay, and the contactors/switches in the automatic transfer switch board (4) change position with the current flowing through this relay. In this way, it is possible to switch between the mains (2) and the generator (3) as the supply source of the load.

With a connection between the uninterruptible power supply (5) and the energy management system (1 ), the voltage of the batteries in the uninterruptible power supply (5), the temperature and humidity of the environment where the batteries are located are monitored. As a voltage monitoring method, the same method used in network voltage monitoring is also used in this section. In order to monitor the temperature and humidity, the data coming to the processor from the sensors that measure the temperature and humidity in the environment where the batteries are located are evaluated.

The current drawn by a critical load (6) is monitored by the connection between a multiple of current transformer (7) and the energy management system (1 ). In order to read the current, a current sensor is placed on the energy management system (1) board. The current coming from the current transformer (7) enters these sensors. The signals coming out of the current sensor are read by the processor in the energy management system (1 ) and the current drawn by the critical load (6) is followed in real-time. The current information obtained here is used in the calculation of the battery state of charge.

Thanks to the connections described above, the energy management system (1 ), constantly monitors the network (2) and the batteries. If there is electricity in the mains (2), the automatic transfer switch board (4) is intervened and the load (8) is fed over the mains (2). In the event of a power outage in the mains (2), the time of the generator (3) to be activated is controlled according to the battery charge status information and the critical level adjustments.

If the battery state of charge is above the critical level, critical loads (6) are fed from the battery, and the generator (3) is not activated. When the battery charge level drops to a critical level the generator (3) is started. And at the same time, the automatic transfer switch board (4) is controlled to ensure that the load is fed through the generator (3). These decisions are taken by the processor as a result of the measurements described above.

When the mains (2) electricity is supplied again at levels accepted as normal, the energy management system (1 ) intervenes the automatic transfer switch board (4) through the processor, separates the load from the generator (3) and provides it to be fed over the mains (2). After the transfer takes place, the generator (3) is also stopped and brought to standby by the energy management system (1 ) via the processor. The voltage and frequency lower/higher levels of the mains (2) electricity, which are considered normal, can be changed according to the need via the user interface of the energy management system (1 ).

The critical level of the battery charge status is determined according to the technical information of the battery used in the company and the user's needs. Adjustments can be made at this level according to the special needs of the company via the interface in the energy management system (1 ). While determining the battery charge status, the battery voltage information obtained from the uninterruptible power supply (5), the critical load current information obtained from the current transformers (7), the temperature and humidity of the environment where the batteries are located are used. Obtaining the battery charge status with only this information does not give precise results. First of all, battery health status is calculated. By using the battery health information, the battery charge status is calculated by the current integration method. Numerical methods, empirical methods, statistical tables or artificial intelligence techniques can be used to determine battery health or battery charge status.

The benefit of the invention can be understood more clearly through two example scenarios. UPS battery capacity installed in an average bank branch where low-power generators are used, can feed critical loads operating at full capacity for approximately 5 minutes during working hours. The same UPS system can supply energy to critical loads for 6-10 times longer due to the lower consumption out of working hours. The average power outage time in OECD countries is around half an hour. In a system in which the energy management system (1) of our invention is not used, in case of a power outage that lasts for half an hour outside working hours, the generator will operate during the interruption and fossil fuel will be consumed, since the generator is activated immediately. However, when the system that is the subject of the invention is used and the critical level is determined as 30%, approximately 2/3 of the energy stored in the UPS batteries will be used primarily and the power outage will be avoided without running the generator at all. Depending on the UPS power and the duration of the power outage, varying amounts of fossil fuel savings and related indirect advantages (such as prevention of environmental pollution) will be achieved. When the power outage is over, the UPS batteries will be recharged with the mains electricity, which is cheaper and more environmentally friendly than the one supplied from the generator. In the second example, where high-power generators are used, the benefit of the invention may be different when there are long-term power outages. An institution (University, factory, shopping mall, dormitory building, etc.) where a generator with a capacity of 1000 KVA consuming an average of 200 liters of fossil fuel per hour is installed, does not consume any energy other than emergency lighting during periods when it is closed such as holidays or pandemics. However, when there is a power outage, the generators are switched on immediately and there is an unnecessarily high consumption of fossil fuels during the outage. By using the energy management system proposed in the invention, it will be possible to prevent this waste in the periods when the institutions are closed.

Claims

CLAIMS An energy management system to save fuel from the generator according to battery bank's charge status in systems using uninterrupted power supply and generator characterized in that comprising;

- An energy management system (1 ); providing the measurement of the voltage of a mains by passing it over a multiple of resistor group and reducing the voltage in accordance with the operating range of an electronic card and calculating analog signal values by sampling with a processor on the card, detecting the interruption in the mains (2), monitoring the generator (3) voltage and frequency via signal reading method, monitoring the voltage of the batteries in the uninterruptible power supply (5), the temperature and humidity of the environment where the batteries are located via the data coming from the sensors that measure the temperature and humidity, to calculate the battery charge status by the current integration method, further comprising a current sensor to read the current, which is drawn by the critical load (6) from the current transformers (7), by the processor,

- An automatic transfer switch board (4) transferring the energy to feed the load from the generator (3) when there is an outage in the mains (2) and providing the load to connect to only one of the mains (2) or the generator (3) and preventing these two sources from colliding with each other. The energy management system (1) of Claim 1 characterized in that comprising a processor deciding to feed the critical loads (6) from the battery if the battery state of charge is above the critical level and with the generator if the battery state of charge is below the critical level and intervening the automatic transfer switch board (4) when the mains (2) electricity is supplied again at levels accepted as normal to separate the load from the generator (3) and provide it to be fed over the mains (2). The energy management system (1) of Claim 2 characterized in that comprising a user interface in which the voltage and frequency lower/higher

7 levels of the mains (2) electricity, which are considered normal, can be changed. The energy management system (1) of Claim 2 characterized in that comprising an interface to determine the critical level of the battery charge status according to the technical information of the battery, the user's needs and company’s needs.

8