BSC-50E Αρχεία - Infinite Informatics

Earth Fault Monitoring for Power Grids

pratos@indinf.gr — Wed, 02 Dec 2020 23:15:14 +0000

Introduction

This presentation is dedicated for Earth Fault Monitoring for Power Grids .

Autonomous RTUs: BSC-50D, BSC-50E, ADS-260 SIGFOX, ADS-410.

Read the complete application presentation at,

Earth Fault Monitoring EFD v5.pdf

Το άρθρο Earth Fault Monitoring for Power Grids εμφανίστηκε πρώτα στο Infinite Informatics.

Earth fault monitoring in medium voltage substations

it@mms-adv.gr — Wed, 04 Nov 2020 09:00:36 +0000

Introduction

Medium voltage substations require monitoring in order to help power grid operators re-establish power, when network faults occur. Identifying a substation that is out of power is time critical to minimize operations to link back power on the grid.
Modern substations are equipped with earth fault detection relays (EFI or GFI, Earth or Ground Fault Indicator), which provide a digital contact when a line fault occurs. The goal is to reduce drastically the outage time. The normal procedure when a fault is detected is to send maintenance crew to visit a series of substations, identify the stations, which have a fault status and report this back to the control center. Then operations to reroute power are made remotely or on a trial and error basis, which damages the network infrastructure.

Requirements

Identify faults almost online and alert via SMS to a control center.
Minimize needed power rerouting operations.
Identify operational faults from substation equipment.
Manual operations alarming.
Intruder security alarming.

Proposal

BSC-50E and BSC-50D battery powered RTUs are ideal for alerting using SMS. The proposed system consists of:

Special fault detection relays that detect ground fault and provide a plain contact as an alert in the event of a fault.
BSC-50D or BSC-50E devices which are installed to monitor the alarm state on medium voltage substations.

When an earth fault is detected in a substation the result is that the substation is automatically taken off the power grid. Manual or remote operations are needed to place the substation back on the grid. The BSC-50 devices monitor earth faults and transmit respective coded messages via SMS to a control center. Moreover BSC-50 RTUs can be configured to transmit a health message in a scheduled manner to the control center to ensure their operational status.
At the control center a PC running 24/7 software, logs alerts, monitors and reports the operational status of the BSC50 devices. Integration to existing SCADA systems or GIS applications is seamless via an OPC server.

M2M solution

Furthermore, as an extension utilizing M2M functionality, SCOM-100 devices can be used at the control center in order to have an unmanned system. In this case, at the control center, a mimic diagram showing the geographic location of the substations and BSC-50 devices is installed. The mimic diagram has built in colored LED at each substation. The LEDs are cabled to an M2M (machine to machine) alert receiver device as an SCOM-100 unit. The LEDs are connected to digital outputs on the SCOM-100. When an alarm occurs at a BSC-50, two messages are send, one at the control center monitoring station running the monitoring SW and one to the SCOM-100 device switching a LED at the mimic diagram.If the fault is rectified, the LED can be switched off via a manual operation of a switch on the mimic diagram (alarm acknowledgement and rectification). In this way users at the control center can,

Visualize the location of the line faults.
Trace the sequence of failing substations.
Perform remote switching operations (if this is possible in respect to a local substation automation), or to order maintenance crew to visit a specific point on the grid to reroute power and maintain power in the areas which had been taken off the grid.

For example a BSC-50D alerting instantly and sending a health message every week, will operate on one Lithium Thionyl D type battery for more than 12 years.

Why BSC-50

All-in-one cellular GPRS quad band solution
Ultra low power, can run for years on one D type battery
Real-time alerting
Easy to implement and maintain
Seamless connection to SCADA via OPC server
SMS alerts and M2M functionality

M2M Reservoir Level Control

it@mms-adv.gr — Wed, 07 Oct 2020 08:24:13 +0000

Introduction

The water level regulation of a reservoir, used for irrigation purposes, is the requirement for an M2M control system. The reservoir is located in an off-grid area, on a hill. A pump house located below the hill, feeds the reservoir from a near river. The system is shown in the figure below.

Proposal

A BSC-50E battery powered RTU with an ultrasonic sensor, is used for tracking the reservoir water level. BSC-50E sends M2M commands to an ARC-10 GSM controller, which controls the pump operation through its relay outputs. The pump automation system (e.g. a PLC) supports the following functions:

Function	Actuator / Indicator	Action
Start Operation	Push button (Start button)	Enable Remote control, Turn Pump ON for t=T1 ¹⁾
Stop Operation	Push button (Stop button) or Digital input IN1	High pulse on IN1–> Cancel system operation
Remote Control	Digital input IN2	High to Low transition –> Turn Pump ON for t=T2 ²⁾, Low to High transition –> Stop PUMP)
Thermal protection	Digital output OUT1	Low –> Normal operation, High –> Protection active (Operation cancelled)

¹⁾ T1 is the time, depending on the pump flow rate, needed to fill the reservoir from empty state to a level between H and HH.
²⁾ T2 is the time it takes to reach a level between H and HH, starting with water level L.

ARC-10 outputs DO1, DO2 are connected to IN1 and IN2 of the pump control system respectively. The thermal protection indication (OUT1) is connected to ARC-10, digital input 1 (DI1).
On the other side, an ultrasonic sensor (Massa M300) is connected to BSC-50E, analog input 1 (AI1). Two alarm limits are set on the analog measurement:

Alarm limit low, which corresponds to level L.
Alarm limit high, which corresponds to level H.

The water level is logged every hour. A level switch, indicating the HH water level, is connected to BSC-50E, digital input 1 (DI1).

Operation description

After start up, the pump feeds the reservoir, until the water level reaches the high limit (Level H). In the meantime BSC-50E scans the water level every minute.
On reaching the high limit, BSC-50E sends an M2M SMS, commanding the ARC-10 unit to switch DO2 on. The pump is turned off. At the same time, BSC-50E switches level scanning to a lower rate (e.g. every 15 minutes), to save power.
The pump remains in the hold state until the water level drops, due to irrigation flow, below the low limit. Then BSC-50E sends an SMS, commanding the ARC-10 unit to switch DO2 off. The pump is turned on. At the same time, it switches to higher sampling rate (every minute) to keep track of the reservoir filling.
Once a day, BSC-50E sends the water level logs to a system administrator.

Alerting

If the water level reaches, for any reason, the HH limit, the level switch activates an alarm on BSC-50E, DI1. BSC-50E sends an SMS command to the ARC-10 unit, to switch DO1 on for 2 seconds. The feeding system operation is cancelled. An additional SMS is sent to maintenance personnel, alerting for the malfunction.
In case of pump overheating, ARC-10 sends a respective alert to maintenance personnel.

Battery lifetime

The lifetime of the BSC-50E internal battery (LSH-20) depends on the water feeding cycles per day, as shown in the table below:

Feeding cycles	M2M SMS	Daily consumption [mAh]	Battery Lifetime [Years]
2	4	16.7	2.13
4	8	20.2	1.76
6	12	24.6	1.44
8	16	31.0	1.14
10	20	37.4	0.95