For a wastewater treatment plant, nothing is more important than preventing a sanitary sewer overflow. An unintended sewage overflow would bear public health, ecological, and economic consequences.
From an operating standpoint, the influent pumping station of a wastewater treatment plant plays a vital role in ensuring the flow of influent sewage throughout the plant’s disinfection processes. Thus, ensuring the reliability of electrical power to the influent pumping station is vital.
Smart Electrical System Design
Washington Suburban Sanitary Commission, a strong proponent for meeting and exceeding environmental standards, selected Helios Electric to design a new electrical system for their influent pumping station at the Parkway Water Resource Recovery Facility.
To meet WSSC’s expectations, their engineers designed a solution to maximize reliability with intelligent switchgear controls using SEL protection and automation devices. Design features included:
Automatic Source Transfer
In the event of a power disturbance of an incoming electrical utility supply, the intelligent switchgear controls automatically transferred to the alternate electrical supply to ensure continued operation of the influent pumping station. This scheme also considered transfer timing with the existing upstream main substation and the downstream motor control centers.
Bumpless Source Restoration
Once a disturbed incoming utility supply was restored and proven, the intelligent switchgear controls automatically retransferred to the normal “redundancy operation” mode using closed-transition, make-before-break, synchronism-check transfers without the need for disrupting the ongoing influent pumping station operations.
Integration with SCADA System
The intelligent switchgear controls were tied into the existing SCADA system to enable real-time monitoring of electrical conditions at the influent pumping station. This included monitoring the health of incoming utility supplies, the status of circuit breakers, and alarm annunciation of faulted components.
With SCADA integration, any anomaly would immediately be known 24/7 at the centralized WSSC headquarters to facilitate the prompt dispatch of qualified personnel to ensure continued operations at the influent pumping station.
Power System Reliability
To establish a reliable electrical distribution system and to safeguard public health, users should always implement intelligent switchgear controls. They make specific recommendations to improve reliability which can save users money.
