Reconfigurable PV Combiner Box for Grounded and Ungrounded Systems

Solution Overview

Problem

Existing solar photovoltaic (PV) combiner systems lack the ability to easily and quickly convert between grounded and ungrounded configurations, which is necessary to comply with different electrical standards and prevent backfeeding that can damage PV arrays.

Innovation Solution

A string combiner box with a multi-pole DC disconnect switch that can be easily configured for either grounded or ungrounded systems by adjusting the connections between the switch poles and output terminals, allowing for seamless conversion between configurations while ensuring compliance with electrical codes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed configuration combiner box is used, then the device structure is simple and reliable, but it cannot adapt to different electrical standards (grounded vs ungrounded systems)

Engineering Contradiction:

Improveadaptability to grounded and ungrounded systemsVSAvoidcombiner box configuration complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The combiner box incorporates a reconfigurable disconnect switch that can dynamically change its internal wiring configuration between grounded and ungrounded systems. The disconnect switch includes movable connections and selectable terminal arrangements that allow the system to adapt its electrical topology based on the specific application requirements, transforming a static device into a dynamically adaptable one.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The combiner box is designed with universal adaptability to serve both grounded and ungrounded PV system configurations. By incorporating a multi-configurable disconnect switch with selectable connection arrangements, a single combiner box design can fulfill multiple electrical system requirements, eliminating the need for separate dedicated devices for different system types.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If separate combiner boxes are used for grounded and ungrounded systems, then each system has optimized dedicated equipment, but inventory requirements and installation complexity increase

Engineering Contradiction:

Improvestandardization of combiner box designVSAvoidcompatibility with different electrical standards

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The combiner box incorporates a reconfigurable disconnect switch that can dynamically change its internal wiring configuration between grounded and ungrounded systems. The disconnect switch includes movable connections and selectable terminal arrangements that allow the system to adapt its electrical topology based on the specific application requirements, transforming a static device into a dynamically adaptable one.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The disconnect switch is designed as a modular component with separable connection elements that can be independently configured. This segmentation allows the same combiner box housing to accommodate different internal wiring arrangements by reconfiguring the modular disconnect switch components, facilitating both standardization and adaptability.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If the disconnect switch configuration is fixed during manufacturing, then installation is straightforward, but field reconfiguration between grounded and ungrounded systems is impossible

Engineering Contradiction:

Improveease of initial installationVSAvoidfield reconfigurability

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The combiner box incorporates a reconfigurable disconnect switch that can dynamically change its internal wiring configuration between grounded and ungrounded systems. The disconnect switch includes movable connections and selectable terminal arrangements that allow the system to adapt its electrical topology based on the specific application requirements, transforming a static device into a dynamically adaptable one.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The combiner box is pre-configured with all necessary connection elements, terminals, and wiring components needed for both grounded and ungrounded systems during manufacturing. This preliminary preparation of reconfigurable elements allows for quick field reconfiguration without requiring additional parts or complex modifications, maintaining ease of operation while enabling adaptability.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS9397235B2Photovoltaic string combiner with disconnect having provision for converting between grounded and ungrounded systems

Publication Date: 2016.07.19 SCHNEIDER ELECTRIC USA INC

AI summary

A string combiner is provided for coupling multiple strings of series-connected photovoltaic (PV) panels in a PV array to downstream equipment, each string including positive and negative conductors. The combiner includes a combiner box containing a busbar connected to the protection devices for receiving and combining the currents from the multiple strings of PV panels, output terminals for connection to the downstream equipment, and a disconnect device within the combiner box and including a multi-pole switch connected to the busbar for disconnecting the downstream equipment from the multiple strings. A plurality of connectors are provided for connecting selected poles of the multi-pole switch to each other or to selected ones of the output terminals in either a grounded or an ungrounded configuration.